/*
  * Texture block decompression
  * Copyright (C) 2009 Benjamin Dobell, Glass Echidna
  * Copyright (C) 2012 Matthäus G. "Anteru" Chajdas (http://anteru.net)
  * Copyright (C) 2015 Vittorio Giovara <vittorio.giovara@gmail.com>
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  * The above copyright notice and this permission notice shall be included
  * in all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  * IN THE SOFTWARE.
  */
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "libavutil/attributes.h"
 #include "libavutil/common.h"
 #include "libavutil/intreadwrite.h"

 #include "libavutil/libm.h"

 
 #include "texturedsp.h"
 

 #define RGBA(r, g, b, a) (((uint8_t)(r) <<  0) | \
                           ((uint8_t)(g) <<  8) | \
                           ((uint8_t)(b) << 16) | \

                           ((unsigned)(uint8_t)(a) << 24))

 
 static av_always_inline void extract_color(uint32_t colors[4],
                                            uint16_t color0,
                                            uint16_t color1,
                                            int dxtn, int alpha)
 {
     int tmp;
     uint8_t r0, g0, b0, r1, g1, b1;
     uint8_t a = dxtn ? 0 : 255;
 
     tmp = (color0 >> 11) * 255 + 16;
     r0  = (uint8_t) ((tmp / 32 + tmp) / 32);
     tmp = ((color0 & 0x07E0) >> 5) * 255 + 32;
     g0  = (uint8_t) ((tmp / 64 + tmp) / 64);
     tmp = (color0 & 0x001F) * 255 + 16;
     b0  = (uint8_t) ((tmp / 32 + tmp) / 32);
 
     tmp = (color1 >> 11) * 255 + 16;
     r1  = (uint8_t) ((tmp / 32 + tmp) / 32);
     tmp = ((color1 & 0x07E0) >> 5) * 255 + 32;
     g1  = (uint8_t) ((tmp / 64 + tmp) / 64);
     tmp = (color1 & 0x001F) * 255 + 16;
     b1  = (uint8_t) ((tmp / 32 + tmp) / 32);
 
     if (dxtn || color0 > color1) {
         colors[0] = RGBA(r0, g0, b0, a);
         colors[1] = RGBA(r1, g1, b1, a);
         colors[2] = RGBA((2 * r0 + r1) / 3,
                          (2 * g0 + g1) / 3,
                          (2 * b0 + b1) / 3,
                          a);
         colors[3] = RGBA((2 * r1 + r0) / 3,
                          (2 * g1 + g0) / 3,
                          (2 * b1 + b0) / 3,
                          a);
     } else {
         colors[0] = RGBA(r0, g0, b0, a);
         colors[1] = RGBA(r1, g1, b1, a);
         colors[2] = RGBA((r0 + r1) / 2,
                          (g0 + g1) / 2,
                          (b0 + b1) / 2,
                          a);
         colors[3] = RGBA(0, 0, 0, alpha);
     }
 }
 
 static inline void dxt1_block_internal(uint8_t *dst, ptrdiff_t stride,
                                        const uint8_t *block, uint8_t alpha)
 {
     int x, y;
     uint32_t colors[4];
     uint16_t color0 = AV_RL16(block + 0);
     uint16_t color1 = AV_RL16(block + 2);
     uint32_t code   = AV_RL32(block + 4);
 
     extract_color(colors, color0, color1, 0, alpha);
 
     for (y = 0; y < 4; y++) {
         for (x = 0; x < 4; x++) {
             uint32_t pixel = colors[code & 3];
             code >>= 2;
             AV_WL32(dst + x * 4, pixel);
         }
         dst += stride;
     }
 }
 
 /**
  * Decompress one block of a DXT1 texture and store the resulting
  * RGBA pixels in 'dst'. Alpha component is fully opaque.
  *
  * @param dst    output buffer.
  * @param stride scanline in bytes.
  * @param block  block to decompress.
  * @return how much texture data has been consumed.
  */
 static int dxt1_block(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
 {
     dxt1_block_internal(dst, stride, block, 255);
 
     return 8;
 }
 
 /**
  * Decompress one block of a DXT1 with 1-bit alpha texture and store
  * the resulting RGBA pixels in 'dst'. Alpha is either fully opaque or
  * fully transparent.
  *
  * @param dst    output buffer.
  * @param stride scanline in bytes.
  * @param block  block to decompress.
  * @return how much texture data has been consumed.
  */
 static int dxt1a_block(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
 {
     dxt1_block_internal(dst, stride, block, 0);
 
