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.

1 files changed, 88 insertions, 5 deletions

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