Mesa (master): mesa: simplify ycbcr->rgb conversion code
Brian Paul
brianp at kemper.freedesktop.org
Thu Apr 2 02:25:44 UTC 2009
Module: Mesa
Branch: master
Commit: efe3d10aea305c89e66decfb5a9012feb7a4695c
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=efe3d10aea305c89e66decfb5a9012feb7a4695c
Author: Brian Paul <brianp at vmware.com>
Date: Mon Mar 9 20:51:21 2009 -0600
mesa: simplify ycbcr->rgb conversion code
---
src/mesa/main/texformat_tmp.h | 46 ++++++++++++----------------------------
1 files changed, 14 insertions(+), 32 deletions(-)
diff --git a/src/mesa/main/texformat_tmp.h b/src/mesa/main/texformat_tmp.h
index f98e857..d0d3804 100644
--- a/src/mesa/main/texformat_tmp.h
+++ b/src/mesa/main/texformat_tmp.h
@@ -1334,9 +1334,9 @@ static void store_texel_signed_rgba8888_rev(struct gl_texture_image *texImage,
/* MESA_FORMAT_YCBCR *********************************************************/
-/* Fetch texel from 1D, 2D or 3D ycbcr texture, return 4 GLchans */
-/* We convert YCbCr to RGB here */
-/* XXX this may break if GLchan != GLubyte */
+/* Fetch texel from 1D, 2D or 3D ycbcr texture, return 4 GLfloats.
+ * We convert YCbCr to RGB here.
+ */
static void FETCH(f_ycbcr)( const struct gl_texture_image *texImage,
GLint i, GLint j, GLint k, GLfloat *texel )
{
@@ -1346,19 +1346,10 @@ static void FETCH(f_ycbcr)( const struct gl_texture_image *texImage,
const GLubyte cb = *src0 & 0xff; /* chroma U */
const GLubyte y1 = (*src1 >> 8) & 0xff; /* luminance */
const GLubyte cr = *src1 & 0xff; /* chroma V */
- GLfloat r, g, b;
- if (i & 1) {
- /* odd pixel: use y1,cr,cb */
- r = 1.164 * (y1-16) + 1.596 * (cr-128);
- g = 1.164 * (y1-16) - 0.813 * (cr-128) - 0.391 * (cb-128);
- b = 1.164 * (y1-16) + 2.018 * (cb-128);
- }
- else {
- /* even pixel: use y0,cr,cb */
- r = 1.164 * (y0-16) + 1.596 * (cr-128);
- g = 1.164 * (y0-16) - 0.813 * (cr-128) - 0.391 * (cb-128);
- b = 1.164 * (y0-16) + 2.018 * (cb-128);
- }
+ const GLfloat y = (i & 1) ? y1 : y0; /* choose even/odd luminance */
+ GLfloat r = 1.164 * (y - 16) + 1.596 * (cr - 128);
+ GLfloat g = 1.164 * (y - 16) - 0.813 * (cr - 128) - 0.391 * (cb - 128);
+ GLfloat b = 1.164 * (y - 16) + 2.018 * (cb - 128);
r *= (1.0 / 255.0F);
g *= (1.0 / 255.0F);
b *= (1.0 / 255.0F);
@@ -1384,9 +1375,9 @@ static void store_texel_ycbcr(struct gl_texture_image *texImage,
/* MESA_FORMAT_YCBCR_REV *****************************************************/
-/* Fetch texel from 1D, 2D or 3D ycbcr_rev texture, return 4 GLchans */
-/* We convert YCbCr to RGB here */
-/* XXX this may break if GLchan != GLubyte */
+/* Fetch texel from 1D, 2D or 3D ycbcr_rev texture, return 4 GLfloats.
+ * We convert YCbCr to RGB here.
+ */
static void FETCH(f_ycbcr_rev)( const struct gl_texture_image *texImage,
GLint i, GLint j, GLint k, GLfloat *texel )
{
@@ -1396,19 +1387,10 @@ static void FETCH(f_ycbcr_rev)( const struct gl_texture_image *texImage,
const GLubyte cr = (*src0 >> 8) & 0xff; /* chroma V */
const GLubyte y1 = *src1 & 0xff; /* luminance */
const GLubyte cb = (*src1 >> 8) & 0xff; /* chroma U */
- GLfloat r, g, b;
- if (i & 1) {
- /* odd pixel: use y1,cr,cb */
- r = 1.164 * (y1-16) + 1.596 * (cr-128);
- g = 1.164 * (y1-16) - 0.813 * (cr-128) - 0.391 * (cb-128);
- b = 1.164 * (y1-16) + 2.018 * (cb-128);
- }
- else {
- /* even pixel: use y0,cr,cb */
- r = 1.164 * (y0-16) + 1.596 * (cr-128);
- g = 1.164 * (y0-16) - 0.813 * (cr-128) - 0.391 * (cb-128);
- b = 1.164 * (y0-16) + 2.018 * (cb-128);
- }
+ const GLfloat y = (i & 1) ? y1 : y0; /* choose even/odd luminance */
+ GLfloat r = 1.164 * (y - 16) + 1.596 * (cr - 128);
+ GLfloat g = 1.164 * (y - 16) - 0.813 * (cr - 128) - 0.391 * (cb - 128);
+ GLfloat b = 1.164 * (y - 16) + 2.018 * (cb - 128);
r *= (1.0 / 255.0F);
g *= (1.0 / 255.0F);
b *= (1.0 / 255.0F);
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