     return 8;
 }
 
 static inline void dxt3_block_internal(uint8_t *dst, ptrdiff_t stride,
                                        const uint8_t *block)
 {
     int x, y;
     uint32_t colors[4];
     uint16_t color0 = AV_RL16(block +  8);
     uint16_t color1 = AV_RL16(block + 10);
     uint32_t code   = AV_RL32(block + 12);
 
     extract_color(colors, color0, color1, 1, 0);
 
     for (y = 0; y < 4; y++) {
         const uint16_t alpha_code = AV_RL16(block + 2 * y);
         uint8_t alpha_values[4];
 
         alpha_values[0] = ((alpha_code >>  0) & 0x0F) * 17;
         alpha_values[1] = ((alpha_code >>  4) & 0x0F) * 17;
         alpha_values[2] = ((alpha_code >>  8) & 0x0F) * 17;
         alpha_values[3] = ((alpha_code >> 12) & 0x0F) * 17;
 
         for (x = 0; x < 4; x++) {
             uint8_t alpha = alpha_values[x];

             uint32_t pixel = colors[code & 3] | ((unsigned)alpha << 24);

             code >>= 2;
 
             AV_WL32(dst + x * 4, pixel);
         }
         dst += stride;
     }
 }
 

 /** Convert a premultiplied alpha pixel to a straight alpha pixel. */

 static av_always_inline void premult2straight(uint8_t *src)
 {
     int r = src[0];
     int g = src[1];
     int b = src[2];
     int a = src[3]; /* unchanged */
 
     src[0] = (uint8_t) r * a / 255;
     src[1] = (uint8_t) g * a / 255;
     src[2] = (uint8_t) b * a / 255;
 }
 
 /**
  * Decompress one block of a DXT2 texture and store the resulting
  * RGBA pixels in 'dst'.
  *
  * @param dst    output buffer.
  * @param stride scanline in bytes.
  * @param block  block to decompress.
  * @return how much texture data has been consumed.
  */
 static int dxt2_block(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
 {
     int x, y;
 
     dxt3_block_internal(dst, stride, block);
 
     /* This format is DXT3, but returns premultiplied alpha. It needs to be
      * converted because it's what lavc outputs (and swscale expects). */
     for (y = 0; y < 4; y++)
         for (x = 0; x < 4; x++)
             premult2straight(dst + x * 4 + y * stride);
 
     return 16;
 }
 
 /**
  * Decompress one block of a DXT3 texture and store the resulting
  * RGBA pixels in 'dst'.
  *
  * @param dst    output buffer.
  * @param stride scanline in bytes.
  * @param block  block to decompress.
  * @return how much texture data has been consumed.
  */
 static int dxt3_block(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
 {
     dxt3_block_internal(dst, stride, block);
 
     return 16;
 }
 
 /**
  * Decompress a BC 16x3 index block stored as
  *   h g f e
  *   d c b a
  *   p o n m
  *   l k j i
  *
  * Bits packed as
  *  | h | g | f | e | d | c | b | a | // Entry
  *  |765 432 107 654 321 076 543 210| // Bit
  *  |0000000000111111111112222222222| // Byte
  *
  * into 16 8-bit indices.
  */
 static void decompress_indices(uint8_t *dst, const uint8_t *src)
 {
     int block, i;
 
     for (block = 0; block < 2; block++) {
         int tmp = AV_RL24(src);
 
         /* Unpack 8x3 bit from last 3 byte block */
         for (i = 0; i < 8; i++)
             dst[i] = (tmp >> (i * 3)) & 0x7;
 
         src += 3;
         dst += 8;
     }
 }
 
 static inline void dxt5_block_internal(uint8_t *dst, ptrdiff_t stride,
                                        const uint8_t *block)
 {
     int x, y;
     uint32_t colors[4];
     uint8_t alpha_indices[16];
     uint16_t color0 = AV_RL16(block + 8);
     uint16_t color1 = AV_RL16(block + 10);
     uint32_t code   = AV_RL32(block + 12);
     uint8_t alpha0  = *(block);
     uint8_t alpha1  = *(block + 1);
 
