svga: disable rasterization if rasterizer_discard is set or FS undefined

With this patch, rasterization will be disabled if the
rasterizer_discard flag is set or the fragment shader
is undefined due to missing position output from the
vertex/geometry shader.

Tested with piglit test glsl-1.50-geometry-primitive-id-restart.
Also tested with full MTT glretrace and piglit.

v2: As suggested by Roland, to properly disable rasterization, besides
    setting FS to NULL, we will also need to disable depth and stencil test.

v3: As suggested by Brian, set SVGA_NEW_DEPTH_STENCIL_ALPHA dirty bit
    in svga_bind_rasterizer_state() if the rasterizer_discard flag is
    changed.

Reviewed-by: Brian Paul <[email protected]>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/gallium/drivers/svga/svga_context.h b/src/gallium/drivers/svga/svga_context.h
index 40966e9b52e..2b95a787870 100644
--- a/src/gallium/drivers/svga/svga_context.h
+++ b/src/gallium/drivers/svga/svga_context.h
@@ -399,6 +399,8 @@ struct svga_hw_draw_state
 
    /* used for rebinding */
    unsigned default_constbuf_size[PIPE_SHADER_TYPES];
+
+   boolean rasterizer_discard; /* set if rasterization is disabled */
 };
 
 
@@ -583,6 +585,9 @@ struct svga_context
    /** Alternate rasterizer states created for point sprite */
    struct svga_rasterizer_state *rasterizer_no_cull[2];
 
+   /** Depth stencil state created to disable depth stencil test */
+   struct svga_depth_stencil_state *depthstencil_disable;
+
    /** Current conditional rendering predicate */
    struct {
       SVGA3dQueryId query_id;
@@ -590,6 +595,7 @@ struct svga_context
    } pred;
 
    boolean render_condition;
+   boolean disable_rasterizer; /* Set if to disable rasterization */
 };
 
 /* A flag for each state_tracker state object: