/*
  * Copyright (c) 2014 Lukasz Marek
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 //TODO: support for more formats
 //TODO: support for more systems.
 //TODO: implement X11, Windows, Mac OS native default window. SDL 1.2 doesn't allow to render to custom thread.
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <stddef.h>
 
 #include "config.h"
 
 #if HAVE_OPENGL_GL3_H
 #include <OpenGL/gl3.h>
 #elif HAVE_ES2_GL_H
 #include <ES2/gl.h>
 #else
 #include <GL/gl.h>
 #include <GL/glext.h>
 #endif
 #if HAVE_GLXGETPROCADDRESS
 #include <GL/glx.h>
 #endif
 #if HAVE_WINDOWS_H
 #include <windows.h>
 #endif
 
 #if HAVE_SDL
 #include <SDL.h>
 #endif
 
 #include "libavutil/common.h"
 #include "libavutil/pixdesc.h"
 #include "libavutil/log.h"
 #include "libavutil/opt.h"
 #include "libavutil/avassert.h"
 #include "libavutil/avstring.h"
 #include "libavformat/avformat.h"

 #include "libavformat/internal.h"

 #include "libavdevice/avdevice.h"
 #include "opengl_enc_shaders.h"
 
 #ifndef APIENTRY
 #define APIENTRY
 #endif
 

 /* FF_GL_RED_COMPONENT is used for plannar pixel types.

  * Only red component is sampled in shaders.
  * On some platforms GL_RED is not availabe and GL_LUMINANCE have to be used,
  * but since OpenGL 3.0 GL_LUMINANCE is deprecated.
  * GL_RED produces RGBA = value, 0, 0, 1.
  * GL_LUMINANCE produces RGBA = value, value, value, 1.
  * Note: GL_INTENSITY may also be used which produce RGBA = value, value, value, value. */
 #if defined(GL_RED)

 #define FF_GL_RED_COMPONENT GL_RED

 #elif defined(GL_LUMINANCE)

 #define FF_GL_RED_COMPONENT GL_LUMINANCE

 #else

 #define FF_GL_RED_COMPONENT 0x1903; //GL_RED

 #endif
 
 /* Constants not defined for iOS */
 #define FF_GL_UNSIGNED_BYTE_3_3_2 0x8032
 #define FF_GL_UNSIGNED_BYTE_2_3_3_REV 0x8362
 #define FF_GL_UNSIGNED_SHORT_1_5_5_5_REV 0x8366

 #define FF_GL_UNPACK_ROW_LENGTH          0x0CF2

 
 /* MinGW exposes only OpenGL 1.1 API */
 #define FF_GL_ARRAY_BUFFER                0x8892
 #define FF_GL_ELEMENT_ARRAY_BUFFER        0x8893
 #define FF_GL_STATIC_DRAW                 0x88E4
 #define FF_GL_FRAGMENT_SHADER             0x8B30
 #define FF_GL_VERTEX_SHADER               0x8B31
 #define FF_GL_COMPILE_STATUS              0x8B81
 #define FF_GL_LINK_STATUS                 0x8B82
 #define FF_GL_INFO_LOG_LENGTH             0x8B84
 typedef void   (APIENTRY *FF_PFNGLACTIVETEXTUREPROC) (GLenum texture);
 typedef void   (APIENTRY *FF_PFNGLGENBUFFERSPROC) (GLsizei n, GLuint *buffers);
 typedef void   (APIENTRY *FF_PFNGLDELETEBUFFERSPROC) (GLsizei n, const GLuint *buffers);
 typedef void   (APIENTRY *FF_PFNGLBUFFERDATAPROC) (GLenum target, ptrdiff_t size, const GLvoid *data, GLenum usage);
 typedef void   (APIENTRY *FF_PFNGLBINDBUFFERPROC) (GLenum target, GLuint buffer);
 typedef GLint  (APIENTRY *FF_PFNGLGETATTRIBLOCATIONPROC) (GLuint program, const char *name);
 typedef void   (APIENTRY *FF_PFNGLENABLEVERTEXATTRIBARRAYPROC) (GLuint index);
 typedef void   (APIENTRY *FF_PFNGLVERTEXATTRIBPOINTERPROC) (GLuint index, GLint size, GLenum type, GLboolean normalized, GLsizei stride, uintptr_t pointer);
 typedef GLint  (APIENTRY *FF_PFNGLGETUNIFORMLOCATIONPROC) (GLuint program, const char *name);
 typedef void   (APIENTRY *FF_PFNGLUNIFORM1FPROC) (GLint location, GLfloat v0);
 typedef void   (APIENTRY *FF_PFNGLUNIFORM1IPROC) (GLint location, GLint v0);
 typedef void   (APIENTRY *FF_PFNGLUNIFORMMATRIX4FVPROC) (GLint location, GLsizei count, GLboolean transpose, const GLfloat *value);
 typedef GLuint (APIENTRY *FF_PFNGLCREATEPROGRAMPROC) (void);
 typedef void   (APIENTRY *FF_PFNGLDELETEPROGRAMPROC) (GLuint program);
 typedef void   (APIENTRY *FF_PFNGLUSEPROGRAMPROC) (GLuint program);
 typedef void   (APIENTRY *FF_PFNGLLINKPROGRAMPROC) (GLuint program);
 typedef void   (APIENTRY *FF_PFNGLGETPROGRAMIVPROC) (GLuint program, GLenum pname, GLint *params);
 typedef void   (APIENTRY *FF_PFNGLGETPROGRAMINFOLOGPROC) (GLuint program, GLsizei bufSize, GLsizei *length, char *infoLog);
 typedef void   (APIENTRY *FF_PFNGLATTACHSHADERPROC) (GLuint program, GLuint shader);
 typedef GLuint (APIENTRY *FF_PFNGLCREATESHADERPROC) (GLenum type);
 typedef void   (APIENTRY *FF_PFNGLDELETESHADERPROC) (GLuint shader);
 typedef void   (APIENTRY *FF_PFNGLCOMPILESHADERPROC) (GLuint shader);
 typedef void   (APIENTRY *FF_PFNGLSHADERSOURCEPROC) (GLuint shader, GLsizei count, const char* *string, const GLint *length);
 typedef void   (APIENTRY *FF_PFNGLGETSHADERIVPROC) (GLuint shader, GLenum pname, GLint *params);
 typedef void   (APIENTRY *FF_PFNGLGETSHADERINFOLOGPROC) (GLuint shader, GLsizei bufSize, GLsizei *length, char *infoLog);
 
 typedef struct FFOpenGLFunctions {
     FF_PFNGLACTIVETEXTUREPROC glActiveTexture;                     //Require GL ARB multitexture
     FF_PFNGLGENBUFFERSPROC glGenBuffers;                           //Require GL_ARB_vertex_buffer_object
     FF_PFNGLDELETEBUFFERSPROC glDeleteBuffers;                     //Require GL_ARB_vertex_buffer_object
     FF_PFNGLBUFFERDATAPROC glBufferData;                           //Require GL_ARB_vertex_buffer_object
     FF_PFNGLBINDBUFFERPROC glBindBuffer;                           //Require GL_ARB_vertex_buffer_object
     FF_PFNGLGETATTRIBLOCATIONPROC glGetAttribLocation;             //Require GL_ARB_vertex_shader
     FF_PFNGLENABLEVERTEXATTRIBARRAYPROC glEnableVertexAttribArray; //Require GL_ARB_vertex_shader
     FF_PFNGLVERTEXATTRIBPOINTERPROC glVertexAttribPointer;         //Require GL_ARB_vertex_shader
     FF_PFNGLGETUNIFORMLOCATIONPROC glGetUniformLocation;           //Require GL_ARB_shader_objects
     FF_PFNGLUNIFORM1FPROC glUniform1f;                             //Require GL_ARB_shader_objects
     FF_PFNGLUNIFORM1IPROC glUniform1i;                             //Require GL_ARB_shader_objects
     FF_PFNGLUNIFORMMATRIX4FVPROC glUniformMatrix4fv;               //Require GL_ARB_shader_objects
     FF_PFNGLCREATEPROGRAMPROC glCreateProgram;                     //Require GL_ARB_shader_objects
     FF_PFNGLDELETEPROGRAMPROC glDeleteProgram;                     //Require GL_ARB_shader_objects
     FF_PFNGLUSEPROGRAMPROC glUseProgram;                           //Require GL_ARB_shader_objects
     FF_PFNGLLINKPROGRAMPROC glLinkProgram;                         //Require GL_ARB_shader_objects
     FF_PFNGLGETPROGRAMIVPROC glGetProgramiv;                       //Require GL_ARB_shader_objects
     FF_PFNGLGETPROGRAMINFOLOGPROC glGetProgramInfoLog;             //Require GL_ARB_shader_objects
     FF_PFNGLATTACHSHADERPROC glAttachShader;                       //Require GL_ARB_shader_objects
     FF_PFNGLCREATESHADERPROC glCreateShader;                       //Require GL_ARB_shader_objects
     FF_PFNGLDELETESHADERPROC glDeleteShader;                       //Require GL_ARB_shader_objects
     FF_PFNGLCOMPILESHADERPROC glCompileShader;                     //Require GL_ARB_shader_objects
     FF_PFNGLSHADERSOURCEPROC glShaderSource;                       //Require GL_ARB_shader_objects
     FF_PFNGLGETSHADERIVPROC glGetShaderiv;                         //Require GL_ARB_shader_objects
     FF_PFNGLGETSHADERINFOLOGPROC glGetShaderInfoLog;               //Require GL_ARB_shader_objects
 } FFOpenGLFunctions;
 