     decompress_indices(alpha_indices, block + 2);
 
     extract_color(colors, color0, color1, 1, 0);
 
     for (y = 0; y < 4; y++) {
         for (x = 0; x < 4; x++) {
             int alpha_code = alpha_indices[x + y * 4];
             uint32_t pixel;
             uint8_t alpha;
 
             if (alpha_code == 0) {
                 alpha = alpha0;
             } else if (alpha_code == 1) {
                 alpha = alpha1;
             } else {
                 if (alpha0 > alpha1) {
                     alpha = (uint8_t) (((8 - alpha_code) * alpha0 +
                                         (alpha_code - 1) * alpha1) / 7);
                 } else {
                     if (alpha_code == 6) {
                         alpha = 0;
                     } else if (alpha_code == 7) {
                         alpha = 255;
                     } else {
                         alpha = (uint8_t) (((6 - alpha_code) * alpha0 +
                                             (alpha_code - 1) * alpha1) / 5);
                     }
                 }
             }

             pixel = colors[code & 3] | ((unsigned)alpha << 24);

             code >>= 2;
             AV_WL32(dst + x * 4, pixel);
         }
         dst += stride;
     }
 }
 
 /**
  * Decompress one block of a DXT4 texture and store the resulting
  * RGBA pixels in 'dst'.
  *
  * @param dst    output buffer.
  * @param stride scanline in bytes.
  * @param block  block to decompress.
  * @return how much texture data has been consumed.
  */
 static int dxt4_block(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
 {
     int x, y;
 
     dxt5_block_internal(dst, stride, block);
 
     /* This format is DXT5, but returns premultiplied alpha. It needs to be
      * converted because it's what lavc outputs (and swscale expects). */
     for (y = 0; y < 4; y++)
         for (x = 0; x < 4; x++)
             premult2straight(dst + x * 4 + y * stride);
 
     return 16;
 }
 
 /**
  * Decompress one block of a DXT5 texture and store the resulting
  * RGBA pixels in 'dst'.
  *
  * @param dst    output buffer.
  * @param stride scanline in bytes.
  * @param block  block to decompress.
  * @return how much texture data has been consumed.
  */
 static int dxt5_block(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
 {
     dxt5_block_internal(dst, stride, block);
 
     return 16;
 }
 
 /**
  * Convert a YCoCg buffer to RGBA.
  *
  * @param src    input buffer.
  * @param scaled variant with scaled chroma components and opaque alpha.
  */
 static av_always_inline void ycocg2rgba(uint8_t *src, int scaled)
 {
     int r = src[0];
     int g = src[1];
     int b = src[2];
     int a = src[3];
 
     int s  = scaled ? (b >> 3) + 1 : 1;
     int y  = a;
     int co = (r - 128) / s;
     int cg = (g - 128) / s;
 
     src[0] = av_clip_uint8(y + co - cg);
     src[1] = av_clip_uint8(y + cg);
     src[2] = av_clip_uint8(y - co - cg);
     src[3] = scaled ? 255 : b;
 }
 
 /**
  * Decompress one block of a DXT5 texture with classic YCoCg and store
  * the resulting RGBA pixels in 'dst'. Alpha component is fully opaque.
  *
  * @param dst    output buffer.
  * @param stride scanline in bytes.
  * @param block  block to decompress.
  * @return how much texture data has been consumed.
  */
 static int dxt5y_block(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
 {
     int x, y;
 
     /* This format is basically DXT5, with luma stored in alpha.
      * Run a normal decompress and then reorder the components. */
     dxt5_block_internal(dst, stride, block);
 
     for (y = 0; y < 4; y++)
         for (x = 0; x < 4; x++)
             ycocg2rgba(dst + x * 4 + y * stride, 0);
 
     return 16;
 }
 
 /**
  * Decompress one block of a DXT5 texture with scaled YCoCg and store
  * the resulting RGBA pixels in 'dst'. Alpha component is fully opaque.
  *
  * @param dst    output buffer.
  * @param stride scanline in bytes.
  * @param block  block to decompress.
  * @return how much texture data has been consumed.
  */
 static int dxt5ys_block(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
 {
     int x, y;
 
