gallium: added draw_texture_samplers() to support texture fetches from vertex shaders

This may only be practical for the softpipe driver at this time.

src/gallium/auxiliary/draw/draw_context.c

@@ -331,6 +331,21 @@ draw_num_vs_outputs(const struct draw_context *draw)
 }
 
 
+/**
+ * Provide TGSI sampler objects for vertex shaders that use texture fetches.
+ * This might only be used by software drivers for the time being.
+ */
+void
+draw_texture_samplers(struct draw_context *draw,
+                      uint num_samplers,
+                      struct tgsi_sampler **samplers)
+{
+   draw->vs.num_samplers = num_samplers;
+   draw->vs.samplers = samplers;
+}
+
+
+
 
 void draw_set_render( struct draw_context *draw, 
 		      struct vbuf_render *render )

src/gallium/auxiliary/draw/draw_context.h

@@ -45,7 +45,7 @@ struct pipe_context;
 struct draw_context;
 struct draw_stage;
 struct draw_vertex_shader;
-
+struct tgsi_sampler;
 
 
 struct draw_context *draw_create( void );
@@ -91,6 +91,12 @@ uint
 draw_num_vs_outputs(const struct draw_context *draw);
 
 
+void
+draw_texture_samplers(struct draw_context *draw,
+                      uint num_samplers,
+                      struct tgsi_sampler **samplers);
+
+
 
 /*
  * Vertex shader functions

src/gallium/auxiliary/draw/draw_private.h

@@ -185,6 +185,9 @@ struct draw_context
       /** TGSI program interpreter runtime state */
       struct tgsi_exec_machine machine;
 
+      uint num_samplers;
+      struct tgsi_sampler **samplers;
+
       /* This (and the tgsi_exec_machine struct) probably need to be moved somewhere private.
        */
       struct gallivm_cpu_engine *engine;   

src/gallium/auxiliary/draw/draw_vs_exec.c

@@ -68,8 +68,8 @@ vs_exec_prepare( struct draw_vertex_shader *shader,
    if (evs->machine->Tokens != shader->state.tokens) {
       tgsi_exec_machine_bind_shader(evs->machine,
                                     shader->state.tokens,
-                                    PIPE_MAX_SAMPLERS,
-                                    NULL /*samplers*/ );
+                                    draw->vs.num_samplers,
+                                    draw->vs.samplers);
    }
 }