 #define OPENGL_ERROR_CHECK(ctx) \
 {\
     GLenum err_code; \
     if ((err_code = glGetError()) != GL_NO_ERROR) { \
         av_log(ctx, AV_LOG_ERROR, "OpenGL error occurred in '%s', line %d: %d\n", __FUNCTION__, __LINE__, err_code); \
         goto fail; \
     } \
 }\
 
 typedef struct OpenGLVertexInfo
 {
     float x, y, z;    ///<Position
     float s0, t0;     ///<Texture coords
 } OpenGLVertexInfo;
 
 /* defines 2 triangles to display */
 static GLushort g_index[6] =
 {
     0, 1, 2,
     0, 3, 2,
 };
 
 typedef struct OpenGLContext {
     AVClass *class;                    ///< class for private options
 
 #if HAVE_SDL
     SDL_Surface *surface;
 #endif
     FFOpenGLFunctions glprocs;
 
     uint8_t background[4];             ///< Background color
     int no_window;                     ///< 0 for create default window
     char *window_title;                ///< Title of the window
 
     /* OpenGL implementation limits */
     GLint max_texture_size;            ///< Maximum texture size
     GLint max_viewport_width;          ///< Maximum viewport size
     GLint max_viewport_height;         ///< Maximum viewport size
     int non_pow_2_textures;            ///< 1 when non power of 2 textures are supported

     int unpack_subimage;               ///< 1 when GL_EXT_unpack_subimage is available

 
     /* Current OpenGL configuration */
     GLuint program;                    ///< Shader program

     GLuint vertex_shader;              ///< Vertex shader
     GLuint fragment_shader;            ///< Fragment shader for current pix_pmt

     GLuint texture_name[4];            ///< Textures' IDs
     GLuint index_buffer;               ///< Index buffer
     GLuint vertex_buffer;              ///< Vertex buffer
     OpenGLVertexInfo vertex[4];        ///< VBO
     GLint projection_matrix_location;  ///< Uniforms' locations
     GLint model_view_matrix_location;
     GLint color_map_location;
     GLint chroma_div_w_location;
     GLint chroma_div_h_location;
     GLint texture_location[4];
     GLint position_attrib;             ///< Attibutes' locations
     GLint texture_coords_attrib;
 
     GLfloat projection_matrix[16];     ///< Projection matrix
     GLfloat model_view_matrix[16];     ///< Modev view matrix
     GLfloat color_map[16];             ///< RGBA color map matrix
     GLfloat chroma_div_w;              ///< Chroma subsampling w ratio
     GLfloat chroma_div_h;              ///< Chroma subsampling h ratio
 
     /* Stream information */
     GLenum format;
     GLenum type;
     int width;                         ///< Stream width
     int height;                        ///< Stream height
     enum AVPixelFormat pix_fmt;        ///< Stream pixel format
     int picture_width;                 ///< Rendered width
     int picture_height;                ///< Rendered height
     int window_width;
     int window_height;
 } OpenGLContext;
 

 static const struct OpenGLFormatDesc {
     enum AVPixelFormat fixel_format;
     const char * const * fragment_shader;
     GLenum format;
     GLenum type;
 } opengl_format_desc[] = {

     { AV_PIX_FMT_YUV420P,    &FF_OPENGL_FRAGMENT_SHADER_YUV_PLANAR,  FF_GL_RED_COMPONENT, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_YUV444P,    &FF_OPENGL_FRAGMENT_SHADER_YUV_PLANAR,  FF_GL_RED_COMPONENT, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_YUV422P,    &FF_OPENGL_FRAGMENT_SHADER_YUV_PLANAR,  FF_GL_RED_COMPONENT, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_YUV410P,    &FF_OPENGL_FRAGMENT_SHADER_YUV_PLANAR,  FF_GL_RED_COMPONENT, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_YUV411P,    &FF_OPENGL_FRAGMENT_SHADER_YUV_PLANAR,  FF_GL_RED_COMPONENT, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_YUV440P,    &FF_OPENGL_FRAGMENT_SHADER_YUV_PLANAR,  FF_GL_RED_COMPONENT, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_YUV420P16,  &FF_OPENGL_FRAGMENT_SHADER_YUV_PLANAR,  FF_GL_RED_COMPONENT, GL_UNSIGNED_SHORT },
     { AV_PIX_FMT_YUV422P16,  &FF_OPENGL_FRAGMENT_SHADER_YUV_PLANAR,  FF_GL_RED_COMPONENT, GL_UNSIGNED_SHORT },
     { AV_PIX_FMT_YUV444P16,  &FF_OPENGL_FRAGMENT_SHADER_YUV_PLANAR,  FF_GL_RED_COMPONENT, GL_UNSIGNED_SHORT },
     { AV_PIX_FMT_YUVA420P,   &FF_OPENGL_FRAGMENT_SHADER_YUVA_PLANAR, FF_GL_RED_COMPONENT, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_YUVA444P,   &FF_OPENGL_FRAGMENT_SHADER_YUVA_PLANAR, FF_GL_RED_COMPONENT, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_YUVA422P,   &FF_OPENGL_FRAGMENT_SHADER_YUVA_PLANAR, FF_GL_RED_COMPONENT, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_YUVA420P16, &FF_OPENGL_FRAGMENT_SHADER_YUVA_PLANAR, FF_GL_RED_COMPONENT, GL_UNSIGNED_SHORT },
     { AV_PIX_FMT_YUVA422P16, &FF_OPENGL_FRAGMENT_SHADER_YUVA_PLANAR, FF_GL_RED_COMPONENT, GL_UNSIGNED_SHORT },
     { AV_PIX_FMT_YUVA444P16, &FF_OPENGL_FRAGMENT_SHADER_YUVA_PLANAR, FF_GL_RED_COMPONENT, GL_UNSIGNED_SHORT },

     { AV_PIX_FMT_RGB24,      &FF_OPENGL_FRAGMENT_SHADER_RGB_PACKET,  GL_RGB, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_BGR24,      &FF_OPENGL_FRAGMENT_SHADER_RGB_PACKET,  GL_RGB, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_0RGB,       &FF_OPENGL_FRAGMENT_SHADER_RGB_PACKET,  GL_RGBA, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_RGB0,       &FF_OPENGL_FRAGMENT_SHADER_RGB_PACKET,  GL_RGBA, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_0BGR,       &FF_OPENGL_FRAGMENT_SHADER_RGB_PACKET,  GL_RGBA, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_BGR0,       &FF_OPENGL_FRAGMENT_SHADER_RGB_PACKET,  GL_RGBA, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_RGB565,     &FF_OPENGL_FRAGMENT_SHADER_RGB_PACKET,  GL_RGB, GL_UNSIGNED_SHORT_5_6_5 },
     { AV_PIX_FMT_BGR565,     &FF_OPENGL_FRAGMENT_SHADER_RGB_PACKET,  GL_RGB, GL_UNSIGNED_SHORT_5_6_5 },
     { AV_PIX_FMT_RGB555,     &FF_OPENGL_FRAGMENT_SHADER_RGB_PACKET,  GL_RGBA, FF_GL_UNSIGNED_SHORT_1_5_5_5_REV },
     { AV_PIX_FMT_BGR555,     &FF_OPENGL_FRAGMENT_SHADER_RGB_PACKET,  GL_RGBA, FF_GL_UNSIGNED_SHORT_1_5_5_5_REV },
     { AV_PIX_FMT_RGB8,       &FF_OPENGL_FRAGMENT_SHADER_RGB_PACKET,  GL_RGB, FF_GL_UNSIGNED_BYTE_3_3_2 },
     { AV_PIX_FMT_BGR8,       &FF_OPENGL_FRAGMENT_SHADER_RGB_PACKET,  GL_RGB, FF_GL_UNSIGNED_BYTE_2_3_3_REV },
     { AV_PIX_FMT_RGB48,      &FF_OPENGL_FRAGMENT_SHADER_RGB_PACKET,  GL_RGB, GL_UNSIGNED_SHORT },
     { AV_PIX_FMT_ARGB,       &FF_OPENGL_FRAGMENT_SHADER_RGBA_PACKET, GL_RGBA, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_RGBA,       &FF_OPENGL_FRAGMENT_SHADER_RGBA_PACKET, GL_RGBA, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_ABGR,       &FF_OPENGL_FRAGMENT_SHADER_RGBA_PACKET, GL_RGBA, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_BGRA,       &FF_OPENGL_FRAGMENT_SHADER_RGBA_PACKET, GL_RGBA, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_RGBA64,     &FF_OPENGL_FRAGMENT_SHADER_RGBA_PACKET, GL_RGBA, GL_UNSIGNED_SHORT },
     { AV_PIX_FMT_BGRA64,     &FF_OPENGL_FRAGMENT_SHADER_RGBA_PACKET, GL_RGBA, GL_UNSIGNED_SHORT },