     /* This format is basically DXT5, with luma stored in alpha.
      * Run a normal decompress and then reorder the components. */
     dxt5_block_internal(dst, stride, block);
 
     for (y = 0; y < 4; y++)
         for (x = 0; x < 4; x++)
             ycocg2rgba(dst + x * 4 + y * stride, 1);
 
     return 16;
 }
 
 static inline void rgtc_block_internal(uint8_t *dst, ptrdiff_t stride,
                                        const uint8_t *block,

                                        const int *color_tab, int mono, int offset, int pix_size)

 {
     uint8_t indices[16];
     int x, y;
 
     decompress_indices(indices, block + 2);
 
     /* Only one or two channels are stored at most, since it only used to
      * compress specular (black and white) or normal (red and green) maps.
      * Although the standard says to zero out unused components, many
      * implementations fill all of them with the same value. */
     for (y = 0; y < 4; y++) {
         for (x = 0; x < 4; x++) {
             int i = indices[x + y * 4];
             /* Interval expansion from [-1 1] or [0 1] to [0 255]. */
             int c = color_tab[i];

             if (mono){
                 dst [x * pix_size + y * stride + offset] = (uint8_t)c;

             }
             else{
                 uint32_t pixel = RGBA(c, c, c, 255U);

                 AV_WL32(dst + x * pix_size + y * stride, pixel);

             }

         }
     }
 }
 
 static inline void rgtc1_block_internal(uint8_t *dst, ptrdiff_t stride,

                                         const uint8_t *block, int sign, int mono, int offset, int pix_size)

 {
     int color_table[8];
     int r0, r1;
 
     if (sign) {
         /* signed data is in [-128 127] so just offset it to unsigned
          * and it can be treated exactly the same */
         r0 = ((int8_t) block[0]) + 128;
         r1 = ((int8_t) block[1]) + 128;
     } else {
         r0 = block[0];
         r1 = block[1];
     }
 
     color_table[0] = r0;
     color_table[1] = r1;
 
     if (r0 > r1) {
         /* 6 interpolated color values */
         color_table[2] = (6 * r0 + 1 * r1) / 7; // bit code 010
         color_table[3] = (5 * r0 + 2 * r1) / 7; // bit code 011
         color_table[4] = (4 * r0 + 3 * r1) / 7; // bit code 100
         color_table[5] = (3 * r0 + 4 * r1) / 7; // bit code 101
         color_table[6] = (2 * r0 + 5 * r1) / 7; // bit code 110
         color_table[7] = (1 * r0 + 6 * r1) / 7; // bit code 111
     } else {
         /* 4 interpolated color values */
         color_table[2] = (4 * r0 + 1 * r1) / 5; // bit code 010
         color_table[3] = (3 * r0 + 2 * r1) / 5; // bit code 011
         color_table[4] = (2 * r0 + 3 * r1) / 5; // bit code 100
         color_table[5] = (1 * r0 + 4 * r1) / 5; // bit code 101
         color_table[6] = 0;    /* min range */  // bit code 110
         color_table[7] = 255;  /* max range */  // bit code 111
     }
 

     rgtc_block_internal(dst, stride, block, color_table, mono, offset, pix_size);

 }
 
 /**
  * Decompress one block of a RGRC1 texture with signed components
  * and store the resulting RGBA pixels in 'dst'.
  *
  * @param dst    output buffer.
  * @param stride scanline in bytes.
  * @param block  block to decompress.
  * @return how much texture data has been consumed.
  */
 static int rgtc1s_block(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
 {

     rgtc1_block_internal(dst, stride, block, 1, 0, 0, 4);

 
     return 8;
 }
 
 /**
  * Decompress one block of a RGRC1 texture with unsigned components
  * and store the resulting RGBA pixels in 'dst'.
  *
  * @param dst    output buffer.
  * @param stride scanline in bytes.
  * @param block  block to decompress.
  * @return how much texture data has been consumed.
  */
 static int rgtc1u_block(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
 {

     rgtc1_block_internal(dst, stride, block, 0, 0, 0, 4);

 
     return 8;
 }
 
 /**

  * Decompress one block of a RGTC1 texture with unsigned components

  * and overwrite the alpha component in 'dst' (RGBA data).
  *
  * @param dst    output buffer.
  * @param stride scanline in bytes.
  * @param block  block to decompress.
  * @return how much texture data has been consumed.
  */
 static int rgtc1u_alpha_block(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
 {

