From 14ae70f79328fb92886e4ebb5c950b35bcc3b5f5 Mon Sep 17 00:00:00 2001 From: Eric Anholt Date: Fri, 9 Sep 2011 14:03:41 -0700 Subject: [PATCH] i965: Set the pre/post-blend color clamp flags. No change in piglit results on gen6, but the spec demands it so let's do it. Reviewed-by: Kenneth Graunke --- src/mesa/drivers/dri/i965/gen6_cc.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/src/mesa/drivers/dri/i965/gen6_cc.c b/src/mesa/drivers/dri/i965/gen6_cc.c index b8047d5e9f0..1e6c4cfed32 100644 --- a/src/mesa/drivers/dri/i965/gen6_cc.c +++ b/src/mesa/drivers/dri/i965/gen6_cc.c @@ -99,6 +99,26 @@ prepare_blend_state(struct brw_context *brw) eqA != eqRGB); } + /* See section 8.1.6 "Pre-Blend Color Clamping" of the + * SandyBridge PRM Volume 2 Part 1 for HW requirements. + * + * We do our ARB_color_buffer_float CLAMP_FRAGMENT_COLOR + * clamping in the fragment shader. For its clamping of + * blending, the spec says: + * + * "RESOLVED: For fixed-point color buffers, the inputs and + * the result of the blending equation are clamped. For + * floating-point color buffers, no clamping occurs." + * + * So, generally, we want clamping to the render target's range. + * And, good news, the hardware tables for both pre- and + * post-blend color clamping are either ignored, or any are + * allowed, or clamping is required but RT range clamping is a + * valid option. + */ + blend[b].blend1.pre_blend_clamp_enable = 1; + blend[b].blend1.post_blend_clamp_enable = 1; + blend[b].blend1.clamp_range = BRW_RENDERTARGET_CLAMPRANGE_FORMAT; /* _NEW_COLOR */ if (ctx->Color.AlphaEnabled) { -- 2.30.2