     { AV_PIX_FMT_GBRP,       &FF_OPENGL_FRAGMENT_SHADER_RGB_PLANAR,  FF_GL_RED_COMPONENT, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_GBRP16,     &FF_OPENGL_FRAGMENT_SHADER_RGB_PLANAR,  FF_GL_RED_COMPONENT, GL_UNSIGNED_SHORT },
     { AV_PIX_FMT_GBRAP,      &FF_OPENGL_FRAGMENT_SHADER_RGBA_PLANAR, FF_GL_RED_COMPONENT, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_GBRAP16,    &FF_OPENGL_FRAGMENT_SHADER_RGBA_PLANAR, FF_GL_RED_COMPONENT, GL_UNSIGNED_SHORT },

     { AV_PIX_FMT_GRAY8,      &FF_OPENGL_FRAGMENT_SHADER_GRAY,        FF_GL_RED_COMPONENT, GL_UNSIGNED_BYTE },
     { AV_PIX_FMT_GRAY16,     &FF_OPENGL_FRAGMENT_SHADER_GRAY,        FF_GL_RED_COMPONENT, GL_UNSIGNED_SHORT },

     { AV_PIX_FMT_NONE,       NULL }
 };
 

 static av_cold int opengl_prepare_vertex(AVFormatContext *s);

 static int opengl_draw(AVFormatContext *h, void *intput, int repaint, int is_pkt);

 static av_cold int opengl_init_context(OpenGLContext *opengl);
 

 static av_cold void opengl_deinit_context(OpenGLContext *opengl)
 {
     glDeleteTextures(4, opengl->texture_name);
     opengl->texture_name[0] = opengl->texture_name[1] =
     opengl->texture_name[2] = opengl->texture_name[3] = 0;
     if (opengl->glprocs.glUseProgram)
         opengl->glprocs.glUseProgram(0);
     if (opengl->glprocs.glDeleteProgram) {
         opengl->glprocs.glDeleteProgram(opengl->program);
         opengl->program = 0;
     }
     if (opengl->glprocs.glDeleteShader) {
         opengl->glprocs.glDeleteShader(opengl->vertex_shader);
         opengl->glprocs.glDeleteShader(opengl->fragment_shader);
         opengl->vertex_shader = opengl->fragment_shader = 0;
     }
     if (opengl->glprocs.glBindBuffer) {
         opengl->glprocs.glBindBuffer(FF_GL_ARRAY_BUFFER, 0);
         opengl->glprocs.glBindBuffer(FF_GL_ELEMENT_ARRAY_BUFFER, 0);
     }
     if (opengl->glprocs.glDeleteBuffers) {
         opengl->glprocs.glDeleteBuffers(2, &opengl->index_buffer);
         opengl->vertex_buffer = opengl->index_buffer = 0;
     }
 }
 

 static int opengl_resize(AVFormatContext *h, int width, int height)
 {
     int ret = 0;
     OpenGLContext *opengl = h->priv_data;
     opengl->window_width = width;
     opengl->window_height = height;
     /* max_viewport_width == 0 means write_header was not called yet. */
     if (opengl->max_viewport_width) {
         if (opengl->no_window &&
             (ret = avdevice_dev_to_app_control_message(h, AV_DEV_TO_APP_PREPARE_WINDOW_BUFFER, NULL , 0)) < 0) {
             av_log(opengl, AV_LOG_ERROR, "Application failed to prepare window buffer.\n");
             goto end;
         }
         if ((ret = opengl_prepare_vertex(h)) < 0)
             goto end;

         ret = opengl_draw(h, NULL, 1, 0);

     }
   end:
     return ret;
 }
 
 static int opengl_control_message(AVFormatContext *h, int type, void *data, size_t data_size)
 {
     OpenGLContext *opengl = h->priv_data;
     switch(type) {
     case AV_APP_TO_DEV_WINDOW_SIZE:
         if (data) {
             AVDeviceRect *message = data;
             return opengl_resize(h, message->width, message->height);
         }
         return AVERROR(EINVAL);
     case AV_APP_TO_DEV_WINDOW_REPAINT:
         return opengl_resize(h, opengl->window_width, opengl->window_height);
     }
     return AVERROR(ENOSYS);
 }
 
 #if HAVE_SDL
 static int opengl_sdl_recreate_window(OpenGLContext *opengl, int width, int height)
 {
     opengl->surface = SDL_SetVideoMode(width, height,
                                        32, SDL_OPENGL | SDL_RESIZABLE);
     if (!opengl->surface) {
         av_log(opengl, AV_LOG_ERROR, "Unable to set video mode: %s\n", SDL_GetError());
         return AVERROR_EXTERNAL;
     }
     SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 8);
     SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 8);
     SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 8);
     SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8);
     SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
     return 0;
 }
 
 static int opengl_sdl_process_events(AVFormatContext *h)
 {
     int ret;
     OpenGLContext *opengl = h->priv_data;
     SDL_Event event;
     SDL_PumpEvents();
     while (SDL_PeepEvents(&event, 1, SDL_GETEVENT, SDL_ALLEVENTS) > 0) {
         switch (event.type) {
         case SDL_QUIT:
             return AVERROR(EIO);
         case SDL_KEYDOWN:
             switch (event.key.keysym.sym) {
             case SDLK_ESCAPE:
             case SDLK_q:
                 return AVERROR(EIO);
             }
             return 0;
         case SDL_VIDEORESIZE: {
             char buffer[100];
             int reinit;
             AVDeviceRect message;
             /* clean up old context because SDL_SetVideoMode may lose its state. */
             SDL_VideoDriverName(buffer, sizeof(buffer));
             reinit = !av_strncasecmp(buffer, "quartz", sizeof(buffer));
             if (reinit) {

                 opengl_deinit_context(opengl);

             }
             if ((ret = opengl_sdl_recreate_window(opengl, event.resize.w, event.resize.h)) < 0)
                 return ret;
             if (reinit && (ret = opengl_init_context(opengl)) < 0)
                 return ret;
             message.width = opengl->surface->w;
             message.height = opengl->surface->h;
             return opengl_control_message(h, AV_APP_TO_DEV_WINDOW_SIZE, &message, sizeof(AVDeviceRect));
             }
         }
     }
     return 0;
 }
 
 static int av_cold opengl_sdl_create_window(AVFormatContext *h)
 {
     int ret;
     char buffer[100];
     OpenGLContext *opengl = h->priv_data;
     AVDeviceRect message;
     if (SDL_Init(SDL_INIT_VIDEO)) {
         av_log(opengl, AV_LOG_ERROR, "Unable to initialize SDL: %s\n", SDL_GetError());
         return AVERROR_EXTERNAL;
     }
     if ((ret = opengl_sdl_recreate_window(opengl, opengl->width, opengl->height)) < 0)
         return ret;
     av_log(opengl, AV_LOG_INFO, "SDL driver: '%s'.\n", SDL_VideoDriverName(buffer, sizeof(buffer)));
     message.width = opengl->surface->w;
     message.height = opengl->surface->h;

     SDL_WM_SetCaption(opengl->window_title, NULL);

     opengl_control_message(h, AV_APP_TO_DEV_WINDOW_SIZE, &message, sizeof(AVDeviceRect));
     return 0;
 }
 
 static int av_cold opengl_sdl_load_procedures(OpenGLContext *opengl)
 {
     FFOpenGLFunctions *procs = &opengl->glprocs;
 