     rgtc1_block_internal(dst, stride, block, 0, 1, 3, 4);
 
     return 8;
 }
 
 /**
  * Decompress one block of a RGTC1 texture with unsigned components
  * to Gray 8.
  *
  * @param dst    output buffer.
  * @param stride scanline in bytes.
  * @param block  block to decompress.
  * @return how much texture data has been consumed.
  */
 static int rgtc1u_gray_block(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
 {
     rgtc1_block_internal(dst, stride, block, 0, 1, 0, 1);

 
     return 8;
 }
 
 static inline void rgtc2_block_internal(uint8_t *dst, ptrdiff_t stride,
                                         const uint8_t *block, int sign)
 {
     /* 4x4 block containing 4 component pixels. */
     uint8_t c0[4 * 4 * 4];
     uint8_t c1[4 * 4 * 4];
     int x, y;
 
     /* Decompress the two channels separately and interleave them afterwards. */

     rgtc1_block_internal(c0, 16, block, sign, 0, 0, 4);
     rgtc1_block_internal(c1, 16, block + 8, sign, 0, 0, 4);

 
     /* B is rebuilt exactly like a normal map. */
     for (y = 0; y < 4; y++) {
         for (x = 0; x < 4; x++) {
             uint8_t *p = dst + x * 4 + y * stride;
             int r = c0[x * 4 + y * 16];
             int g = c1[x * 4 + y * 16];
             int b = 127;
 
             int d = (255 * 255 - r * r - g * g) / 2;
             if (d > 0)

                 b = lrint(sqrtf(d));

 
             p[0] = r;
             p[1] = g;
             p[2] = b;
             p[3] = 255;
         }
     }
 }
 
 /**
  * Decompress one block of a RGRC2 texture with signed components
  * and store the resulting RGBA pixels in 'dst'. Alpha is fully opaque.
  *
  * @param dst    output buffer.
  * @param stride scanline in bytes.
  * @param block  block to decompress.
  * @return how much texture data has been consumed.
  */
 static int rgtc2s_block(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
 {
     rgtc2_block_internal(dst, stride, block, 1);
 
     return 16;
 }
 
 /**
  * Decompress one block of a RGRC2 texture with unsigned components
  * and store the resulting RGBA pixels in 'dst'. Alpha is fully opaque.
  *
  * @param dst    output buffer.
  * @param stride scanline in bytes.
  * @param block  block to decompress.
  * @return how much texture data has been consumed.
  */
 static int rgtc2u_block(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
 {
     rgtc2_block_internal(dst, stride, block, 0);
 
     return 16;
 }
 
 /**
  * Decompress one block of a 3Dc texture with unsigned components
  * and store the resulting RGBA pixels in 'dst'. Alpha is fully opaque.
  *
  * @param dst    output buffer.
  * @param stride scanline in bytes.
  * @param block  block to decompress.
  * @return how much texture data has been consumed.
  */
 static int dxn3dc_block(uint8_t *dst, ptrdiff_t stride, const uint8_t *block)
 {
     int x, y;
     rgtc2_block_internal(dst, stride, block, 0);
 
     /* This is the 3Dc variant of RGTC2, with swapped R and G. */
     for (y = 0; y < 4; y++) {
         for (x = 0; x < 4; x++) {
             uint8_t *p = dst + x * 4 + y * stride;
             FFSWAP(uint8_t, p[0], p[1]);
         }
     }
 
     return 16;
 }
 
 av_cold void ff_texturedsp_init(TextureDSPContext *c)
 {

     c->dxt1_block         = dxt1_block;
     c->dxt1a_block        = dxt1a_block;
     c->dxt2_block         = dxt2_block;
     c->dxt3_block         = dxt3_block;
     c->dxt4_block         = dxt4_block;
     c->dxt5_block         = dxt5_block;
     c->dxt5y_block        = dxt5y_block;
     c->dxt5ys_block       = dxt5ys_block;
     c->rgtc1s_block       = rgtc1s_block;
     c->rgtc1u_block       = rgtc1u_block;

     c->rgtc1u_gray_block  = rgtc1u_gray_block;

     c->rgtc1u_alpha_block = rgtc1u_alpha_block;

     c->rgtc2s_block       = rgtc2s_block;
     c->rgtc2u_block       = rgtc2u_block;
     c->dxn3dc_block       = dxn3dc_block;

 }