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-rw-r--r--src/gallium/auxiliary/draw/draw_pt.c20
-rw-r--r--src/gallium/auxiliary/util/u_draw.c32
2 files changed, 39 insertions, 13 deletions
diff --git a/src/gallium/auxiliary/draw/draw_pt.c b/src/gallium/auxiliary/draw/draw_pt.c
index e0eda67c1a2..080e03dd46f 100644
--- a/src/gallium/auxiliary/draw/draw_pt.c
+++ b/src/gallium/auxiliary/draw/draw_pt.c
@@ -422,6 +422,7 @@ draw_vbo(struct draw_context *draw,
{
unsigned reduced_prim = u_reduced_prim(info->mode);
unsigned instance;
+ unsigned index_limit;
assert(info->instance_count > 0);
if (info->indexed)
@@ -470,11 +471,20 @@ draw_vbo(struct draw_context *draw,
if (0)
draw_print_arrays(draw, info->mode, info->start, MIN2(info->count, 20));
- draw->pt.max_index = util_draw_max_index(draw->pt.vertex_buffer,
- draw->pt.nr_vertex_buffers,
- draw->pt.vertex_element,
- draw->pt.nr_vertex_elements,
- info);
+ index_limit = util_draw_max_index(draw->pt.vertex_buffer,
+ draw->pt.nr_vertex_buffers,
+ draw->pt.vertex_element,
+ draw->pt.nr_vertex_elements,
+ info);
+
+ if (index_limit == 0) {
+ /* one of the buffers is too small to do any valid drawing */
+ debug_warning("draw: VBO too small to draw anything\n");
+ return;
+ }
+
+ draw->pt.max_index = index_limit - 1;
+
/*
* TODO: We could use draw->pt.max_index to further narrow
diff --git a/src/gallium/auxiliary/util/u_draw.c b/src/gallium/auxiliary/util/u_draw.c
index 20837be5e59..d16575b7340 100644
--- a/src/gallium/auxiliary/util/u_draw.c
+++ b/src/gallium/auxiliary/util/u_draw.c
@@ -33,9 +33,13 @@
/**
- * Returns the largest legal index value for the current set of bound vertex
- * buffers. Regardless of any other consideration, all vertex lookups need to
- * be clamped to 0..max_index to prevent an out-of-bound access.
+ * Returns the largest legal index value plus one for the current set
+ * of bound vertex buffers. Regardless of any other consideration,
+ * all vertex lookups need to be clamped to 0..max_index-1 to prevent
+ * an out-of-bound access.
+ *
+ * Note that if zero is returned it means that one or more buffers is
+ * too small to contain any valid vertex data.
*/
unsigned
util_draw_max_index(
@@ -48,7 +52,7 @@ util_draw_max_index(
unsigned max_index;
unsigned i;
- max_index = ~0;
+ max_index = ~0U - 1;
for (i = 0; i < nr_vertex_elements; i++) {
const struct pipe_vertex_element *element =
&vertex_elements[i];
@@ -68,13 +72,25 @@ util_draw_max_index(
assert(format_desc->block.bits % 8 == 0);
format_size = format_desc->block.bits/8;
- assert(buffer_size - buffer->buffer_offset <= buffer_size);
+ if (buffer->buffer_offset >= buffer_size) {
+ /* buffer is too small */
+ return 0;
+ }
+
buffer_size -= buffer->buffer_offset;
- assert(buffer_size - element->src_offset <= buffer_size);
+ if (element->src_offset >= buffer_size) {
+ /* buffer is too small */
+ return 0;
+ }
+
buffer_size -= element->src_offset;
- assert(buffer_size - format_size <= buffer_size);
+ if (format_size > buffer_size) {
+ /* buffer is too small */
+ return 0;
+ }
+
buffer_size -= format_size;
if (buffer->stride != 0) {
@@ -95,5 +111,5 @@ util_draw_max_index(
}
}
- return max_index;
+ return max_index + 1;
}