 #define LOAD_OPENGL_FUN(name, type) \
     procs->name = (type)SDL_GL_GetProcAddress(#name); \
     if (!procs->name) { \
         av_log(opengl, AV_LOG_ERROR, "Cannot load OpenGL function: '%s'\n", #name); \
         return AVERROR(ENOSYS); \
     }
 
     LOAD_OPENGL_FUN(glActiveTexture, FF_PFNGLACTIVETEXTUREPROC)
     LOAD_OPENGL_FUN(glGenBuffers, FF_PFNGLGENBUFFERSPROC)
     LOAD_OPENGL_FUN(glDeleteBuffers, FF_PFNGLDELETEBUFFERSPROC)
     LOAD_OPENGL_FUN(glBufferData, FF_PFNGLBUFFERDATAPROC)
     LOAD_OPENGL_FUN(glBindBuffer, FF_PFNGLBINDBUFFERPROC)
     LOAD_OPENGL_FUN(glGetAttribLocation, FF_PFNGLGETATTRIBLOCATIONPROC)
     LOAD_OPENGL_FUN(glGetUniformLocation, FF_PFNGLGETUNIFORMLOCATIONPROC)
     LOAD_OPENGL_FUN(glUniform1f, FF_PFNGLUNIFORM1FPROC)
     LOAD_OPENGL_FUN(glUniform1i, FF_PFNGLUNIFORM1IPROC)
     LOAD_OPENGL_FUN(glUniformMatrix4fv, FF_PFNGLUNIFORMMATRIX4FVPROC)
     LOAD_OPENGL_FUN(glCreateProgram, FF_PFNGLCREATEPROGRAMPROC)
     LOAD_OPENGL_FUN(glDeleteProgram, FF_PFNGLDELETEPROGRAMPROC)
     LOAD_OPENGL_FUN(glUseProgram, FF_PFNGLUSEPROGRAMPROC)
     LOAD_OPENGL_FUN(glLinkProgram, FF_PFNGLLINKPROGRAMPROC)
     LOAD_OPENGL_FUN(glGetProgramiv, FF_PFNGLGETPROGRAMIVPROC)
     LOAD_OPENGL_FUN(glGetProgramInfoLog, FF_PFNGLGETPROGRAMINFOLOGPROC)
     LOAD_OPENGL_FUN(glAttachShader, FF_PFNGLATTACHSHADERPROC)
     LOAD_OPENGL_FUN(glCreateShader, FF_PFNGLCREATESHADERPROC)
     LOAD_OPENGL_FUN(glDeleteShader, FF_PFNGLDELETESHADERPROC)
     LOAD_OPENGL_FUN(glCompileShader, FF_PFNGLCOMPILESHADERPROC)
     LOAD_OPENGL_FUN(glShaderSource, FF_PFNGLSHADERSOURCEPROC)
     LOAD_OPENGL_FUN(glGetShaderiv, FF_PFNGLGETSHADERIVPROC)
     LOAD_OPENGL_FUN(glGetShaderInfoLog, FF_PFNGLGETSHADERINFOLOGPROC)
     LOAD_OPENGL_FUN(glEnableVertexAttribArray, FF_PFNGLENABLEVERTEXATTRIBARRAYPROC)
     LOAD_OPENGL_FUN(glVertexAttribPointer, FF_PFNGLVERTEXATTRIBPOINTERPROC)
 
     return 0;
 
 #undef LOAD_OPENGL_FUN
 }
 #endif /* HAVE_SDL */
 
 #if defined(__APPLE__)
 static int av_cold opengl_load_procedures(OpenGLContext *opengl)
 {
     FFOpenGLFunctions *procs = &opengl->glprocs;
 

 #if HAVE_SDL
     if (!opengl->no_window)
         return opengl_sdl_load_procedures(opengl);
 #endif
 

     procs->glActiveTexture = glActiveTexture;
     procs->glGenBuffers = glGenBuffers;
     procs->glDeleteBuffers = glDeleteBuffers;
     procs->glBufferData = glBufferData;
     procs->glBindBuffer = glBindBuffer;
     procs->glGetAttribLocation = glGetAttribLocation;
     procs->glGetUniformLocation = glGetUniformLocation;
     procs->glUniform1f = glUniform1f;
     procs->glUniform1i = glUniform1i;
     procs->glUniformMatrix4fv = glUniformMatrix4fv;
     procs->glCreateProgram = glCreateProgram;
     procs->glDeleteProgram = glDeleteProgram;
     procs->glUseProgram = glUseProgram;
     procs->glLinkProgram = glLinkProgram;
     procs->glGetProgramiv = glGetProgramiv;
     procs->glGetProgramInfoLog = glGetProgramInfoLog;
     procs->glAttachShader = glAttachShader;
     procs->glCreateShader = glCreateShader;
     procs->glDeleteShader = glDeleteShader;
     procs->glCompileShader = glCompileShader;
     procs->glShaderSource = glShaderSource;
     procs->glGetShaderiv = glGetShaderiv;
     procs->glGetShaderInfoLog = glGetShaderInfoLog;
     procs->glEnableVertexAttribArray = glEnableVertexAttribArray;
     procs->glVertexAttribPointer = (FF_PFNGLVERTEXATTRIBPOINTERPROC) glVertexAttribPointer;
     return 0;
 }
 #else
 static int av_cold opengl_load_procedures(OpenGLContext *opengl)
 {
     FFOpenGLFunctions *procs = &opengl->glprocs;
 
 #if HAVE_GLXGETPROCADDRESS
 #define SelectedGetProcAddress glXGetProcAddress
 #elif HAVE_WGLGETPROCADDRESS
 #define SelectedGetProcAddress wglGetProcAddress
 #endif
 
 #define LOAD_OPENGL_FUN(name, type) \
     procs->name = (type)SelectedGetProcAddress(#name); \
     if (!procs->name) { \
         av_log(opengl, AV_LOG_ERROR, "Cannot load OpenGL function: '%s'\n", #name); \
         return AVERROR(ENOSYS); \
     }
 

 #if HAVE_SDL
     if (!opengl->no_window)
         return opengl_sdl_load_procedures(opengl);
 #endif
 

     LOAD_OPENGL_FUN(glActiveTexture, FF_PFNGLACTIVETEXTUREPROC)
     LOAD_OPENGL_FUN(glGenBuffers, FF_PFNGLGENBUFFERSPROC)
     LOAD_OPENGL_FUN(glDeleteBuffers, FF_PFNGLDELETEBUFFERSPROC)
     LOAD_OPENGL_FUN(glBufferData, FF_PFNGLBUFFERDATAPROC)
     LOAD_OPENGL_FUN(glBindBuffer, FF_PFNGLBINDBUFFERPROC)
     LOAD_OPENGL_FUN(glGetAttribLocation, FF_PFNGLGETATTRIBLOCATIONPROC)
     LOAD_OPENGL_FUN(glGetUniformLocation, FF_PFNGLGETUNIFORMLOCATIONPROC)
     LOAD_OPENGL_FUN(glUniform1f, FF_PFNGLUNIFORM1FPROC)
     LOAD_OPENGL_FUN(glUniform1i, FF_PFNGLUNIFORM1IPROC)
     LOAD_OPENGL_FUN(glUniformMatrix4fv, FF_PFNGLUNIFORMMATRIX4FVPROC)
     LOAD_OPENGL_FUN(glCreateProgram, FF_PFNGLCREATEPROGRAMPROC)
     LOAD_OPENGL_FUN(glDeleteProgram, FF_PFNGLDELETEPROGRAMPROC)
     LOAD_OPENGL_FUN(glUseProgram, FF_PFNGLUSEPROGRAMPROC)
     LOAD_OPENGL_FUN(glLinkProgram, FF_PFNGLLINKPROGRAMPROC)
     LOAD_OPENGL_FUN(glGetProgramiv, FF_PFNGLGETPROGRAMIVPROC)
     LOAD_OPENGL_FUN(glGetProgramInfoLog, FF_PFNGLGETPROGRAMINFOLOGPROC)
     LOAD_OPENGL_FUN(glAttachShader, FF_PFNGLATTACHSHADERPROC)
     LOAD_OPENGL_FUN(glCreateShader, FF_PFNGLCREATESHADERPROC)
     LOAD_OPENGL_FUN(glDeleteShader, FF_PFNGLDELETESHADERPROC)
     LOAD_OPENGL_FUN(glCompileShader, FF_PFNGLCOMPILESHADERPROC)
     LOAD_OPENGL_FUN(glShaderSource, FF_PFNGLSHADERSOURCEPROC)
     LOAD_OPENGL_FUN(glGetShaderiv, FF_PFNGLGETSHADERIVPROC)
     LOAD_OPENGL_FUN(glGetShaderInfoLog, FF_PFNGLGETSHADERINFOLOGPROC)
     LOAD_OPENGL_FUN(glEnableVertexAttribArray, FF_PFNGLENABLEVERTEXATTRIBARRAYPROC)
     LOAD_OPENGL_FUN(glVertexAttribPointer, FF_PFNGLVERTEXATTRIBPOINTERPROC)
 
     return 0;
 
