[Mesa-dev] [PATCH 5/9] i965: Relax the alignment requirements on uniform buffer objects.

[Eric Anholt]

I noticed this while looking for a cite for the similar requirement I was
going to put on texture buffer objects.

We don't actually have a test for this, but the
GL_ARB_texture_buffer_range alignment test we have makes me reasonably
confident that this works, too.

This causes a regression to be reported in gles3conform, but it's a
testcase bug that I've reported upstream.
---
 src/mesa/drivers/dri/i965/brw_context.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/mesa/drivers/dri/i965/brw_context.c b/src/mesa/drivers/dri/i965/brw_context.c
index 776d221..dee8032 100644
--- a/src/mesa/drivers/dri/i965/brw_context.c
+++ b/src/mesa/drivers/dri/i965/brw_context.c
@@ -240,7 +240,15 @@ brw_initialize_context_constants(struct brw_context *brw)
 
    ctx->Const.NativeIntegers = true;
    ctx->Const.UniformBooleanTrue = 1;
-   ctx->Const.UniformBufferOffsetAlignment = 16;
+
+   /* From the gen4 PRM, volume 4 page 127:
+    *
+    *     "For SURFTYPE_BUFFER non-rendertarget surfaces, this field specifies
+    *      the base address of the first element of the surface, computed in
+    *      software by adding the surface base address to the byte offset of
+    *      the element in the buffer."
+    */
+   ctx->Const.UniformBufferOffsetAlignment = 1;
 
    ctx->Const.ForceGLSLExtensionsWarn =
       driQueryOptionb(&brw->optionCache, "force_glsl_extensions_warn");
-- 
1.8.4.rc3