diff options
Diffstat (limited to 'source/blender/imbuf/intern/dds/FlipDXT.cpp')
| -rw-r--r-- | source/blender/imbuf/intern/dds/FlipDXT.cpp | 114 |
1 files changed, 57 insertions, 57 deletions
diff --git a/source/blender/imbuf/intern/dds/FlipDXT.cpp b/source/blender/imbuf/intern/dds/FlipDXT.cpp index f46f50eb2b9..9b07084bf81 100644 --- a/source/blender/imbuf/intern/dds/FlipDXT.cpp +++ b/source/blender/imbuf/intern/dds/FlipDXT.cpp @@ -31,8 +31,8 @@ * All rights reserved. */ -// This file comes from the chromium project, adapted to Blender to add DDS -// flipping to OpenGL convention for Blender +/* This file comes from the chromium project, adapted to Blender to add DDS + * flipping to OpenGL convention for Blender */ #include "IMB_imbuf_types.h" @@ -44,18 +44,18 @@ #include <FlipDXT.h> #include <Stream.h> -// A function that flips a DXTC block. +/* A function that flips a DXTC block. */ typedef void (*FlipBlockFunction)(uint8_t *block); -// Flips a full DXT1 block in the y direction. +/* Flips a full DXT1 block in the y direction. */ static void FlipDXT1BlockFull(uint8_t *block) { - // A DXT1 block layout is: - // [0-1] color0. - // [2-3] color1. - // [4-7] color bitmap, 2 bits per pixel. - // So each of the 4-7 bytes represents one line, flipping a block is just - // flipping those bytes. + /* A DXT1 block layout is: + * [0-1] color0. + * [2-3] color1. + * [4-7] color bitmap, 2 bits per pixel. + * So each of the 4-7 bytes represents one line, flipping a block is just + * flipping those bytes. */ uint8_t tmp = block[4]; block[4] = block[7]; block[7] = tmp; @@ -64,23 +64,23 @@ static void FlipDXT1BlockFull(uint8_t *block) block[6] = tmp; } -// Flips the first 2 lines of a DXT1 block in the y direction. +/* Flips the first 2 lines of a DXT1 block in the y direction. */ static void FlipDXT1BlockHalf(uint8_t *block) { - // See layout above. + /* See layout above. */ uint8_t tmp = block[4]; block[4] = block[5]; block[5] = tmp; } -// Flips a full DXT3 block in the y direction. +/* Flips a full DXT3 block in the y direction. */ static void FlipDXT3BlockFull(uint8_t *block) { - // A DXT3 block layout is: - // [0-7] alpha bitmap, 4 bits per pixel. - // [8-15] a DXT1 block. + /* A DXT3 block layout is: + * [0-7] alpha bitmap, 4 bits per pixel. + * [8-15] a DXT1 block. */ - // We can flip the alpha bits at the byte level (2 bytes per line). + /* We can flip the alpha bits at the byte level (2 bytes per line). */ uint8_t tmp = block[0]; block[0] = block[6]; @@ -95,14 +95,14 @@ static void FlipDXT3BlockFull(uint8_t *block) block[3] = block[5]; block[5] = tmp; - // And flip the DXT1 block using the above function. + /* And flip the DXT1 block using the above function. */ FlipDXT1BlockFull(block + 8); } -// Flips the first 2 lines of a DXT3 block in the y direction. +/* Flips the first 2 lines of a DXT3 block in the y direction. */ static void FlipDXT3BlockHalf(uint8_t *block) { - // See layout above. + /* See layout above. */ uint8_t tmp = block[0]; block[0] = block[2]; @@ -113,36 +113,36 @@ static void FlipDXT3BlockHalf(uint8_t *block) FlipDXT1BlockHalf(block + 8); } -// Flips a full DXT5 block in the y direction. +/* Flips a full DXT5 block in the y direction. */ static void FlipDXT5BlockFull(uint8_t *block) { - // A DXT5 block layout is: - // [0] alpha0. - // [1] alpha1. - // [2-7] alpha bitmap, 3 bits per pixel. - // [8-15] a DXT1 block. + /* A DXT5 block layout is: + * [0] alpha0. + * [1] alpha1. + * [2-7] alpha bitmap, 3 bits per pixel. + * [8-15] a DXT1 block. */ - // The alpha bitmap doesn't easily map lines to bytes, so we have to - // interpret it correctly. Extracted from - // http://www.opengl.org/registry/specs/EXT/texture_compression_s3tc.txt : - // - // The 6 "bits" bytes of the block are decoded into one 48-bit integer: - // - // bits = bits_0 + 256 * (bits_1 + 256 * (bits_2 + 256 * (bits_3 + - // 256 * (bits_4 + 256 * bits_5)))) - // - // bits is a 48-bit unsigned