[Mesa-dev] [PATCH 1/2] i965: Disable point coords when not rendering points.

[Paul Berry]

>From the Ivy Bridge PRM, p268 (3DSTATE_SBE), in the description of
"Point Sprite Texture Coordinate Enable":

    "This field must be programmed to 0 when non-point primitives are
    rendered."

A similar admonishment exists in the Sandy Bridge PRM.

Although I'm not aware of any known bugs due to us ignoring this,
defying the hardware docs is generally unwise.
---
 src/mesa/drivers/dri/i965/gen6_sf_state.c | 9 ++++++---
 src/mesa/drivers/dri/i965/gen7_sf_state.c | 9 ++++++---
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/gen6_sf_state.c b/src/mesa/drivers/dri/i965/gen6_sf_state.c
index 7071acc..d88c49a 100644
--- a/src/mesa/drivers/dri/i965/gen6_sf_state.c
+++ b/src/mesa/drivers/dri/i965/gen6_sf_state.c
@@ -127,6 +127,8 @@ upload_sf_state(struct brw_context *brw)
    /* _NEW_BUFFER */
    bool render_to_fbo = _mesa_is_user_fbo(brw->intel.ctx.DrawBuffer);
    bool multisampled_fbo = ctx->DrawBuffer->Visual.samples > 1;
+   /* BRW_NEW_REDUCED_PRIMITIVE */
+   bool is_point_primitive = intel->reduced_primitive == GL_POINTS;
 
    int attr = 0, input_index = 0;
    int urb_entry_read_offset = 1;
@@ -280,13 +282,13 @@ upload_sf_state(struct brw_context *brw)
 	 continue;
 
       /* _NEW_POINT */
-      if (ctx->Point.PointSprite &&
+      if (is_point_primitive && ctx->Point.PointSprite &&
 	  (attr >= FRAG_ATTRIB_TEX0 && attr <= FRAG_ATTRIB_TEX7) &&
 	  ctx->Point.CoordReplace[attr - FRAG_ATTRIB_TEX0]) {
 	 dw16 |= (1 << input_index);
       }
 
-      if (attr == FRAG_ATTRIB_PNTC)
+      if (is_point_primitive && attr == FRAG_ATTRIB_PNTC)
 	 dw16 |= (1 << input_index);
 
       /* flat shading */
@@ -360,7 +362,8 @@ const struct brw_tracked_state gen6_sf_state = {
 		_NEW_POINT |
                 _NEW_MULTISAMPLE),
       .brw   = (BRW_NEW_CONTEXT |
-		BRW_NEW_FRAGMENT_PROGRAM),
+		BRW_NEW_FRAGMENT_PROGRAM |
+                BRW_NEW_REDUCED_PRIMITIVE),
       .cache = CACHE_NEW_VS_PROG
    },
    .emit = upload_sf_state,
diff --git a/src/mesa/drivers/dri/i965/gen7_sf_state.c b/src/mesa/drivers/dri/i965/gen7_sf_state.c
index 9171eff..0f6252b 100644
--- a/src/mesa/drivers/dri/i965/gen7_sf_state.c
+++ b/src/mesa/drivers/dri/i965/gen7_sf_state.c
@@ -46,6 +46,8 @@ upload_sbe_state(struct brw_context *brw)
    /* _NEW_BUFFERS */
    bool render_to_fbo = _mesa_is_user_fbo(ctx->DrawBuffer);
    uint32_t point_sprite_origin;
+   /* BRW_NEW_REDUCED_PRIMITIVE */
+   bool is_point_primitive = intel->reduced_primitive == GL_POINTS;
 
    /* FINISHME: Attribute Swizzle Control Mode? */
    dw1 = GEN7_SBE_SWIZZLE_ENABLE | num_outputs << GEN7_SBE_NUM_OUTPUTS_SHIFT;
@@ -78,13 +80,13 @@ upload_sbe_state(struct brw_context *brw)
       if (!(brw->fragment_program->Base.InputsRead & BITFIELD64_BIT(attr)))
 	 continue;
 
-      if (ctx->Point.PointSprite &&
+      if (is_point_primitive && ctx->Point.PointSprite &&
 	  attr >= FRAG_ATTRIB_TEX0 && attr <= FRAG_ATTRIB_TEX7 &&
 	  ctx->Point.CoordReplace[attr - FRAG_ATTRIB_TEX0]) {
 	 dw10 |= (1 << input_index);
       }
 
-      if (attr == FRAG_ATTRIB_PNTC)
+      if (is_point_primitive && attr == FRAG_ATTRIB_PNTC)
 	 dw10 |= (1 << input_index);
 
       /* flat shading */
@@ -149,7 +151,8 @@ const struct brw_tracked_state gen7_sbe_state = {
 		_NEW_POINT |
 		_NEW_PROGRAM),
       .brw   = (BRW_NEW_CONTEXT |
-		BRW_NEW_FRAGMENT_PROGRAM),
+		BRW_NEW_FRAGMENT_PROGRAM |
+                BRW_NEW_REDUCED_PRIMITIVE),
       .cache = CACHE_NEW_VS_PROG
    },
    .emit = upload_sbe_state,
-- 
1.8.1.3