vbo: Avoid unnecessary copy to/from current in vertex format upgrade.

Rebuilding the vertex format from scratch every time we see a new
vertex attribute is rather costly, new attributes can be appended at
the end avoiding a copy to current and then back again, and the full
attr pointer recalculation.

In the not so likely case of an already existing attribute having its
size increased the old behavior is preserved, this could be optimized
more, not sure if it's worth it.

It's a modest improvement in FlightGear (that game punishes the VBO
module pretty hard in general, framerate goes from some 46 FPS to 50
FPS with the nouveau classic driver).

Signed-off-by: Brian Paul <brianp@vmware.com>

1 files changed, 5 insertions, 8 deletions

diff --git a/src/mesa/vbo/vbo_exec_draw.c b/src/mesa/vbo/vbo_exec_draw.c
index 71ac0066ca..94aa021ac9 100644
--- a/src/mesa/vbo/vbo_exec_draw.c
+++ b/src/mesa/vbo/vbo_exec_draw.c
@@ -160,7 +160,6 @@ vbo_exec_bind_arrays( struct gl_context *ctx )
    struct vbo_exec_context *exec = &vbo->exec;
    struct gl_client_array *arrays = exec->vtx.arrays;
    const GLuint count = exec->vtx.vert_count;
-   const GLubyte *data = (GLubyte *) exec->vtx.buffer_map;
    const GLuint *map;
    GLuint attr;
    GLbitfield varying_inputs = 0x0;
@@ -215,6 +214,9 @@ vbo_exec_bind_arrays( struct gl_context *ctx )
       const GLuint src = map[attr];
 
       if (exec->vtx.attrsz[src]) {
+	 GLsizeiptr offset = (GLbyte *)exec->vtx.attrptr[src] -
+	    (GLbyte *)exec->vtx.vertex;
+
          /* override the default array set above */
          ASSERT(attr < Elements(exec->vtx.inputs));
          ASSERT(attr < Elements(exec->vtx.arrays)); /* arrays[] */
@@ -222,17 +224,13 @@ vbo_exec_bind_arrays( struct gl_context *ctx )
 
          if (_mesa_is_bufferobj(exec->vtx.bufferobj)) {
             /* a real buffer obj: Ptr is an offset, not a pointer*/
-            GLsizeiptr offset;
             assert(exec->vtx.bufferobj->Pointer);  /* buf should be mapped */
-            offset = (GLbyte *) data -
-	       (GLbyte *) exec->vtx.bufferobj->Pointer +
-	       exec->vtx.bufferobj->Offset;
             assert(offset >= 0);
-            arrays[attr].Ptr = (void *) offset;
+            arrays[attr].Ptr = (GLubyte *)exec->vtx.bufferobj->Offset + offset;
          }
          else {
             /* Ptr into ordinary app memory */
-            arrays[attr].Ptr = (void *) data;
+            arrays[attr].Ptr = (GLubyte *)exec->vtx.buffer_map + offset;
          }
 	 arrays[attr].Size = exec->vtx.attrsz[src];
 	 arrays[attr].StrideB = exec->vtx.vertex_size * sizeof(GLfloat);
@@ -245,7 +243,6 @@ vbo_exec_bind_arrays( struct gl_context *ctx )
                                        exec->vtx.bufferobj);
 	 arrays[attr]._MaxElement = count; /* ??? */
 
-	 data += exec->vtx.attrsz[src] * sizeof(GLfloat);
          varying_inputs |= 1 << attr;
       }
    }