mesa: implement DrawTransformFeedback from ARB_transform_feedback2

It's like DrawArrays, but the count is taken from a transform feedback
object.

This removes DrawTransformFeedback from dd_function_table and adds the same
function to GLvertexformat (with the function parameters matching GL).

The vbo_draw_func callback has a new parameter
"struct gl_transform_feedback_object *tfb_vertcount".

The rest of the code just validates states and forwards the transform
feedback object into vbo_draw_func.

8 files changed, 112 insertions, 11 deletions

diff --git a/src/mesa/vbo/vbo.h b/src/mesa/vbo/vbo.h
index 9fbb07f3d72..f357657afa7 100644
--- a/src/mesa/vbo/vbo.h
+++ b/src/mesa/vbo/vbo.h
@@ -36,6 +36,7 @@
 
 struct gl_client_array;
 struct gl_context;
+struct gl_transform_feedback_object;
 
 struct _mesa_prim {
    GLuint mode:8;    /**< GL_POINTS, GL_LINES, GL_QUAD_STRIP, etc */
@@ -77,7 +78,8 @@ typedef void (*vbo_draw_func)( struct gl_context *ctx,
 			       const struct _mesa_index_buffer *ib,
 			       GLboolean index_bounds_valid,
 			       GLuint min_index,
-			       GLuint max_index );
+			       GLuint max_index,
+			       struct gl_transform_feedback_object *tfb_vertcount );
 
 
 
diff --git a/src/mesa/vbo/vbo_exec_array.c b/src/mesa/vbo/vbo_exec_array.c
index 97221a54d44..a6e41e9c5e5 100644
--- a/src/mesa/vbo/vbo_exec_array.c
+++ b/src/mesa/vbo/vbo_exec_array.c
@@ -34,6 +34,7 @@
 #include "main/bufferobj.h"
 #include "main/enums.h"
 #include "main/macros.h"
+#include "main/transformfeedback.h"
 
 #include "vbo_context.h"
 
@@ -608,7 +609,7 @@ vbo_draw_arrays(struct gl_context *ctx, GLenum mode, GLint start,
          /* draw one or two prims */
          check_buffers_are_unmapped(exec->array.inputs);
          vbo->draw_prims(ctx, exec->array.inputs, prim, primCount, NULL,
-                         GL_TRUE, start, start + count - 1);
+                         GL_TRUE, start, start + count - 1, NULL);
       }
    }
    else {
@@ -618,7 +619,8 @@ vbo_draw_arrays(struct gl_context *ctx, GLenum mode, GLint start,
 
       check_buffers_are_unmapped(exec->array.inputs);
       vbo->draw_prims(ctx, exec->array.inputs, prim, 1, NULL,
-                      GL_TRUE, start, start + count - 1);
+                      GL_TRUE, start, start + count - 1,
+                      NULL);
    }
 }
 
@@ -824,7 +826,7 @@ vbo_validated_drawrangeelements(struct gl_context *ctx, GLenum mode,
 
    check_buffers_are_unmapped(exec->array.inputs);
    vbo->draw_prims( ctx, exec->array.inputs, prim, 1, &ib,
-		    index_bounds_valid, start, end );
+		    index_bounds_valid, start, end, NULL );
 }
 
 
@@ -1168,7 +1170,7 @@ vbo_validated_multidrawelements(struct gl_context *ctx, GLenum mode,
 
       check_buffers_are_unmapped(exec->array.inputs);
       vbo->draw_prims(ctx, exec->array.inputs, prim, primcount, &ib,
-		      GL_FALSE, ~0, ~0);
+		      GL_FALSE, ~0, ~0, NULL);
    } else {
       /* render one prim at a time */
       for (i = 0; i < primcount; i++) {
@@ -1193,7 +1195,7 @@ vbo_validated_multidrawelements(struct gl_context *ctx, GLenum mode,
 
          check_buffers_are_unmapped(exec->array.inputs);
          vbo->draw_prims(ctx, exec->array.inputs, prim, 1, &ib,
-                         GL_FALSE, ~0, ~0);
+                         GL_FALSE, ~0, ~0, NULL);
       }
    }
 
@@ -1245,6 +1247,76 @@ vbo_exec_MultiDrawElementsBaseVertex(GLenum mode,
 				   basevertex);
 }
 
