svga: Set alpha to 1 for non-alpha views

Gallium RGB textures may be backed by imported ARGB svga3d surfaces. In those
and similar cases we need to set the alpha value to 1 when sampling.

Fixes piglit glx::glx-tfp

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Charmaine Lee <charmainel@vmware.com>

diff --git a/src/gallium/drivers/svga/svga_shader.c b/src/gallium/drivers/svga/svga_shader.c
index 55f7922..669672d 100644 (file)
--- a/src/gallium/drivers/svga/svga_shader.c
+++ b/src/gallium/drivers/svga/svga_shader.c
@@ -25,10 +25,13 @@
 
 #include "util/u_bitmask.h"
 #include "util/u_memory.h"
+#include "util/u_format.h"
 #include "svga_context.h"
 #include "svga_cmd.h"
 #include "svga_format.h"
 #include "svga_shader.h"
+#include "svga_resource_texture.h"
+#include "svga3d_surfacedefs.h"
 
 
 /**
@@ -213,6 +216,21 @@ svga_init_shader_key_common(const struct svga_context *svga,
          key->tex[i].swizzle_g = view->swizzle_g;
          key->tex[i].swizzle_b = view->swizzle_b;
          key->tex[i].swizzle_a = view->swizzle_a;
+
+         /* If we have a non-alpha view into an svga3d surface with an
+          * alpha channel, then explicitly set the alpha channel to 1
+          * when sampling. Note that we need to check the svga3d format
+          * in the svga texture key, since the imported format is
+          * stored here and it may differ from the gallium format.
+          */
+         if (!util_format_has_alpha(view->format)) {
+            enum svga3d_block_desc block_desc =
+               svga3dsurface_get_desc(svga_texture(view->texture)->key.format)->
+               block_desc;
+
+            if (block_desc & SVGA3DBLOCKDESC_ALPHA)
+               key->tex[i].swizzle_a = PIPE_SWIZZLE_1;
+         }
       }
    }
 }