llvmpipe: implement scissor testing

The scissor test is implemented as another per-quad operation in
the JIT code.  The four scissor box params are passed via the
lp_jit_context.  In the JIT code we compare the quad's x/y coords
against the clip bounds and create a new in/out mask that's AND'd
with the main quad mask.

Note: we should also do scissor testing in the triangle setup code
to improve efficiency.  That's not done yet.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/gallium/drivers/llvmpipe/lp_setup_context.h b/src/gallium/drivers/llvmpipe/lp_setup_context.h
index e6f6f0e0bb..fc0aef1376 100644
--- a/src/gallium/drivers/llvmpipe/lp_setup_context.h
+++ b/src/gallium/drivers/llvmpipe/lp_setup_context.h
@@ -45,6 +45,7 @@
 #define LP_SETUP_NEW_FS          0x01
 #define LP_SETUP_NEW_CONSTANTS   0x02
 #define LP_SETUP_NEW_BLEND_COLOR 0x04
+#define LP_SETUP_NEW_SCISSOR     0x08
 
 
 struct lp_scene_queue;
@@ -122,6 +123,11 @@ struct setup_context
       uint8_t *stored;
    } blend_color;
 
+   struct {
+      struct pipe_scissor_state current;
+      const void *stored;
+   } scissor;
+
    unsigned dirty;   /**< bitmask of LP_SETUP_NEW_x bits */
 
    void (*point)( struct setup_context *,