Mesa (master): swrast: fix readpix clamping
Marek Olšák
mareko at kemper.freedesktop.org
Fri Apr 22 04:40:10 UTC 2011
Module: Mesa
Branch: master
Commit: 1faf079a692bbf4b24c8e83fa2b331c1e3b58e13
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=1faf079a692bbf4b24c8e83fa2b331c1e3b58e13
Author: Marek Olšák <maraeo at gmail.com>
Date: Wed Apr 20 12:40:40 2011 +0200
swrast: fix readpix clamping
Broken with e5c6a92a12b5cd7db205d72039f58d302b0be9d5. (ARB_color_buffer_float)
Clamping should occur if type != float, otherwise the MSBs of the resulting
pixels are killed off. For example, reading back LUMINANCE = R+G+B can be
greater than 0xff, but the result is naturally masked by 0xff
for UNSIGNED_BYTE, leading to bogus results.
The following bug report seems to want clamping to occur if type == half_float
too. Not sure what's correct.
Bug: [bisected pineview] oglc case pxconv-read failed
https://bugs.freedesktop.org/show_bug.cgi?id=35852
Tested by: Fang Xun <xunx.fang at intel.com>
Reviewed-and-tested-by: Ian Romanick <ian.d.romanick at intel.com>
---
src/mesa/swrast/s_readpix.c | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/src/mesa/swrast/s_readpix.c b/src/mesa/swrast/s_readpix.c
index a201a63..214f2ea 100644
--- a/src/mesa/swrast/s_readpix.c
+++ b/src/mesa/swrast/s_readpix.c
@@ -318,12 +318,12 @@ read_rgba_pixels( struct gl_context *ctx,
if (!rb)
return;
- if (type == GL_FLOAT && ((ctx->Color.ClampReadColor == GL_TRUE) ||
- (ctx->Color.ClampReadColor == GL_FIXED_ONLY_ARB &&
- rb->DataType != GL_FLOAT)))
+ if ((ctx->Color._ClampReadColor == GL_TRUE || type != GL_FLOAT) &&
+ !_mesa_is_integer_format(format)) {
transferOps |= IMAGE_CLAMP_BIT;
+ }
- /* Try optimized path first */
+ /* Try the optimized path first. */
if (fast_read_rgba_pixels(ctx, x, y, width, height,
format, type, pixels, packing, transferOps)) {
return; /* done! */
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