[Mesa-dev] [PATCH] i965: Drop index buffer re-alignment code.

[Kenneth Graunke]

This shouldn't ever happen - GL requires it to be aligned:

   "Clients must align data elements consistent with the requirements
    of the client platform, with an additional base-level requirement
    that an offset within a buffer to a datum comprising N basic
    machine units be a multiple of N."

Mesa should reject unaligned index buffers for us - we shouldn't have
to handle them in the driver.

Note that Gallium already makes this assumption.
---
 src/mesa/drivers/dri/i965/brw_draw_upload.c | 38 ++++++-----------------------
 1 file changed, 8 insertions(+), 30 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_draw_upload.c b/src/mesa/drivers/dri/i965/brw_draw_upload.c
index 05b6b1a50f1..baa1de353b4 100644
--- a/src/mesa/drivers/dri/i965/brw_draw_upload.c
+++ b/src/mesa/drivers/dri/i965/brw_draw_upload.c
@@ -711,7 +711,6 @@ brw_prepare_shader_draw_parameters(struct brw_context *brw)
 static void
 brw_upload_indices(struct brw_context *brw)
 {
-   struct gl_context *ctx = &brw->ctx;
    const struct _mesa_index_buffer *index_buffer = brw->ib.ib;
    GLuint ib_size;
    struct brw_bo *old_bo = brw->ib.bo;
@@ -738,35 +737,14 @@ brw_upload_indices(struct brw_context *brw)
    } else {
       offset = (GLuint) (unsigned long) index_buffer->ptr;
 
-      /* If the index buffer isn't aligned to its element size, we have to
-       * rebase it into a temporary.
-       */
-      if ((ib_type_size - 1) & offset) {
-         perf_debug("copying index buffer to a temporary to work around "
-                    "misaligned offset %d\n", offset);
-
-         GLubyte *map = ctx->Driver.MapBufferRange(ctx,
-                                                   offset,
-                                                   ib_size,
-                                                   GL_MAP_READ_BIT,
-                                                   bufferobj,
-                                                   MAP_INTERNAL);
-
-         intel_upload_data(brw, map, ib_size, ib_type_size,
-                           &brw->ib.bo, &offset);
-         brw->ib.size = brw->ib.bo->size;
-
-         ctx->Driver.UnmapBuffer(ctx, bufferobj, MAP_INTERNAL);
-      } else {
-         struct brw_bo *bo =
-            intel_bufferobj_buffer(brw, intel_buffer_object(bufferobj),
-                                   offset, ib_size);
-         if (bo != brw->ib.bo) {
-            brw_bo_unreference(brw->ib.bo);
-            brw->ib.bo = bo;
-            brw->ib.size = bufferobj->Size;
-            brw_bo_reference(bo);
-         }
+      struct brw_bo *bo =
+         intel_bufferobj_buffer(brw, intel_buffer_object(bufferobj),
+                                offset, ib_size);
+      if (bo != brw->ib.bo) {
+         brw_bo_unreference(brw->ib.bo);
+         brw->ib.bo = bo;
+         brw->ib.size = bufferobj->Size;
+         brw_bo_reference(bo);
       }
    }
 
-- 
2.13.1