 #undef SelectedGetProcAddress
 #undef LOAD_OPENGL_FUN
 }
 #endif
 

 static void opengl_make_identity(float matrix[16])

 {
     memset(matrix, 0, 16 * sizeof(float));
     matrix[0] = matrix[5] = matrix[10] = matrix[15] = 1.0f;
 }
 

 static void opengl_make_ortho(float matrix[16], float left, float right,
                               float bottom, float top, float nearZ, float farZ)

 {
     float ral = right + left;
     float rsl = right - left;
     float tab = top + bottom;
     float tsb = top - bottom;
     float fan = farZ + nearZ;
     float fsn = farZ - nearZ;
 
     memset(matrix, 0, 16 * sizeof(float));
     matrix[0] = 2.0f / rsl;
     matrix[5] = 2.0f / tsb;
     matrix[10] = -2.0f / fsn;
     matrix[12] = -ral / rsl;
     matrix[13] = -tab / tsb;
     matrix[14] = -fan / fsn;
     matrix[15] = 1.0f;
 }
 
 static av_cold int opengl_read_limits(OpenGLContext *opengl)
 {
     static const struct{
         const char *extention;
         int major;
         int minor;
     } required_extensions[] = {
         { "GL_ARB_multitexture",         1, 3 },
         { "GL_ARB_vertex_buffer_object", 1, 5 }, //GLX_ARB_vertex_buffer_object
         { "GL_ARB_vertex_shader",        2, 0 },
         { "GL_ARB_fragment_shader",      2, 0 },
         { "GL_ARB_shader_objects",       2, 0 },
         { NULL,                          0, 0 }
     };
     int i, major, minor;
     const char *extensions, *version;
 
     version = glGetString(GL_VERSION);
     extensions = glGetString(GL_EXTENSIONS);
 
     av_log(opengl, AV_LOG_DEBUG, "OpenGL version: %s\n", version);
     sscanf(version, "%d.%d", &major, &minor);
 
     for (i = 0; required_extensions[i].extention; i++) {
         if (major < required_extensions[i].major &&
             (major == required_extensions[i].major && minor < required_extensions[i].minor) &&
             !strstr(extensions, required_extensions[i].extention)) {
             av_log(opengl, AV_LOG_ERROR, "Required extension %s is not supported.\n",
                    required_extensions[i].extention);
             av_log(opengl, AV_LOG_DEBUG, "Supported extensions are: %s\n", extensions);
             return AVERROR(ENOSYS);
         }
     }
     glGetIntegerv(GL_MAX_TEXTURE_SIZE, &opengl->max_texture_size);
     glGetIntegerv(GL_MAX_VIEWPORT_DIMS, &opengl->max_viewport_width);
     opengl->non_pow_2_textures = major >= 2 || strstr(extensions, "GL_ARB_texture_non_power_of_two");

 #if defined(GL_ES_VERSION_2_0)
     opengl->unpack_subimage = !!strstr(extensions, "GL_EXT_unpack_subimage");
 #else
     opengl->unpack_subimage = 1;
 #endif

 
     av_log(opengl, AV_LOG_DEBUG, "Non Power of 2 textures support: %s\n", opengl->non_pow_2_textures ? "Yes" : "No");

     av_log(opengl, AV_LOG_DEBUG, "Unpack Subimage extension support: %s\n", opengl->unpack_subimage ? "Yes" : "No");

     av_log(opengl, AV_LOG_DEBUG, "Max texture size: %dx%d\n", opengl->max_texture_size, opengl->max_texture_size);
     av_log(opengl, AV_LOG_DEBUG, "Max viewport size: %dx%d\n",
            opengl->max_viewport_width, opengl->max_viewport_height);
 
     OPENGL_ERROR_CHECK(opengl);
     return 0;
   fail:
     return AVERROR_EXTERNAL;
 }
 

 static const char* opengl_get_fragment_shader_code(enum AVPixelFormat format)

 {

     int i;
     for (i = 0; i < FF_ARRAY_ELEMS(opengl_format_desc); i++) {
         if (opengl_format_desc[i].fixel_format == format)
             return *opengl_format_desc[i].fragment_shader;

     }
     return NULL;
 }
 

 static int opengl_type_size(GLenum type)

 {
     switch(type) {
     case GL_UNSIGNED_SHORT:
     case FF_GL_UNSIGNED_SHORT_1_5_5_5_REV:
     case GL_UNSIGNED_SHORT_5_6_5:
         return 2;
     case GL_UNSIGNED_BYTE:
     case FF_GL_UNSIGNED_BYTE_3_3_2:
     case FF_GL_UNSIGNED_BYTE_2_3_3_REV:
     default:
         break;
     }
     return 1;
 }
 
 static av_cold void opengl_get_texture_params(OpenGLContext *opengl)
 {

     int i;
     for (i = 0; i < FF_ARRAY_ELEMS(opengl_format_desc); i++) {
         if (opengl_format_desc[i].fixel_format == opengl->pix_fmt) {
             opengl->format = opengl_format_desc[i].format;
             opengl->type = opengl_format_desc[i].type;
             break;
         }

     }
 }
 
 static void opengl_compute_display_area(AVFormatContext *s)
 {
     AVRational sar, dar; /* sample and display aspect ratios */
     OpenGLContext *opengl = s->priv_data;
     AVStream *st = s->streams[0];
     AVCodecContext *encctx = st->codec;
 
     /* compute overlay width and height from the codec context information */
     sar = st->sample_aspect_ratio.num ? st->sample_aspect_ratio : (AVRational){ 1, 1 };
     dar = av_mul_q(sar, (AVRational){ encctx->width, encctx->height });
 
     /* we suppose the screen has a 1/1 sample aspect ratio */
     /* fit in the window */
     if (av_cmp_q(dar, (AVRational){ opengl->window_width, opengl->window_height }) > 0) {
         /* fit in width */
         opengl->picture_width = opengl->window_width;
         opengl->picture_height = av_rescale(opengl->picture_width, dar.den, dar.num);
     } else {
         /* fit in height */
         opengl->picture_height = opengl->window_height;
         opengl->picture_width = av_rescale(opengl->picture_height, dar.num, dar.den);
     }
 }
 
 static av_cold void opengl_get_texture_size(OpenGLContext *opengl, int in_width, int in_height,
                                             int *out_width, int *out_height)
 {
     if (opengl->non_pow_2_textures) {
         *out_width = in_width;
         *out_height = in_height;
     } else {
         int max = FFMIN(FFMAX(in_width, in_height), opengl->max_texture_size);
         unsigned power_of_2 = 1;
         while (power_of_2 < max)
             power_of_2 *= 2;
         *out_height = power_of_2;
         *out_width = power_of_2;
         av_log(opengl, AV_LOG_DEBUG, "Texture size calculated from %dx%d into %dx%d\n",
                in_width, in_height, *out_width, *out_height);
     }
 }
 
 static av_cold void opengl_fill_color_map(OpenGLContext *opengl)
 {
     const AVPixFmtDescriptor *desc;
     int shift;
     enum AVPixelFormat pix_fmt = opengl->pix_fmt;
 
     /* We need order of components, not exact position, some minor HACKs here */
     if (pix_fmt == AV_PIX_FMT_RGB565 || pix_fmt == AV_PIX_FMT_BGR555 ||
         pix_fmt == AV_PIX_FMT_BGR8   || pix_fmt == AV_PIX_FMT_RGB8)
         pix_fmt = AV_PIX_FMT_RGB24;
     else if (pix_fmt == AV_PIX_FMT_BGR565 || pix_fmt == AV_PIX_FMT_RGB555)
         pix_fmt = AV_PIX_FMT_BGR24;
 
     desc = av_pix_fmt_desc_get(pix_fmt);
     if (!(desc->flags & AV_PIX_FMT_FLAG_RGB))
         return;
 