+#if FEATURE_EXT_transform_feedback
+
+static void
+vbo_draw_transform_feedback(struct gl_context *ctx, GLenum mode,
+                            struct gl_transform_feedback_object *obj,
+                            GLuint numInstances)
+{
+   struct vbo_context *vbo = vbo_context(ctx);
+   struct vbo_exec_context *exec = &vbo->exec;
+   struct _mesa_prim prim[2];
+
+   vbo_bind_arrays(ctx);
+
+   /* Again... because we may have changed the bitmask of per-vertex varying
+    * attributes.  If we regenerate the fixed-function vertex program now
+    * we may be able to prune down the number of vertex attributes which we
+    * need in the shader.
+    */
+   if (ctx->NewState)
+      _mesa_update_state(ctx);
+
+   /* init most fields to zero */
+   memset(prim, 0, sizeof(prim));
+   prim[0].begin = 1;
+   prim[0].end = 1;
+   prim[0].mode = mode;
+   prim[0].num_instances = numInstances;
+
+   /* Maybe we should do some primitive splitting for primitive restart
+    * (like in DrawArrays), but we have no way to know how many vertices
+    * will be rendered. */
+
+   check_buffers_are_unmapped(exec->array.inputs);
+   vbo->draw_prims(ctx, exec->array.inputs, prim, 1, NULL,
+                   GL_TRUE, 0, 0, obj);
+}
+
+/**
+ * Like DrawArrays, but take the count from a transform feedback object.
+ * \param mode  GL_POINTS, GL_LINES, GL_TRIANGLE_STRIP, etc.
+ * \param name  the transform feedback object
+ * User still has to setup of the vertex attribute info with
+ * glVertexPointer, glColorPointer, etc.
+ * Part of GL_ARB_transform_feedback2.
+ */
+static void GLAPIENTRY
+vbo_exec_DrawTransformFeedback(GLenum mode, GLuint name)
+{
+   GET_CURRENT_CONTEXT(ctx);
+   struct gl_transform_feedback_object *obj =
+      _mesa_lookup_transform_feedback_object(ctx, name);
+
+   if (MESA_VERBOSE & VERBOSE_DRAW)
+      _mesa_debug(ctx, "glDrawTransformFeedback(%s, %d)\n",
+                  _mesa_lookup_enum_by_nr(mode), name);
+
+   if (!_mesa_validate_DrawTransformFeedback(ctx, mode, obj)) {
+      return;
+   }
+
+   FLUSH_CURRENT(ctx, 0);
+
+   if (!_mesa_valid_to_render(ctx, "glDrawTransformFeedback")) {
+      return;
+   }
+
+   vbo_draw_transform_feedback(ctx, mode, obj, 1);
+}
+
+#endif
 
 /**
  * Plug in the immediate-mode vertex array drawing commands into the
@@ -1263,6 +1335,7 @@ vbo_exec_array_init( struct vbo_exec_context *exec )
    exec->vtxfmt.DrawArraysInstanced = vbo_exec_DrawArraysInstanced;
    exec->vtxfmt.DrawElementsInstanced = vbo_exec_DrawElementsInstanced;
    exec->vtxfmt.DrawElementsInstancedBaseVertex = vbo_exec_DrawElementsInstancedBaseVertex;
+   exec->vtxfmt.DrawTransformFeedback = vbo_exec_DrawTransformFeedback;
 }
 
 
@@ -1338,3 +1411,13 @@ _mesa_MultiDrawElementsBaseVertex(GLenum mode,
    vbo_exec_MultiDrawElementsBaseVertex(mode, count, type, indices,
 					primcount, basevertex);
 }
+
+#if FEATURE_EXT_transform_feedback
+
+void GLAPIENTRY
+_mesa_DrawTransformFeedback(GLenum mode, GLuint name)
+{
+   vbo_exec_DrawTransformFeedback(mode, name);
+}
+
+#endif
diff --git a/src/mesa/vbo/vbo_exec_draw.c b/src/mesa/vbo/vbo_exec_draw.c
index 4962b54e1f7..dd5363bebe4 100644
--- a/src/mesa/vbo/vbo_exec_draw.c
+++ b/src/mesa/vbo/vbo_exec_draw.c
@@ -411,7 +411,8 @@ vbo_exec_vtx_flush(struct vbo_exec_context *exec, GLboolean keepUnmapped)
 				       NULL,
 				       GL_TRUE,
 				       0,
-				       exec->vtx.vert_count - 1);
+				       exec->vtx.vert_count - 1,
+				       NULL);
 
