[Mesa-dev] [PATCH v3 03/16] i965/draw: Stop relying on min_index == -1 for invalid index bounds

[Jason Ekstrand]

The vbo layer passes an index_bounds_valid flag that we should be using
instead.  This also fixes a bug when min_index == -1 and basevertex != 0
where we were actually comparing min_index + basevertex == -1 which was
false and we were getting the wrong buffer-sizing path.

Cc: "11.1 11.2" <mesa-stable at lists.freedesktop.org>
Reviewed-by: Iago Toral Quiroga <itoral at igalia.com>
---
 src/mesa/drivers/dri/i965/brw_context.h     | 1 +
 src/mesa/drivers/dri/i965/brw_draw.c        | 7 +++++--
 src/mesa/drivers/dri/i965/brw_draw_upload.c | 2 +-
 3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_context.h b/src/mesa/drivers/dri/i965/brw_context.h
index 9a4dd31..c6fb8d2 100644
--- a/src/mesa/drivers/dri/i965/brw_context.h
+++ b/src/mesa/drivers/dri/i965/brw_context.h
@@ -963,6 +963,7 @@ struct brw_context
       /* Summary of size and varying of active arrays, so we can check
        * for changes to this state:
        */
+      bool index_bounds_valid;
       unsigned int min_index, max_index;
 
       /* Offset from start of vertex buffer so we can avoid redefining
diff --git a/src/mesa/drivers/dri/i965/brw_draw.c b/src/mesa/drivers/dri/i965/brw_draw.c
index bb963f4..7901972 100644
--- a/src/mesa/drivers/dri/i965/brw_draw.c
+++ b/src/mesa/drivers/dri/i965/brw_draw.c
@@ -424,6 +424,7 @@ brw_try_draw_prims(struct gl_context *ctx,
                    const struct _mesa_prim *prims,
                    GLuint nr_prims,
                    const struct _mesa_index_buffer *ib,
+                   bool index_bounds_valid,
                    GLuint min_index,
                    GLuint max_index,
                    struct brw_transform_feedback_object *xfb_obj,
@@ -477,6 +478,7 @@ brw_try_draw_prims(struct gl_context *ctx,
    brw->ib.ib = ib;
    brw->ctx.NewDriverState |= BRW_NEW_INDICES;
 
+   brw->vb.index_bounds_valid = index_bounds_valid;
    brw->vb.min_index = min_index;
    brw->vb.max_index = max_index;
    brw->ctx.NewDriverState |= BRW_NEW_VERTICES;
@@ -659,14 +661,15 @@ brw_draw_prims(struct gl_context *ctx,
       perf_debug("Scanning index buffer to compute index buffer bounds.  "
                  "Use glDrawRangeElements() to avoid this.\n");
       vbo_get_minmax_indices(ctx, prims, ib, &min_index, &max_index, nr_prims);
+      index_bounds_valid = true;
    }
 
    /* Try drawing with the hardware, but don't do anything else if we can't
     * manage it.  swrast doesn't support our featureset, so we can't fall back
     * to it.
     */
-   brw_try_draw_prims(ctx, arrays, prims, nr_prims, ib, min_index, max_index,
-                      xfb_obj, stream, indirect);
+   brw_try_draw_prims(ctx, arrays, prims, nr_prims, ib, index_bounds_valid,
+                      min_index, max_index, xfb_obj, stream, indirect);
 }
 
 void
diff --git a/src/mesa/drivers/dri/i965/brw_draw_upload.c b/src/mesa/drivers/dri/i965/brw_draw_upload.c
index 5af4583..3ec37f8 100644
--- a/src/mesa/drivers/dri/i965/brw_draw_upload.c
+++ b/src/mesa/drivers/dri/i965/brw_draw_upload.c
@@ -493,7 +493,7 @@ brw_prepare_vertices(struct brw_context *brw)
                                           glarray->InstanceDivisor) - 1) +
                        glarray->_ElementSize);
             } else {
-               if (min_index == -1) {
+               if (!brw->vb.index_bounds_valid) {
                   offset = 0;
                   size = intel_buffer->Base.Size;
                } else {
-- 
2.5.0.400.gff86faf