Mesa (master): anv: Fix near plane clipping on Gen7/7.5.
Kenneth Graunke
kwg at kemper.freedesktop.org
Wed Jul 20 17:59:56 UTC 2016
Module: Mesa
Branch: master
Commit: 0d77f08042b00cff81bebceb7877bc20f80c0965
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=0d77f08042b00cff81bebceb7877bc20f80c0965
Author: Kenneth Graunke <kenneth at whitecape.org>
Date: Mon Jul 18 14:15:49 2016 -0700
anv: Fix near plane clipping on Gen7/7.5.
The Gen7/7.5 clip code used APIMODE_OGL, while the Gen8+ clip code used
APIMODE_D3D. The meaning hasn't changed, so one of these must be wrong.
It appears that the hardware documentation is completely wrong. It
claims that the "API Mode" bit means:
0h APIMODE_OGL NEAR_VP boundary == 0.0 (NDC)
1h APIMODE_D3D NEAR_VP boundary == -1.0 (NDC)
However, DirectX typically uses 0.0 for the near plane, while unextended
OpenGL uses -1.0. i965's gen6_clip_state.c uses APIMODE_D3D for the
GL_ZERO_TO_ONE case, so I believe the meanings are backwards from what
the documentation says.
Section 23.2 ("Primitive Clipping") of the Vulkan 1.0.21 specification
contains the following equations:
-w_c <= x_c <= w_c
-w_c <= y_c <= w_c
0 <= z_c <= w_c
This means that Vulkan follows D3D semantics.
Cc: "12.0" <mesa-stable at lists.freedesktop.org>
Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>
---
src/intel/vulkan/gen7_pipeline.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/intel/vulkan/gen7_pipeline.c b/src/intel/vulkan/gen7_pipeline.c
index 01c04f3..a50d9c7 100644
--- a/src/intel/vulkan/gen7_pipeline.c
+++ b/src/intel/vulkan/gen7_pipeline.c
@@ -124,7 +124,7 @@ genX(graphics_pipeline_create)(
clip.FrontWinding = vk_to_gen_front_face[rs_info->frontFace],
clip.CullMode = vk_to_gen_cullmode[rs_info->cullMode],
clip.ClipEnable = !(extra && extra->use_rectlist),
- clip.APIMode = APIMODE_OGL,
+ clip.APIMode = APIMODE_D3D,
clip.ViewportXYClipTestEnable = true,
clip.ViewportZClipTestEnable = !pipeline->depth_clamp_enable,
clip.ClipMode = CLIPMODE_NORMAL,
More information about the mesa-commit
mailing list