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Comment cleanup.

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extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%403309
This commit is contained in:
Ryan C. Gordon 2008-12-07 07:16:40 +00:00
parent 0096fd0e8d
commit 546fea4e11
1 changed files with 28 additions and 24 deletions
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52
src/video/SDL_renderer_gl.c
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@ -528,64 +528,68 @@ compile_shader(GL_RenderData *data, GLenum shader_type, const char *_code)
data->glBindProgramARB(shader_type, 0);
data->glDeleteProgramsARB(1, &program);
return 0;
} // if
}
return program;
}
// UYVY to RGB equasion...
// R = 1.164(Y-16) + 1.596(Cr-128)
// G = 1.164(Y-16) - 0.813(Cr-128) - 0.391(Cb-128)
// B = 1.164(Y-16) + 2.018(Cb-128)
// Byte layout is Cb, Y1, Cr, Y2.
// 4 bytes == 2 pixels: Y1/Cb/Cr, Y2/Cb/Cr
// !!! FIXME: this ignores blendmodes, etc.
// !!! FIXME: this could be more efficient...use a dot product for green, etc.
/*
* Fragment program that renders from UYVY textures.
* The UYVY to RGB equasion is:
* R = 1.164(Y-16) + 1.596(Cr-128)
* G = 1.164(Y-16) - 0.813(Cr-128) - 0.391(Cb-128)
* B = 1.164(Y-16) + 2.018(Cb-128)
* Byte layout is Cb, Y1, Cr, Y2, stored in the R, G, B, A channels.
* 4 bytes == 2 pixels: Y1/Cb/Cr, Y2/Cb/Cr
*
* !!! FIXME: this ignores blendmodes, etc.
* !!! FIXME: this could be more efficient...use a dot product for green, etc.
*/
static const char *fragment_program_UYVY_source_code =
"!!ARBfp1.0\n"
// outputs...
/* outputs... */
"OUTPUT outcolor = result.color;\n"
// scratch registers...
/* scratch registers... */
"TEMP uyvy;\n"
"TEMP luminance;\n"
"TEMP work;\n"
// We need 32 bits to store the data, but each pixel is 16 bits in itself.
// halve the coordinates to grab the correct 32 bits for the fragment.
/* Halve the coordinates to grab the correct 32 bits for the fragment. */
"MUL work, fragment.texcoord, { 0.5, 1.0, 1.0, 1.0 };\n"
// Sample the YUV texture. Cb, Y1, Cr, Y2, are stored x,y,z,w
/* Sample the YUV texture. Cb, Y1, Cr, Y2, are stored in x, y, z, w. */
"TEX uyvy, work, texture[0], %TEXTURETARGET%;\n"
// Do subtractions (128/255, 16/255, 128/255, 16/255)
/* Do subtractions (128/255, 16/255, 128/255, 16/255) */
"SUB uyvy, uyvy, { 0.501960784313726, 0.06274509803922, 0.501960784313726, 0.06274509803922 };\n"
// Choose the luminance component by texcoord.
// !!! FIXME: laziness wins out for now... just average Y1 and Y2.
/* Choose the luminance component by texcoord. */
/* !!! FIXME: laziness wins out for now... just average Y1 and Y2. */
"ADD luminance, uyvy.yyyy, uyvy.wwww;\n"
"MUL luminance, luminance, { 0.5, 0.5, 0.5, 0.5 };\n"
// Multiply luminance by its magic value.
/* Multiply luminance by its magic value. */
"MUL luminance, luminance, { 1.164, 1.164, 1.164, 1.164 };\n"
// uyvy.xyzw becomes Cr/Cr/Cb/Cb, with multiplications.
/* uyvy.xyzw becomes Cr/Cr/Cb/Cb, with multiplications. */
"MUL uyvy, uyvy.zzxx, { 1.596, -0.813, 2.018, -0.391 };\n"
// Add luminance Cr and Cb, store to RGB channels.
/* Add luminance to Cr and Cb, store to RGB channels. */
"ADD work.rgb, luminance, uyvy;\n"
// Do final addition for Green channel. (!!! FIXME: this should be a DPH?)
/* Do final addition for Green channel. (!!! FIXME: this should be a DPH?) */
"ADD work.g, work.g, uyvy.w;\n"
// Make sure alpha channel is fully opaque. (!!! FIXME: blend modes!)
/* Make sure alpha channel is fully opaque. (!!! FIXME: blend modes!) */
"MOV work.a, { 1.0 };\n"
// Store out the final fragment color.
/* Store out the final fragment color... */
"MOV outcolor, work;\n"
// ...and we're done.
/* ...and we're done! */
"END\n";