From 610910a66d1a97ca51ad8a003bdeadfe9563d721 Mon Sep 17 00:00:00 2001 From: Kenneth Graunke Date: Fri, 4 May 2012 17:06:39 -0700 Subject: [PATCH] i965: Implement guardband clipping on Ivybridge. Improves performance in Citybench: - 320x240: 9.19589% +/- 0.557621% - 1280x480: 3.90797% +/- 0.774429% No apparent difference in OpenArena. Signed-off-by: Kenneth Graunke Reviewed-by: Eric Anholt --- src/mesa/drivers/dri/i965/gen7_clip_state.c | 1 + .../drivers/dri/i965/gen7_viewport_state.c | 19 ++++++++++++++----- 2 files changed, 15 insertions(+), 5 deletions(-) diff --git a/src/mesa/drivers/dri/i965/gen7_clip_state.c b/src/mesa/drivers/dri/i965/gen7_clip_state.c index 5fede36a20d..8ff31a8b42e 100644 --- a/src/mesa/drivers/dri/i965/gen7_clip_state.c +++ b/src/mesa/drivers/dri/i965/gen7_clip_state.c @@ -101,6 +101,7 @@ upload_clip_state(struct brw_context *brw) GEN6_CLIP_MODE_NORMAL | nonperspective_barycentric_enable_flag | GEN6_CLIP_XY_TEST | + GEN6_CLIP_GB_TEST | userclip << GEN6_USER_CLIP_CLIP_DISTANCES_SHIFT | depth_clamp | provoking); diff --git a/src/mesa/drivers/dri/i965/gen7_viewport_state.c b/src/mesa/drivers/dri/i965/gen7_viewport_state.c index 2bcf338b85d..7036ef6e161 100644 --- a/src/mesa/drivers/dri/i965/gen7_viewport_state.c +++ b/src/mesa/drivers/dri/i965/gen7_viewport_state.c @@ -43,11 +43,20 @@ gen7_upload_sf_clip_viewport(struct brw_context *brw) /* Also assign to clip.vp_offset in case something uses it. */ brw->clip.vp_offset = brw->sf.vp_offset; - /* Disable guardband clipping (see gen6_viewport_state.c for rationale). */ - vp->guardband.xmin = -1.0; - vp->guardband.xmax = 1.0; - vp->guardband.ymin = -1.0; - vp->guardband.ymax = 1.0; + /* According to the "Vertex X,Y Clamping and Quantization" section of the + * Strips and Fans documentation, Ivybridge and later don't have a maximum + * post-clamp delta. However, the guardband extent must fit in [-32K, 32K) + * which gives us a maximum size of 64K. Use 65000 rather than 65536 to be + * somewhat cautious---make the guardband slightly smaller than the maximum. + */ + const float maximum_guardband_extent = 65000; + float gbx = maximum_guardband_extent / (float) ctx->Viewport.Width; + float gby = maximum_guardband_extent / (float) ctx->Viewport.Height; + + vp->guardband.xmin = -gbx; + vp->guardband.xmax = gbx; + vp->guardband.ymin = -gby; + vp->guardband.ymax = gby; /* _NEW_BUFFERS */ if (render_to_fbo) { -- 2.30.2