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-rw-r--r--src/mesa/drivers/dri/i965/brw_draw.c16
1 files changed, 14 insertions, 2 deletions
diff --git a/src/mesa/drivers/dri/i965/brw_draw.c b/src/mesa/drivers/dri/i965/brw_draw.c
index 7195ec89179..8c37e0b5ef8 100644
--- a/src/mesa/drivers/dri/i965/brw_draw.c
+++ b/src/mesa/drivers/dri/i965/brw_draw.c
@@ -136,6 +136,14 @@ static void gen6_set_prim(struct brw_context *brw,
}
+/**
+ * The hardware is capable of removing dangling vertices on its own; however,
+ * prior to Gen6, we sometimes convert quads into trifans (and quad strips
+ * into tristrips), since pre-Gen6 hardware requires a GS to render quads.
+ * This function manually trims dangling vertices from a draw call involving
+ * quads so that those dangling vertices won't get drawn when we convert to
+ * trifans/tristrips.
+ */
static GLuint trim(GLenum prim, GLuint length)
{
if (prim == GL_QUAD_STRIP)
@@ -171,7 +179,11 @@ static void brw_emit_prim(struct brw_context *brw,
start_vertex_location += brw->vb.start_vertex_bias;
}
- verts_per_instance = trim(prim->mode, prim->count);
+ /* We only need to trim the primitive count on pre-Gen6. */
+ if (intel->gen < 6)
+ verts_per_instance = trim(prim->mode, prim->count);
+ else
+ verts_per_instance = prim->count;
/* If nothing to emit, just return. */
if (verts_per_instance == 0)
@@ -228,7 +240,7 @@ static void gen7_emit_prim(struct brw_context *brw,
start_vertex_location += brw->vb.start_vertex_bias;
}
- verts_per_instance = trim(prim->mode, prim->count);
+ verts_per_instance = prim->count;
/* If nothing to emit, just return. */
if (verts_per_instance == 0)