integer, from which a three-bit control code - // is extracted for a texel at location (x,y) in the block using: - // - // code(x,y) = bits[3*(4*y+x)+1..3*(4*y+x)+0] - // - // where bit 47 is the most significant and bit 0 is the least - // significant bit. + /* The alpha bitmap doesn't easily map lines to bytes, so we have to + * interpret it correctly. Extracted from + * http://www.opengl.org/registry/specs/EXT/texture_compression_s3tc.txt : + * + * The 6 "bits" bytes of the block are decoded into one 48-bit integer: + * + * bits = bits_0 + 256 * (bits_1 + 256 * (bits_2 + 256 * (bits_3 + + * 256 * (bits_4 + 256 * bits_5)))) + * + * bits is a 48-bit unsigned integer, from which a three-bit control code + * is extracted for a texel at location (x,y) in the block using: + * + * code(x,y) = bits[3*(4*y+x)+1..3*(4*y+x)+0] + * + * where bit 47 is the most significant and bit 0 is the least + * significant bit. */ unsigned int line_0_1 = block[2] + 256 * (block[3] + 256 * block[4]); unsigned int line_2_3 = block[5] + 256 * (block[6] + 256 * block[7]); - // swap lines 0 and 1 in line_0_1. + /* swap lines 0 and 1 in line_0_1. */ unsigned int line_1_0 = ((line_0_1 & 0x000fff) << 12) | ((line_0_1 & 0xfff000) >> 12); - // swap lines 2 and 3 in line_2_3. + /* swap lines 2 and 3 in line_2_3. */ unsigned int line_3_2 = ((line_2_3 & 0x000fff) << 12) | ((line_2_3 & 0xfff000) >> 12); block[2] = line_3_2 & 0xff; @@ -152,14 +152,14 @@ static void FlipDXT5BlockFull(uint8_t *block) block[6] = (line_1_0 & 0xff00) >> 8; block[7] = (line_1_0 & 0xff0000) >> 16; - // And flip the DXT1 block using the above function. + /* And flip the DXT1 block using the above function. */ FlipDXT1BlockFull(block + 8); } -// Flips the first 2 lines of a DXT5 block in the y direction. +/* Flips the first 2 lines of a DXT5 block in the y direction. */ static void FlipDXT5BlockHalf(uint8_t *block) { - // See layout above. + /* See layout above. */ unsigned int line_0_1 = block[2] + 256 * (block[3] + 256 * block[4]); unsigned int line_1_0 = ((line_0_1 & 0x000fff) << 12) | ((line_0_1 & 0xfff000) >> 12); block[2] = line_1_0 & 0xff; @@ -168,15 +168,15 @@ static void FlipDXT5BlockHalf(uint8_t *block) FlipDXT1BlockHalf(block + 8); } -// Flips a DXTC image, by flipping and swapping DXTC blocks as appropriate. +/* Flips a DXTC image, by flipping and swapping DXTC blocks as appropriate. */ int FlipDXTCImage( unsigned int width, unsigned int height, unsigned int levels, int fourcc, uint8_t *data) { - // must have valid dimensions + /* Must have valid dimensions. */ if (width == 0 || height == 0) { return 0; } - // height must be a power-of-two + /* Height must be a power-of-two. */ if ((height & (height - 1)) != 0) { return 0; } @@ -214,24 +214,24 @@ int FlipDXTCImage( unsigned int blocks = blocks_per_row * blocks_per_col; if (mip_height == 1) { - // no flip to do, and we're done. + /* no flip to do, and we're done. */ break; } if (mip_height == 2) { - // flip the first 2 lines in each block. + /* flip the first 2 lines in each block. */ for (unsigned int i = 0; i < blocks_per_row; i++) { half_block_function(data + i * block_bytes); } } else { - // flip each block. + /* flip each block. */ for (unsigned int i = 0; i < blocks; i++) { full_block_function(data + i * block_bytes); } - // swap each block line in the first half of the image with the - // corresponding one in the second half. - // note that this is a no-op if mip_height is 4. + /* Swap each block line in the first half of the image with the + * corresponding one in the second half. + * note that this is a no-op if mip_height is 4. */ unsigned int row_bytes = block_bytes * blocks_per_row; uint8_t *temp_line = new uint8_t[row_bytes]; @@ -247,7 +247,7 @@ int FlipDXTCImage( delete[] temp_line; } - // mip levels are contiguous. + /* mip levels are contiguous. */ data += block_bytes * blocks; mip_width = MAX(1U, mip_width >> 1); mip_height = MAX(1U, mip_height >> 1); |