minor changes, comments about multiple color buffers, MRT.

src/mesa/pipe/p_state.h

@@ -49,7 +49,7 @@
 #define PIPE_MAX_CLIP_PLANES  6
 #define PIPE_MAX_CONSTANT    32
 #define PIPE_ATTRIB_MAX      32
-
+#define PIPE_MAX_COLOR_BUFS   8
 
 
 /* fwd decl */
@@ -192,9 +192,10 @@ struct pipe_stencil_state {
 
 struct pipe_framebuffer_state
 {
-   GLuint num_cbufs;               /**< Number of color bufs to draw to */
-   struct pipe_surface *cbufs[4];  /**< OpenGL can write to as many as
-                                        4 color buffers at once */
+   /** multiple colorbuffers for multiple render targets */
+   GLuint num_cbufs;
+   struct pipe_surface *cbufs[PIPE_MAX_COLOR_BUFS];
+
    struct pipe_surface *zbuf;      /**< Z buffer */
    struct pipe_surface *sbuf;      /**< Stencil buffer */
    struct pipe_surface *abuf;      /**< Accum buffer */
@@ -221,6 +222,7 @@ struct pipe_sampler_state
 #if 0 /* need these? */
    GLint BaseLevel;     /**< min mipmap level, OpenGL 1.2 */
    GLint MaxLevel;      /**< max mipmap level, OpenGL 1.2 */
+   GLfloat border_color[4];
 #endif
    GLfloat max_anisotropy;
 };

src/mesa/pipe/softpipe/sp_quad_bufloop.c

@@ -23,9 +23,15 @@ cbuf_loop_quad(struct quad_stage *qs, struct quad_header *quad)
 
    /* make copy of original colors since they can get modified
     * by blending and masking.
+    * XXX we won't have to do this if the fragment program actually emits
+    * N separate colors and we're drawing to N color buffers (MRT).
+    * But if we emitted one color and glDrawBuffer(GL_FRONT_AND_BACK) is
+    * in effect, we need to save/restore colors like this.
     */
    memcpy(tmp, quad->outputs.color, sz);
 
+   assert(softpipe->framebuffer.num_cbufs <= PIPE_MAX_COLOR_BUFS);
+
    for (i = 0; i < softpipe->framebuffer.num_cbufs; i++) {
       /* set current cbuffer */
       softpipe->cbuf = softpipe->framebuffer.cbufs[i];
@@ -45,7 +51,8 @@ cbuf_loop_quad(struct quad_stage *qs, struct quad_header *quad)
 
 /**
  * Create the colorbuffer loop stage.
- * This is used to implement GL_FRONT_AND_BACK rendering.
+ * This is used to implement multiple render targets and GL_FRONT_AND_BACK
+ * rendering.
  */
 struct quad_stage *sp_quad_bufloop_stage( struct softpipe_context *softpipe )
 {