From e0e7280db0b03b08479ef9db681db186f80605e5 Mon Sep 17 00:00:00 2001 From: Kenneth Graunke Date: Sat, 7 May 2016 17:30:02 -0700 Subject: [PATCH] i965: Clamp "Maximum VP Index" to 1 when gl_ViewportIndex isn't written. MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit fs_visitor::emit_urb_writes skips writing the VUE header for shaders that don't write gl_PointSize, gl_Layer, or gl_ViewportIndex. This leaves their values uninitialized. Kristian's nearby comment says: "But often none of the special varyings that live there are written and in that case we can skip writing to the vue header, provided the corresponding state properly clamps the values further down the pipeline." However, we were clamping gl_ViewportIndex to [0, 15], so we would end up using a random viewport. To fix this, detect when the shader doesn't write gl_ViewportIndex, and clamp it to [0, 0]. The vec4 backend always writes zeros to the VUE header, so it doesn't suffer from this problem. With vec4-style HWord writes, we can write the header and position together in a single message. In the FS world, we would need 4 extra MOVs of 0 and a longer message, or a separate OWord write. It's likely cheaper to just clamp the value. Fixes DiRT Showdown and Bioshock Infinite, which only rendered half of the screen - the lower left of two triangles. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93054 Cc: mesa-stable@lists.freedesktop.org Signed-off-by: Kenneth Graunke Reviewed-by: Kristian Høgsberg Reviewed-by: Matt Turner --- src/mesa/drivers/dri/i965/gen6_clip_state.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/src/mesa/drivers/dri/i965/gen6_clip_state.c b/src/mesa/drivers/dri/i965/gen6_clip_state.c index 5ba3a807603..8ae19c8d370 100644 --- a/src/mesa/drivers/dri/i965/gen6_clip_state.c +++ b/src/mesa/drivers/dri/i965/gen6_clip_state.c @@ -177,6 +177,11 @@ upload_clip_state(struct brw_context *brw) if (!is_drawing_points(brw) && !is_drawing_lines(brw)) dw2 |= GEN6_CLIP_XY_TEST; + /* BRW_NEW_VUE_MAP_GEOM_OUT */ + const int max_vp_index = + (brw->vue_map_geom_out.slots_valid & VARYING_BIT_VIEWPORT) != 0 ? + ctx->Const.MaxViewports : 1; + BEGIN_BATCH(4); OUT_BATCH(_3DSTATE_CLIP << 16 | (4 - 2)); OUT_BATCH(dw1); @@ -186,7 +191,7 @@ upload_clip_state(struct brw_context *brw) OUT_BATCH(U_FIXED(0.125, 3) << GEN6_CLIP_MIN_POINT_WIDTH_SHIFT | U_FIXED(255.875, 3) << GEN6_CLIP_MAX_POINT_WIDTH_SHIFT | (_mesa_geometric_layers(fb) > 0 ? 0 : GEN6_CLIP_FORCE_ZERO_RTAINDEX) | - ((ctx->Const.MaxViewports - 1) & GEN6_CLIP_MAX_VP_INDEX_MASK)); + ((max_vp_index - 1) & GEN6_CLIP_MAX_VP_INDEX_MASK)); ADVANCE_BATCH(); } @@ -201,7 +206,8 @@ const struct brw_tracked_state gen6_clip_state = { BRW_NEW_GEOMETRY_PROGRAM | BRW_NEW_META_IN_PROGRESS | BRW_NEW_PRIMITIVE | - BRW_NEW_RASTERIZER_DISCARD, + BRW_NEW_RASTERIZER_DISCARD | + BRW_NEW_VUE_MAP_GEOM_OUT, }, .emit = upload_clip_state, }; @@ -218,7 +224,8 @@ const struct brw_tracked_state gen7_clip_state = { BRW_NEW_GEOMETRY_PROGRAM | BRW_NEW_META_IN_PROGRESS | BRW_NEW_PRIMITIVE | - BRW_NEW_RASTERIZER_DISCARD, + BRW_NEW_RASTERIZER_DISCARD | + BRW_NEW_VUE_MAP_GEOM_OUT, }, .emit = upload_clip_state, }; -- 2.30.2