vbo: Avoid extra validation of DrawElements.

This saves mapping the index buffer to get a bounds on the indices that
drivers just drop on the floor in the VBO case (cache win), saves a bonus
walk of the indices in the CheckArrayBounds case, and other miscellaneous
validation.  On intel it's a particularly a large win (50-100% in my app)
because even though we let the indices stay in both CPU and GPU caches, we
still end up waiting for the GPU to be done with the buffer before reading
from it.

Drivers that want the min/max_index fields must now check index_bounds_valid
and use vbo_get_minmax_index before using them.

1 files changed, 84 insertions, 74 deletions

diff --git a/src/mesa/vbo/vbo_exec_array.c b/src/mesa/vbo/vbo_exec_array.c
index f4b9b2f7443..4fb4845f6b6 100644
--- a/src/mesa/vbo/vbo_exec_array.c
+++ b/src/mesa/vbo/vbo_exec_array.c
@@ -41,15 +41,29 @@
 /**
  * Compute min and max elements for glDraw[Range]Elements() calls.
  */
-static void
-get_minmax_index(GLuint count, GLuint type, const GLvoid *indices,
-                 GLuint *min_index, GLuint *max_index)
+void
+vbo_get_minmax_index(GLcontext *ctx,
+		     const struct _mesa_prim *prim,
+		     const struct _mesa_index_buffer *ib,
+		     GLuint *min_index, GLuint *max_index)
 {
    GLuint i;
+   GLsizei count = prim->count;
+   const void *indices;
+
+   if (ib->obj->Name) {
+      const GLvoid *map = ctx->Driver.MapBuffer(ctx,
+                                                GL_ELEMENT_ARRAY_BUFFER_ARB,
+                                                GL_READ_ONLY,
+                                                ib->obj);
+      indices = ADD_POINTERS(map, ib->ptr);
+   } else {
+      indices = ib->ptr;
+   }
 
-   switch(type) {
+   switch (ib->type) {
    case GL_UNSIGNED_INT: {
-      const GLuint *ui_indices = (const GLuint *)indices;
+      const GLuint *ui_indices = (const GLuint *)ib->ptr;
       GLuint max_ui = ui_indices[count-1];
       GLuint min_ui = ui_indices[0];
       for (i = 0; i < count; i++) {
@@ -88,6 +102,12 @@ get_minmax_index(GLuint count, GLuint type, const GLvoid *indices,
       assert(0);
       break;
    }
+
+   if (ib->obj->Name != 0) {
+      ctx->Driver.UnmapBuffer(ctx,
+			      GL_ELEMENT_ARRAY_BUFFER_ARB,
+			      ib->obj);
+   }
 }
 
 
@@ -500,7 +520,7 @@ vbo_exec_DrawArrays(GLenum mode, GLint start, GLsizei count)
    prim[0].indexed = 0;
 
    vbo->draw_prims( ctx, exec->array.inputs, prim, 1, NULL,
-                    start, start + count - 1 );
+                    GL_TRUE, start, start + count - 1 );
 
 #if 0
    print_draw_arrays(ctx, exec, mode, start, count);
@@ -566,53 +586,19 @@ dump_element_buffer(GLcontext *ctx, GLenum type)
                            ctx->Array.ElementArrayBufferObj);
 }
 
-
-static void GLAPIENTRY
-vbo_exec_DrawRangeElements(GLenum mode,
-			   GLuint start, GLuint end,
-			   GLsizei count, GLenum type, const GLvoid *indices)
+/* Inner support for both _mesa_DrawElements and _mesa_DrawRangeElements */
+static void
+vbo_validated_drawrangeelements(GLcontext *ctx, GLenum mode,
+				GLboolean index_bounds_valid,
+				GLuint start, GLuint end,
+				GLsizei count, GLenum type,
+				const GLvoid *indices)
 {
-   GET_CURRENT_CONTEXT(ctx);
    struct vbo_context *vbo = vbo_context(ctx);
    struct vbo_exec_context *exec = &vbo->exec;
    struct _mesa_index_buffer ib;
    struct _mesa_prim prim[1];
 
-   if (!_mesa_validate_DrawRangeElements( ctx, mode, start, end, count,
-                                          type, indices ))
-      return;
-
-   if (end >= ctx->Array.ArrayObj->_MaxElement) {
-      /* the max element is out of bounds of one or more enabled arrays */
-      _mesa_warning(ctx, "glDraw[Range]Elements(start %u, end %u, count %d, "
-                    "type 0x%x, indices=%p)\n"
-                    "\tindex=%u is out of bounds (max=%u)  "
-                    "Element Buffer %u (size %d)",
-                    start, end, count, type, indices, end,
-                    ctx->Array.ArrayObj->_MaxElement - 1,
-                    ctx->Array.ElementArrayBufferObj->Name,
-                    ctx->Array.ElementArrayBufferObj->Size);
-
-      if (0)
-         dump_element_buffer(ctx, type);
-
-      if (0)
-         _mesa_print_arrays(ctx);
-      return;
-   }
-   else if (0) {
-      _mesa_printf("glDraw[Range]Elements"
-                   "(start %u, end %u, type 0x%x, count %d) ElemBuf %u\n",
-                   start, end, type, count,
-                   ctx->Array.ElementArrayBufferObj->Name);
-   }
-
-#if 0
-   check_draw_elements_data(ctx, count, type, indices);
-#else
-   (void) check_draw_elements_data;
-#endif
-
    FLUSH_CURRENT( ctx, 0 );
 
