2 * Copyright (C) 2011 LunarG, Inc.
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5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
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8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
11 * The above copyright notice and this permission notice (including the next
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15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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25 * \file texcompress_etc.c
26 * GL_OES_compressed_ETC1_RGB8_texture support.
30 #include "mfeatures.h"
31 #include "texcompress.h"
32 #include "texcompress_etc.h"
35 #include "swrast/s_context.h"
38 _mesa_texstore_etc1_rgb8(TEXSTORE_PARAMS
)
40 /* GL_ETC1_RGB8_OES is only valid in glCompressedTexImage2D */
46 /* define etc1_parse_block and etc. */
47 #define UINT8_TYPE GLubyte
49 #include "texcompress_etc_tmp.h"
54 _mesa_fetch_texel_2d_f_etc1_rgb8(const struct swrast_texture_image
*texImage
,
55 GLint i
, GLint j
, GLint k
, GLfloat
*texel
)
57 struct etc1_block block
;
61 src
= (const GLubyte
*) texImage
->Map
+
62 (((texImage
->RowStride
+ 3) / 4) * (j
/ 4) + (i
/ 4)) * 8;
64 etc1_parse_block(&block
, src
);
65 etc1_fetch_texel(&block
, i
% 4, j
% 4, dst
);
67 texel
[RCOMP
] = UBYTE_TO_FLOAT(dst
[0]);
68 texel
[GCOMP
] = UBYTE_TO_FLOAT(dst
[1]);
69 texel
[BCOMP
] = UBYTE_TO_FLOAT(dst
[2]);
74 * Decode texture data in format `MESA_FORMAT_ETC1_RGB8` to
75 * `MESA_FORMAT_ABGR8888`.
77 * The size of the source data must be a multiple of the ETC1 block size,
78 * which is 8, even if the texture image's dimensions are not aligned to 4.
79 * From the GL_OES_compressed_ETC1_RGB8_texture spec:
80 * The texture is described as a number of 4x4 pixel blocks. If the
81 * texture (or a particular mip-level) is smaller than 4 pixels in
82 * any dimension (such as a 2x2 or a 8x1 texture), the texture is
83 * found in the upper left part of the block(s), and the rest of the
84 * pixels are not used. For instance, a texture of size 4x2 will be
85 * placed in the upper half of a 4x4 block, and the lower half of the
86 * pixels in the block will not be accessed.
88 * \param src_width in pixels
89 * \param src_height in pixels
90 * \param dst_stride in bytes
93 _mesa_etc1_unpack_rgba8888(uint8_t *dst_row
,
95 const uint8_t *src_row
,
100 etc1_unpack_rgba8888(dst_row
, dst_stride
,
102 src_width
, src_height
);