 	 /* If using a real VBO, get new storage -- unless asked not to.
           */
diff --git a/src/mesa/vbo/vbo_rebase.c b/src/mesa/vbo/vbo_rebase.c
index 97c8d1297a2..597a8f46994 100644
--- a/src/mesa/vbo/vbo_rebase.c
+++ b/src/mesa/vbo/vbo_rebase.c
@@ -233,7 +233,8 @@ void vbo_rebase_prims( struct gl_context *ctx,
 	 ib, 
 	 GL_TRUE,
 	 0, 
-	 max_index - min_index );
+	 max_index - min_index,
+	 NULL );
    
    if (tmp_indices)
       free(tmp_indices);
diff --git a/src/mesa/vbo/vbo_save_api.c b/src/mesa/vbo/vbo_save_api.c
index 9d8bada04cf..9521367475e 100644
--- a/src/mesa/vbo/vbo_save_api.c
+++ b/src/mesa/vbo/vbo_save_api.c
@@ -999,6 +999,16 @@ _save_MultiDrawElementsBaseVertex(GLenum mode, const GLsizei *count,
 
 
 static void GLAPIENTRY
+_save_DrawTransformFeedback(GLenum mode, GLuint name)
+{
+   GET_CURRENT_CONTEXT(ctx);
+   (void) mode;
+   (void) name;
+   _mesa_compile_error(ctx, GL_INVALID_OPERATION, "glDrawTransformFeedback");
+}
+
+
+static void GLAPIENTRY
 _save_Rectf(GLfloat x1, GLfloat y1, GLfloat x2, GLfloat y2)
 {
    GET_CURRENT_CONTEXT(ctx);
@@ -1347,6 +1357,7 @@ _save_vtxfmt_init(struct gl_context *ctx)
    vfmt->DrawRangeElements = _save_DrawRangeElements;
    vfmt->DrawElementsBaseVertex = _save_DrawElementsBaseVertex;
    vfmt->DrawRangeElementsBaseVertex = _save_DrawRangeElementsBaseVertex;
+   vfmt->DrawTransformFeedback = _save_DrawTransformFeedback;
    vfmt->MultiDrawElementsEXT = _save_MultiDrawElements;
    vfmt->MultiDrawElementsBaseVertex = _save_MultiDrawElementsBaseVertex;
 }
diff --git a/src/mesa/vbo/vbo_save_draw.c b/src/mesa/vbo/vbo_save_draw.c
index 0773786b362..fa93ca48f43 100644
--- a/src/mesa/vbo/vbo_save_draw.c
+++ b/src/mesa/vbo/vbo_save_draw.c
@@ -299,7 +299,8 @@ vbo_save_playback_vertex_list(struct gl_context *ctx, void *data)
                                       NULL,
                                       GL_TRUE,
                                       0,    /* Node is a VBO, so this is ok */
-                                      node->count - 1);
+                                      node->count - 1,
+                                      NULL);
       }
    }
 
diff --git a/src/mesa/vbo/vbo_split_copy.c b/src/mesa/vbo/vbo_split_copy.c
index 4dcf71ef56e..b53293c3120 100644
--- a/src/mesa/vbo/vbo_split_copy.c
+++ b/src/mesa/vbo/vbo_split_copy.c
@@ -196,7 +196,8 @@ flush( struct copy_context *copy )
 	       &copy->dstib,
 	       GL_TRUE,
 	       0,
-	       copy->dstbuf_nr - 1 );
+	       copy->dstbuf_nr - 1,
+	       NULL );
 
    /* Reset all pointers: 
     */
diff --git a/src/mesa/vbo/vbo_split_inplace.c b/src/mesa/vbo/vbo_split_inplace.c
index f6aa576b6c8..9e596f66891 100644
--- a/src/mesa/vbo/vbo_split_inplace.c
+++ b/src/mesa/vbo/vbo_split_inplace.c
@@ -89,7 +89,8 @@ static void flush_vertex( struct split_context *split )
 	       split->ib ? &ib : NULL,
 	       !split->ib,
 	       split->min_index,
-	       split->max_index);
+	       split->max_index,
+	       NULL);
 
    split->dstprim_nr = 0;
    split->min_index = ~0;