Mesa (master): i915g: fix incorrect gl_FragCoord value
Stephane Marchesin
marcheu at kemper.freedesktop.org
Tue Oct 11 01:33:29 UTC 2016
Module: Mesa
Branch: master
Commit: 64435fd888ec5932024292d87b0afcecbe5fb818
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=64435fd888ec5932024292d87b0afcecbe5fb818
Author: Nicholas Bishop <nicholasbishop at gmail.com>
Date: Thu Aug 25 19:31:53 2016 -0400
i915g: fix incorrect gl_FragCoord value
On Intel Pineview M hardware, the i915 gallium driver doesn't output
the correct gl_FragCoord. It seems to always have an X coord of 0.0
and a Y coord of the window's height in pixels, e.g. 600.0f or such.
I believe this is a regression caused in part by this commit:
afa035031ff9e0c07a2297d864e46c76f7bfff58
The old behavior used the output at index zero, while the new behavior
uses actual zeroes. In the case of gl_FragCoord the output at index
zero happened to be the correct one, so the behavior appeared correct
although the code already had a bug.
Fixed by checking for I915_SEMANTIC_POS when setting up texCoords. If
the generic_mapping is I915_SEMANTIC_POS, look for the
TGSI_SEMANTIC_POSITION instead of a TGSI_SEMANTIC_GENERIC output.
https://bugs.freedesktop.org/show_bug.cgi?id=97477
Reviewed-by: Stéphane Marchesin <marcheu at chromium.org>
Tested-by: Stéphane Marchesin <marcheu at chromium.org>
---
src/gallium/drivers/i915/i915_state_derived.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/src/gallium/drivers/i915/i915_state_derived.c b/src/gallium/drivers/i915/i915_state_derived.c
index 177b854..dbfbc84 100644
--- a/src/gallium/drivers/i915/i915_state_derived.c
+++ b/src/gallium/drivers/i915/i915_state_derived.c
@@ -145,7 +145,12 @@ static void calculate_vertex_layout(struct i915_context *i915)
uint hwtc;
if (texCoords[i]) {
hwtc = TEXCOORDFMT_4D;
- src = draw_find_shader_output(i915->draw, TGSI_SEMANTIC_GENERIC, fs->generic_mapping[i]);
+ if (fs->generic_mapping[i] == I915_SEMANTIC_POS) {
+ src = draw_find_shader_output(i915->draw, TGSI_SEMANTIC_POSITION, 0);
+ }
+ else {
+ src = draw_find_shader_output(i915->draw, TGSI_SEMANTIC_GENERIC, fs->generic_mapping[i]);
+ }
draw_emit_vertex_attr(&vinfo, EMIT_4F, src);
}
else {
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