 #define FILL_COMPONENT(i) { \
         shift = desc->comp[i].depth_minus1 >> 3; \
         opengl->color_map[(i << 2) + ((desc->comp[i].offset_plus1 - 1) >> shift)] = 1.0; \
     }
 
     memset(opengl->color_map, 0, sizeof(opengl->color_map));
     FILL_COMPONENT(0);
     FILL_COMPONENT(1);
     FILL_COMPONENT(2);
     if (desc->flags & AV_PIX_FMT_FLAG_ALPHA)
         FILL_COMPONENT(3);
 
 #undef FILL_COMPONENT
 }
 
 static av_cold GLuint opengl_load_shader(OpenGLContext *opengl, GLenum type, const char *source)
 {
     GLuint shader = opengl->glprocs.glCreateShader(type);
     GLint result;
     if (!shader) {
         av_log(opengl, AV_LOG_ERROR, "glCreateShader() failed\n");
         return 0;
     }
     opengl->glprocs.glShaderSource(shader, 1, &source, NULL);
     opengl->glprocs.glCompileShader(shader);
 
     opengl->glprocs.glGetShaderiv(shader, FF_GL_COMPILE_STATUS, &result);
     if (!result) {
         char *log;
         opengl->glprocs.glGetShaderiv(shader, FF_GL_INFO_LOG_LENGTH, &result);
         if (result) {
             if ((log = av_malloc(result))) {
                 opengl->glprocs.glGetShaderInfoLog(shader, result, NULL, log);
                 av_log(opengl, AV_LOG_ERROR, "Compile error: %s\n", log);
                 av_free(log);
             }
         }
         goto fail;
     }
     OPENGL_ERROR_CHECK(opengl);
     return shader;
   fail:
     opengl->glprocs.glDeleteShader(shader);
     return 0;
 }
 
 static av_cold int opengl_compile_shaders(OpenGLContext *opengl, enum AVPixelFormat pix_fmt)
 {
     GLint result;
     const char *fragment_shader_code = opengl_get_fragment_shader_code(pix_fmt);
 
     if (!fragment_shader_code) {
         av_log(opengl, AV_LOG_ERROR, "Provided pixel format '%s' is not supported\n",
                av_get_pix_fmt_name(pix_fmt));
         return AVERROR(EINVAL);
     }
 

     opengl->vertex_shader = opengl_load_shader(opengl, FF_GL_VERTEX_SHADER,
                                                FF_OPENGL_VERTEX_SHADER);
     if (!opengl->vertex_shader) {

         av_log(opengl, AV_LOG_ERROR, "Vertex shader loading failed.\n");
         goto fail;
     }

     opengl->fragment_shader = opengl_load_shader(opengl, FF_GL_FRAGMENT_SHADER,
                                                  fragment_shader_code);
     if (!opengl->fragment_shader) {

         av_log(opengl, AV_LOG_ERROR, "Fragment shader loading failed.\n");
         goto fail;
     }
 
     opengl->program = opengl->glprocs.glCreateProgram();
     if (!opengl->program)
         goto fail;
 

     opengl->glprocs.glAttachShader(opengl->program, opengl->vertex_shader);
     opengl->glprocs.glAttachShader(opengl->program, opengl->fragment_shader);

     opengl->glprocs.glLinkProgram(opengl->program);
 
     opengl->glprocs.glGetProgramiv(opengl->program, FF_GL_LINK_STATUS, &result);
     if (!result) {
         char *log;
         opengl->glprocs.glGetProgramiv(opengl->program, FF_GL_INFO_LOG_LENGTH, &result);
         if (result) {
             log = av_malloc(result);
             if (!log)
                 goto fail;
             opengl->glprocs.glGetProgramInfoLog(opengl->program, result, NULL, log);
             av_log(opengl, AV_LOG_ERROR, "Link error: %s\n", log);
             av_free(log);
         }
         goto fail;
     }
 
     opengl->position_attrib = opengl->glprocs.glGetAttribLocation(opengl->program, "a_position");
     opengl->texture_coords_attrib = opengl->glprocs.glGetAttribLocation(opengl->program, "a_textureCoords");
     opengl->projection_matrix_location = opengl->glprocs.glGetUniformLocation(opengl->program, "u_projectionMatrix");
     opengl->model_view_matrix_location = opengl->glprocs.glGetUniformLocation(opengl->program, "u_modelViewMatrix");
     opengl->color_map_location = opengl->glprocs.glGetUniformLocation(opengl->program, "u_colorMap");
     opengl->texture_location[0] = opengl->glprocs.glGetUniformLocation(opengl->program, "u_texture0");
     opengl->texture_location[1] = opengl->glprocs.glGetUniformLocation(opengl->program, "u_texture1");
     opengl->texture_location[2] = opengl->glprocs.glGetUniformLocation(opengl->program, "u_texture2");
     opengl->texture_location[3] = opengl->glprocs.glGetUniformLocation(opengl->program, "u_texture3");
     opengl->chroma_div_w_location = opengl->glprocs.glGetUniformLocation(opengl->program, "u_chroma_div_w");
     opengl->chroma_div_h_location = opengl->glprocs.glGetUniformLocation(opengl->program, "u_chroma_div_h");
 
     OPENGL_ERROR_CHECK(opengl);
     return 0;
   fail:

     opengl->glprocs.glDeleteShader(opengl->vertex_shader);
     opengl->glprocs.glDeleteShader(opengl->fragment_shader);

     opengl->glprocs.glDeleteProgram(opengl->program);

     opengl->fragment_shader = opengl->vertex_shader = opengl->program = 0;

     return AVERROR_EXTERNAL;
 }
 
 static av_cold int opengl_configure_texture(OpenGLContext *opengl, GLuint texture,
                                             GLsizei width, GLsizei height)
 {
     if (texture) {
         int new_width, new_height;
         opengl_get_texture_size(opengl, width, height, &new_width, &new_height);
         glBindTexture(GL_TEXTURE_2D, texture);
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
         glTexImage2D(GL_TEXTURE_2D, 0, opengl->format, new_width, new_height, 0,
                      opengl->format, opengl->type, NULL);
         OPENGL_ERROR_CHECK(NULL);
     }
     return 0;
   fail:
     return AVERROR_EXTERNAL;
 }
 
 static av_cold int opengl_prepare_vertex(AVFormatContext *s)
 {
     OpenGLContext *opengl = s->priv_data;
     int tex_w, tex_h;
 
     if (opengl->window_width > opengl->max_viewport_width || opengl->window_height > opengl->max_viewport_height) {
         opengl->window_width = FFMAX(opengl->window_width, opengl->max_viewport_width);
         opengl->window_height = FFMAX(opengl->window_height, opengl->max_viewport_height);
         av_log(opengl, AV_LOG_WARNING, "Too big viewport requested, limited to %dx%d", opengl->window_width, opengl->window_height);
     }
     glViewport(0, 0, opengl->window_width, opengl->window_height);
     opengl_make_ortho(opengl->projection_matrix,
                       - (float)opengl->window_width  / 2.0f, (float)opengl->window_width  / 2.0f,
                       - (float)opengl->window_height / 2.0f, (float)opengl->window_height / 2.0f,
                       1.0f, -1.0f);
     opengl_make_identity(opengl->model_view_matrix);
 
     opengl_compute_display_area(s);
 
     opengl->vertex[0].z = opengl->vertex[1].z = opengl->vertex[2].z = opengl->vertex[3].z = 0.0f;
     opengl->vertex[0].x = opengl->vertex[1].x = - (float)opengl->picture_width / 2.0f;
     opengl->vertex[2].x = opengl->vertex[3].x =   (float)opengl->picture_width / 2.0f;
     opengl->vertex[1].y = opengl->vertex[2].y = - (float)opengl->picture_height / 2.0f;
     opengl->vertex[0].y = opengl->vertex[3].y =   (float)opengl->picture_height / 2.0f;
 
     opengl_get_texture_size(opengl, opengl->width, opengl->height, &tex_w, &tex_h);
 
     opengl->vertex[0].s0 = 0.0f;
     opengl->vertex[0].t0 = 0.0f;
     opengl->vertex[1].s0 = 0.0f;
     opengl->vertex[1].t0 = (float)opengl->height / (float)tex_h;
     opengl->vertex[2].s0 = (float)opengl->width  / (float)tex_w;
     opengl->vertex[2].t0 = (float)opengl->height / (float)tex_h;
     opengl->vertex[3].s0 = (float)opengl->width  / (float)tex_w;
     opengl->vertex[3].t0 = 0.0f;
 
     opengl->glprocs.glBindBuffer(FF_GL_ARRAY_BUFFER, opengl->vertex_buffer);
     opengl->glprocs.glBufferData(FF_GL_ARRAY_BUFFER, sizeof(opengl->vertex), opengl->vertex, FF_GL_STATIC_DRAW);
     opengl->glprocs.glBindBuffer(FF_GL_ARRAY_BUFFER, 0);
     OPENGL_ERROR_CHECK(opengl);
     return 0;
   fail:
     return AVERROR_EXTERNAL;
 }
 