    if (ctx->NewState)
@@ -623,13 +609,13 @@ vbo_exec_DrawRangeElements(GLenum mode,
       return;
    }
 
-   bind_arrays( ctx );
-
    if (ctx->NewState)
       _mesa_update_state( ctx );
 
+   bind_arrays( ctx );
+
    ib.count = count;
-   ib.type = type; 
+   ib.type = type;
    ib.obj = ctx->Array.ElementArrayBufferObj;
    ib.ptr = indices;
 
@@ -673,44 +659,68 @@ vbo_exec_DrawRangeElements(GLenum mode,
     * for the latter case elsewhere.
     */
 
-   vbo->draw_prims( ctx, exec->array.inputs, prim, 1, &ib, start, end );
+   vbo->draw_prims( ctx, exec->array.inputs, prim, 1, &ib,
+		    index_bounds_valid, start, end );
 }
 
-
 static void GLAPIENTRY
-vbo_exec_DrawElements(GLenum mode, GLsizei count, GLenum type,
-                      const GLvoid *indices)
+vbo_exec_DrawRangeElements(GLenum mode,
+			   GLuint start, GLuint end,
+			   GLsizei count, GLenum type, const GLvoid *indices)
 {
    GET_CURRENT_CONTEXT(ctx);
-   GLuint min_index = 0;
-   GLuint max_index = 0;
 
-   if (!_mesa_validate_DrawElements( ctx, mode, count, type, indices ))
+   if (!_mesa_validate_DrawRangeElements( ctx, mode, start, end, count,
+                                          type, indices ))
       return;
 
-   if (!vbo_validate_shaders(ctx)) {
-      _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawElements(bad shader)");
+   if (end >= ctx->Array.ArrayObj->_MaxElement) {
+      /* the max element is out of bounds of one or more enabled arrays */
+      _mesa_warning(ctx, "glDraw[Range]Elements(start %u, end %u, count %d, "
+                    "type 0x%x, indices=%p)\n"
+                    "\tindex=%u is out of bounds (max=%u)  "
+                    "Element Buffer %u (size %d)",
+                    start, end, count, type, indices, end,
+                    ctx->Array.ArrayObj->_MaxElement - 1,
+                    ctx->Array.ElementArrayBufferObj->Name,
+                    ctx->Array.ElementArrayBufferObj->Size);
+
+      if (0)
+         dump_element_buffer(ctx, type);
+
+      if (0)
+         _mesa_print_arrays(ctx);
       return;
    }
+   else if (0) {
+      _mesa_printf("glDraw[Range]Elements"
+                   "(start %u, end %u, type 0x%x, count %d) ElemBuf %u\n",
+                   start, end, type, count,
+                   ctx->Array.ElementArrayBufferObj->Name);
+   }
 
-   if (ctx->Array.ElementArrayBufferObj->Name) {
-      const GLvoid *map = ctx->Driver.MapBuffer(ctx,
-                                                GL_ELEMENT_ARRAY_BUFFER_ARB,
-                                                GL_READ_ONLY,
-                                                ctx->Array.ElementArrayBufferObj);
+#if 0
+   check_draw_elements_data(ctx, count, type, indices);
+#else
+   (void) check_draw_elements_data;
+#endif
+
+   vbo_validated_drawrangeelements(ctx, mode, GL_TRUE, start, end,
+				   count, type, indices);
+}
 
-      get_minmax_index(count, type, ADD_POINTERS(map, indices),
-                       &min_index, &max_index);
 
-      ctx->Driver.UnmapBuffer(ctx,
-			      GL_ELEMENT_ARRAY_BUFFER_ARB,
-			      ctx->Array.ElementArrayBufferObj);
-   }
-   else {
-      get_minmax_index(count, type, indices, &min_index, &max_index);
-   }
+static void GLAPIENTRY
+vbo_exec_DrawElements(GLenum mode, GLsizei count, GLenum type,
+                      const GLvoid *indices)
+{
+   GET_CURRENT_CONTEXT(ctx);
+
+   if (!_mesa_validate_DrawElements( ctx, mode, count, type, indices ))
+      return;
 
-   vbo_exec_DrawRangeElements(mode, min_index, max_index, count, type, indices);
+   vbo_validated_drawrangeelements(ctx, mode, GL_FALSE, ~0, ~0,
+				   count, type, indices);
 }