gallium: Add texture usage flags, special-case allocation of display targets

For many envirionments it's necessary to allocate display targets
in a window-system friendly manner.  Add facilities so that a driver
can tell if a texture is likely to be used to generate a display surface
and if use special allocation paths if necessary.

Hook up softpipe to call into the winsys->surface_alloc_storage()
routine in this case, though we probably want to change that interface
slightly also.

1 files changed, 5 insertions, 1 deletions

diff --git a/src/gallium/include/pipe/p_state.h b/src/gallium/include/pipe/p_state.h
index 277ee4b319..d7565dff96 100644
--- a/src/gallium/include/pipe/p_state.h
+++ b/src/gallium/include/pipe/p_state.h
@@ -284,6 +284,10 @@ struct pipe_surface
 };
 
 
+#define PIPE_TEXTURE_USAGE_RENDER_TARGET   0x1
+#define PIPE_TEXTURE_USAGE_DISPLAY_TARGET  0x2 /* ie a backbuffer */
+#define PIPE_TEXTURE_USAGE_SAMPLER         0x4
+
 /**
  * Texture object.
  */
@@ -300,7 +304,7 @@ struct pipe_texture
    unsigned last_level:8;    /**< Index of last mipmap level present/defined */
    unsigned compressed:1;
    
-   unsigned usage;
+   unsigned tex_usage;          /* PIPE_TEXTURE_USAGE_* */
 
    /* These are also refcounted:
     */