 static int opengl_prepare(OpenGLContext *opengl)
 {
     int i;
     opengl->glprocs.glUseProgram(opengl->program);
     opengl->glprocs.glUniformMatrix4fv(opengl->projection_matrix_location, 1, GL_FALSE, opengl->projection_matrix);
     opengl->glprocs.glUniformMatrix4fv(opengl->model_view_matrix_location, 1, GL_FALSE, opengl->model_view_matrix);
     for (i = 0; i < 4; i++)
         if (opengl->texture_location[i] != -1) {
             opengl->glprocs.glActiveTexture(GL_TEXTURE0 + i);
             glBindTexture(GL_TEXTURE_2D, opengl->texture_name[i]);
             opengl->glprocs.glUniform1i(opengl->texture_location[i], i);
         }
     if (opengl->color_map_location != -1)
         opengl->glprocs.glUniformMatrix4fv(opengl->color_map_location, 1, GL_FALSE, opengl->color_map);
     if (opengl->chroma_div_h_location != -1)
         opengl->glprocs.glUniform1f(opengl->chroma_div_h_location, opengl->chroma_div_h);
     if (opengl->chroma_div_w_location != -1)
         opengl->glprocs.glUniform1f(opengl->chroma_div_w_location, opengl->chroma_div_w);
 
     OPENGL_ERROR_CHECK(opengl);
     return 0;
   fail:
     return AVERROR_EXTERNAL;
 }
 

 static int opengl_create_window(AVFormatContext *h)
 {
     OpenGLContext *opengl = h->priv_data;
     int ret;
 
     if (!opengl->no_window) {
 #if HAVE_SDL
         if ((ret = opengl_sdl_create_window(h)) < 0) {
             av_log(opengl, AV_LOG_ERROR, "Cannot create default SDL window.\n");
             return ret;
         }
 #else
         av_log(opengl, AV_LOG_ERROR, "FFmpeg is compiled without SDL. Cannot create default window.\n");
         return AVERROR(ENOSYS);
 #endif
     } else {
         if ((ret = avdevice_dev_to_app_control_message(h, AV_DEV_TO_APP_CREATE_WINDOW_BUFFER, NULL , 0)) < 0) {
             av_log(opengl, AV_LOG_ERROR, "Application failed to create window buffer.\n");
             return ret;
         }
         if ((ret = avdevice_dev_to_app_control_message(h, AV_DEV_TO_APP_PREPARE_WINDOW_BUFFER, NULL , 0)) < 0) {
             av_log(opengl, AV_LOG_ERROR, "Application failed to prepare window buffer.\n");
             return ret;
         }
     }
     return 0;
 }
 
 static int opengl_release_window(AVFormatContext *h)
 {
     int ret;
     OpenGLContext *opengl = h->priv_data;
     if (!opengl->no_window) {
 #if HAVE_SDL
         SDL_Quit();
 #endif

     } else if ((ret = avdevice_dev_to_app_control_message(h, AV_DEV_TO_APP_DESTROY_WINDOW_BUFFER, NULL , 0)) < 0) {

         av_log(opengl, AV_LOG_ERROR, "Application failed to release window buffer.\n");
         return ret;
     }
     return 0;
 }
 

 static av_cold int opengl_write_trailer(AVFormatContext *h)
 {
     OpenGLContext *opengl = h->priv_data;
 
     if (opengl->no_window &&
         avdevice_dev_to_app_control_message(h, AV_DEV_TO_APP_PREPARE_WINDOW_BUFFER, NULL , 0) < 0)
         av_log(opengl, AV_LOG_ERROR, "Application failed to prepare window buffer.\n");
 

     opengl_deinit_context(opengl);

     opengl_release_window(h);

 
     return 0;
 }
 
 static av_cold int opengl_init_context(OpenGLContext *opengl)
 {
     int i, ret;
     const AVPixFmtDescriptor *desc;
 
     if ((ret = opengl_compile_shaders(opengl, opengl->pix_fmt)) < 0)
         goto fail;
 
     desc = av_pix_fmt_desc_get(opengl->pix_fmt);
     av_assert0(desc->nb_components > 0 && desc->nb_components <= 4);
     glGenTextures(desc->nb_components, opengl->texture_name);
 
     opengl->glprocs.glGenBuffers(2, &opengl->index_buffer);
     if (!opengl->index_buffer || !opengl->vertex_buffer) {
         av_log(opengl, AV_LOG_ERROR, "Buffer generation failed.\n");
         ret = AVERROR_EXTERNAL;
         goto fail;
     }
 
     opengl_configure_texture(opengl, opengl->texture_name[0], opengl->width, opengl->height);
     if (desc->nb_components > 1) {
         int has_alpha = desc->flags & AV_PIX_FMT_FLAG_ALPHA;
         int num_planes = desc->nb_components - (has_alpha ? 1 : 0);
         if (opengl->non_pow_2_textures) {
             opengl->chroma_div_w = 1.0f;
             opengl->chroma_div_h = 1.0f;
         } else {
             opengl->chroma_div_w = 1 << desc->log2_chroma_w;
             opengl->chroma_div_h = 1 << desc->log2_chroma_h;
         }
         for (i = 1; i < num_planes; i++)
             if (opengl->non_pow_2_textures)
                 opengl_configure_texture(opengl, opengl->texture_name[i],
                         FF_CEIL_RSHIFT(opengl->width, desc->log2_chroma_w),
                         FF_CEIL_RSHIFT(opengl->height, desc->log2_chroma_h));
             else
                 opengl_configure_texture(opengl, opengl->texture_name[i], opengl->width, opengl->height);
         if (has_alpha)
             opengl_configure_texture(opengl, opengl->texture_name[3], opengl->width, opengl->height);
     }
 
     opengl->glprocs.glBindBuffer(FF_GL_ELEMENT_ARRAY_BUFFER, opengl->index_buffer);
     opengl->glprocs.glBufferData(FF_GL_ELEMENT_ARRAY_BUFFER, sizeof(g_index), g_index, FF_GL_STATIC_DRAW);
     opengl->glprocs.glBindBuffer(FF_GL_ELEMENT_ARRAY_BUFFER, 0);
 
     glEnable(GL_BLEND);
     glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 
     glClearColor((float)opengl->background[0] / 255.0f, (float)opengl->background[1] / 255.0f,
                  (float)opengl->background[2] / 255.0f, 1.0f);
 
     ret = AVERROR_EXTERNAL;
     OPENGL_ERROR_CHECK(opengl);
 
     return 0;
   fail:
     return ret;
 }
 
 static av_cold int opengl_write_header(AVFormatContext *h)
 {
     OpenGLContext *opengl = h->priv_data;
     AVStream *st;
     int ret;
 
     if (h->nb_streams != 1 ||
         h->streams[0]->codec->codec_type != AVMEDIA_TYPE_VIDEO ||
         h->streams[0]->codec->codec_id != AV_CODEC_ID_RAWVIDEO) {
         av_log(opengl, AV_LOG_ERROR, "Only a single video stream is supported.\n");
         return AVERROR(EINVAL);
     }
     st = h->streams[0];
     opengl->width = st->codec->width;
     opengl->height = st->codec->height;
     opengl->pix_fmt = st->codec->pix_fmt;
 
     if (!opengl->window_title && !opengl->no_window)
         opengl->window_title = av_strdup(h->filename);
 

     if ((ret = opengl_create_window(h)))

         goto fail;
 
     if ((ret = opengl_read_limits(opengl)) < 0)
         goto fail;
 
     if (opengl->width > opengl->max_texture_size || opengl->height > opengl->max_texture_size) {
         av_log(opengl, AV_LOG_ERROR, "Too big picture %dx%d, max supported size is %dx%d\n",
                opengl->width, opengl->height, opengl->max_texture_size, opengl->max_texture_size);
         ret = AVERROR(EINVAL);
         goto fail;
     }
 

     if ((ret = opengl_load_procedures(opengl)) < 0)

         goto fail;
 
     opengl_fill_color_map(opengl);
     opengl_get_texture_params(opengl);
 
     if ((ret = opengl_init_context(opengl)) < 0)
         goto fail;
 
     if ((ret = opengl_prepare_vertex(h)) < 0)
         goto fail;
 
     glClear(GL_COLOR_BUFFER_BIT);
 
 #if HAVE_SDL
     if (!opengl->no_window)
         SDL_GL_SwapBuffers();
 #endif
     if (opengl->no_window &&
         (ret = avdevice_dev_to_app_control_message(h, AV_DEV_TO_APP_DISPLAY_WINDOW_BUFFER, NULL , 0)) < 0) {
         av_log(opengl, AV_LOG_ERROR, "Application failed to display window buffer.\n");
         goto fail;
     }
 
     ret = AVERROR_EXTERNAL;
     OPENGL_ERROR_CHECK(opengl);
     return 0;
 
   fail:
     opengl_write_trailer(h);
     return ret;
 }
 
 static uint8_t* opengl_get_plane_pointer(OpenGLContext *opengl, AVPacket *pkt, int comp_index,
                                          const AVPixFmtDescriptor *desc)
 {
     uint8_t *data = pkt->data;
     int wordsize = opengl_type_size(opengl->type);
     int width_chroma = FF_CEIL_RSHIFT(opengl->width, desc->log2_chroma_w);
     int height_chroma = FF_CEIL_RSHIFT(opengl->height, desc->log2_chroma_h);
     int plane = desc->comp[comp_index].plane;
 
     switch(plane) {
     case 0:
         break;
     case 1:
         data += opengl->width * opengl->height * wordsize;
         break;
     case 2:
         data += opengl->width * opengl->height * wordsize;
         data += width_chroma * height_chroma * wordsize;
         break;
     case 3:
         data += opengl->width * opengl->height * wordsize;
         data += 2 * width_chroma * height_chroma * wordsize;
         break;
     default:
         return NULL;
     }
     return data;
 }
 

 #define LOAD_TEXTURE_DATA(comp_index, sub)                                                  \
 {                                                                                           \
     int width = sub ? FF_CEIL_RSHIFT(opengl->width, desc->log2_chroma_w) : opengl->width;   \
     int height = sub ? FF_CEIL_RSHIFT(opengl->height, desc->log2_chroma_h): opengl->height; \
     uint8_t *data;                                                                          \
     int plane = desc->comp[comp_index].plane;                                               \
                                                                                             \
     glBindTexture(GL_TEXTURE_2D, opengl->texture_name[comp_index]);                         \
     if (!is_pkt) {                                                                          \
         GLint length = ((AVFrame *)input)->linesize[plane];                                 \
         int bytes_per_pixel = opengl_type_size(opengl->type);                               \
         if (!(desc->flags & AV_PIX_FMT_FLAG_PLANAR))                                        \
             bytes_per_pixel *= desc->nb_components;                                         \
         data = ((AVFrame *)input)->data[plane];                                             \
         if (!(length % bytes_per_pixel) &&                                                  \
             (opengl->unpack_subimage || ((length / bytes_per_pixel) == width))) {           \
             length /= bytes_per_pixel;                                                      \
             if (length != width)                                                            \
                 glPixelStorei(FF_GL_UNPACK_ROW_LENGTH, length);                             \
             glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height,                          \
                             opengl->format, opengl->type, data);                            \
             if (length != width)                                                            \
                 glPixelStorei(FF_GL_UNPACK_ROW_LENGTH, 0);                                  \
         } else {                                                                            \
             int h;                                                                          \
             for (h = 0; h < height; h++) {                                                  \
                 glTexSubImage2D(GL_TEXTURE_2D, 0, 0, h, width, 1,                           \
                                 opengl->format, opengl->type, data);                        \
                 data += length;                                                             \
             }                                                                               \
         }                                                                                   \
     } else {                                                                                \
         data = opengl_get_plane_pointer(opengl, input, comp_index, desc);                   \
         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height,                              \
                         opengl->format, opengl->type, data);                                \
     }                                                                                       \
 }
 
 static int opengl_draw(AVFormatContext *h, void *input, int repaint, int is_pkt)

 {
     OpenGLContext *opengl = h->priv_data;
     enum AVPixelFormat pix_fmt = h->streams[0]->codec->pix_fmt;
     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
     int ret;
 
 #if HAVE_SDL
     if (!opengl->no_window && (ret = opengl_sdl_process_events(h)) < 0)
         goto fail;
 #endif
     if (opengl->no_window &&
         (ret = avdevice_dev_to_app_control_message(h, AV_DEV_TO_APP_PREPARE_WINDOW_BUFFER, NULL , 0)) < 0) {
         av_log(opengl, AV_LOG_ERROR, "Application failed to prepare window buffer.\n");
         goto fail;
     }
 
     glClear(GL_COLOR_BUFFER_BIT);
 
     if (!repaint) {

         if (is_pkt)
             glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

         LOAD_TEXTURE_DATA(0, 0)

         if (desc->flags & AV_PIX_FMT_FLAG_PLANAR) {

             LOAD_TEXTURE_DATA(1, 1)
             LOAD_TEXTURE_DATA(2, 1)
             if (desc->flags & AV_PIX_FMT_FLAG_ALPHA)
                 LOAD_TEXTURE_DATA(3, 0)

         }
     }
     ret = AVERROR_EXTERNAL;
     OPENGL_ERROR_CHECK(opengl);
 
     if ((ret = opengl_prepare(opengl)) < 0)
         goto fail;
 
     opengl->glprocs.glBindBuffer(FF_GL_ARRAY_BUFFER, opengl->vertex_buffer);
     opengl->glprocs.glBindBuffer(FF_GL_ELEMENT_ARRAY_BUFFER, opengl->index_buffer);
     opengl->glprocs.glVertexAttribPointer(opengl->position_attrib, 3, GL_FLOAT, GL_FALSE, sizeof(OpenGLVertexInfo), 0);
     opengl->glprocs.glEnableVertexAttribArray(opengl->position_attrib);
     opengl->glprocs.glVertexAttribPointer(opengl->texture_coords_attrib, 2, GL_FLOAT, GL_FALSE, sizeof(OpenGLVertexInfo), 12);
     opengl->glprocs.glEnableVertexAttribArray(opengl->texture_coords_attrib);
 
     glDrawElements(GL_TRIANGLES, FF_ARRAY_ELEMS(g_index), GL_UNSIGNED_SHORT, 0);
 
     ret = AVERROR_EXTERNAL;
     OPENGL_ERROR_CHECK(opengl);
 
 #if HAVE_SDL
     if (!opengl->no_window)
         SDL_GL_SwapBuffers();
 #endif
     if (opengl->no_window &&
         (ret = avdevice_dev_to_app_control_message(h, AV_DEV_TO_APP_DISPLAY_WINDOW_BUFFER, NULL , 0)) < 0) {
         av_log(opengl, AV_LOG_ERROR, "Application failed to display window buffer.\n");
         goto fail;
     }
 
     return 0;
   fail:
     return ret;
 }
 
 static int opengl_write_packet(AVFormatContext *h, AVPacket *pkt)
 {

     return opengl_draw(h, pkt, 0, 1);
 }
 
 static int opengl_write_frame(AVFormatContext *h, int stream_index,
                               AVFrame **frame, unsigned flags)
 {
     if ((flags & AV_WRITE_UNCODED_FRAME_QUERY))
         return 0;
     return opengl_draw(h, *frame, 0, 0);

 }
 
 #define OFFSET(x) offsetof(OpenGLContext, x)
 #define ENC AV_OPT_FLAG_ENCODING_PARAM
 static const AVOption options[] = {
     { "background",   "set background color",   OFFSET(background),   AV_OPT_TYPE_COLOR,  {.str = "black"}, CHAR_MIN, CHAR_MAX, ENC },
     { "no_window",    "disable default window", OFFSET(no_window),    AV_OPT_TYPE_INT,    {.i64 = 0}, INT_MIN, INT_MAX, ENC },
     { "window_title", "set window title",       OFFSET(window_title), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, ENC },
     { NULL }
 };
 
 static const AVClass opengl_class = {
     .class_name = "opengl outdev",
     .item_name  = av_default_item_name,
     .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 
 AVOutputFormat ff_opengl_muxer = {
     .name           = "opengl",
     .long_name      = NULL_IF_CONFIG_SMALL("OpenGL output"),
     .priv_data_size = sizeof(OpenGLContext),
     .audio_codec    = AV_CODEC_ID_NONE,
     .video_codec    = AV_CODEC_ID_RAWVIDEO,
     .write_header   = opengl_write_header,
     .write_packet   = opengl_write_packet,

     .write_uncoded_frame = opengl_write_frame,

     .write_trailer  = opengl_write_trailer,
     .control_message = opengl_control_message,
     .flags          = AVFMT_NOFILE | AVFMT_VARIABLE_FPS | AVFMT_NOTIMESTAMPS,
     .priv_class     = &opengl_class,
 };