[Mesa-dev] [PATCH] st/mesa: rewrite the primitive restart fallback code
Brian Paul
brianp at vmware.com
Wed Nov 16 14:21:12 PST 2011
Previously we were mapping/unmapping the index buffer each time we
found the restart index in the buffer. This is bad when the restart
index is frequently used. Now just map the index buffer once, scan
it to produce a list of sub-primitives, unmap the buffer, then draw
the sub-primitives.
Also, clean up the logic of testing for indexed primitives and calling
handle_fallback_primitive_restart(). Don't call it for non-indexed
primitives.
---
src/mesa/state_tracker/st_draw.c | 224 +++++++++++++++++++++-----------------
1 files changed, 124 insertions(+), 100 deletions(-)
diff --git a/src/mesa/state_tracker/st_draw.c b/src/mesa/state_tracker/st_draw.c
index cb518e1..bb7decf 100644
--- a/src/mesa/state_tracker/st_draw.c
+++ b/src/mesa/state_tracker/st_draw.c
@@ -648,45 +648,89 @@ check_uniforms(struct gl_context *ctx)
}
}
-/** Helper code for primitive restart fallback */
-#define DO_DRAW(pipe, cur_start, cur_count) \
- do { \
- info.start = cur_start; \
- info.count = cur_count; \
- if (u_trim_pipe_prim(info.mode, &info.count)) { \
- if (transfer) \
- pipe_buffer_unmap(pipe, transfer); \
- pipe->draw_vbo(pipe, &info); \
- if (transfer) { \
- ptr = pipe_buffer_map(pipe, ibuffer->buffer, PIPE_TRANSFER_READ, &transfer); \
- assert(ptr != NULL); \
- ptr = ADD_POINTERS(ptr, ibuffer->offset); \
- } \
- } \
- } while(0)
-
-/** More helper code for primitive restart fallback */
-#define PRIM_RESTART_LOOP(elements) \
- do { \
- for (i = start; i < end; i++) { \
- if (elements[i] == info.restart_index) { \
- if (cur_count > 0) { \
- /* draw elts up to prev pos */ \
- DO_DRAW(pipe, cur_start, cur_count); \
- } \
- /* begin new prim at next elt */ \
- cur_start = i + 1; \
- cur_count = 0; \
- } \
- else { \
- cur_count++; \
+
+struct sub_primitive
+{
+ unsigned start, count;
+};
+
+
+/**
+ * Scan the elements array to find restart indexes. Return a list
+ * of primitive (start,count) pairs to indicate how to draw the sub-
+ * primitives delineated by the restart index.
+ */
+static struct sub_primitive *
+find_sub_primitives(const void *elements, unsigned element_size,
+ unsigned start, unsigned end, unsigned restart_index,
+ unsigned *num_sub_prims)
+{
+ const unsigned max_prims = end - start;
+ struct sub_primitive *sub_prims;
+ unsigned i, cur_start, cur_count, num;
+
+ sub_prims = (struct sub_primitive *)
+ malloc(max_prims * sizeof(struct sub_primitive));
+
+ if (!sub_prims) {
+ *num_sub_prims = 0;
+ return NULL;
+ }
+
+ cur_start = start;
+ cur_count = 0;
+ num = 0;
+
+#define SCAN_ELEMENTS(TYPE) \
+ for (i = start; i < end; i++) { \
+ if (((const TYPE *) elements)[i] == restart_index) { \
+ if (cur_count > 0) { \
+ assert(num < max_prims); \
+ sub_prims[num].start = cur_start; \
+ sub_prims[num].count = cur_count; \
+ num++; \
} \
+ cur_start = i + 1; \
+ cur_count = 0; \
} \
- if (cur_count > 0) { \
- DO_DRAW(pipe, cur_start, cur_count); \
+ else { \
+ cur_count++; \
} \
- } while (0)
+ } \
+ if (cur_count > 0) { \
+ assert(num < max_prims); \
+ sub_prims[num].start = cur_start; \
+ sub_prims[num].count = cur_count; \
+ num++; \
+ }
+ switch (element_size) {
+ case 1:
+ SCAN_ELEMENTS(ubyte);
+ break;
+ case 2:
+ SCAN_ELEMENTS(ushort);
+ break;
+ case 4:
+ SCAN_ELEMENTS(uint);
+ break;
+ default:
+ assert(0 && "bad index_size in find_sub_primitives()");
+ }
+
+#undef SCAN_ELEMENTS
+
+ *num_sub_prims = num;
+
+ return sub_prims;
+}
+
+
+/**
+ * For gallium drivers that don't support the primitive restart
+ * feature, handle it here by breaking up the indexed primitive into
+ * sub-primitives.
+ */
static void
handle_fallback_primitive_restart(struct pipe_context *pipe,
const struct _mesa_index_buffer *ib,
@@ -698,75 +742,57 @@ handle_fallback_primitive_restart(struct pipe_context *pipe,
const unsigned end = start + count;
struct pipe_draw_info info = *orig_info;
struct pipe_transfer *transfer = NULL;
- unsigned instance, i, cur_start, cur_count;
- const void *ptr;
-
- info.primitive_restart = FALSE;
+ unsigned instance, i;
+ const void *ptr = NULL;
+ struct sub_primitive *sub_prims;
+ unsigned num_sub_prims;
- if (!info.indexed) {
- /* Splitting the draw arrays call is handled by the VBO module */
- if (u_trim_pipe_prim(info.mode, &info.count))
- pipe->draw_vbo(pipe, &info);
+ assert(info.indexed);
+ assert(ibuffer->buffer);
+ assert(ib);
+ if (!ibuffer->buffer || !ib)
return;
- }
- /* info.indexed == TRUE */
- assert(ibuffer);
- assert(ibuffer->buffer);
+ info.primitive_restart = FALSE;
+ info.instance_count = 1;
- if (ib) {
- struct gl_buffer_object *bufobj = ib->obj;
- if (bufobj && bufobj->Name) {
- ptr = NULL;
- }
- else {
- ptr = ib->ptr;
- }
- } else {
- ptr = NULL;
+ if (ib->obj && _mesa_is_bufferobj(ib->obj)) {
+ ptr = pipe_buffer_map(pipe, ibuffer->buffer,
+ PIPE_TRANSFER_READ, &transfer);
+ }
+ else {
+ ptr = ib->ptr;
}
if (!ptr)
- ptr = pipe_buffer_map(pipe, ibuffer->buffer, PIPE_TRANSFER_READ, &transfer);
+ return;
- if (!ptr)
- return;
ptr = ADD_POINTERS(ptr, ibuffer->offset);
- /* Need to loop over instances as well to preserve draw order */
+ sub_prims = find_sub_primitives(ptr, ibuffer->index_size,
+ start, end, orig_info->restart_index,
+ &num_sub_prims);
+
+ if (transfer)
+ pipe_buffer_unmap(pipe, transfer);
+
+ /* Now draw the sub primitives.
+ * Need to loop over instances as well to preserve draw order.
+ */
for (instance = 0; instance < orig_info->instance_count; instance++) {
info.start_instance = instance + orig_info->start_instance;
- info.instance_count = 1;
- cur_start = start;
- cur_count = 0;
-
- switch (ibuffer->index_size) {
- case 1:
- {
- const ubyte *elt_ub = (const ubyte *)ptr;
- PRIM_RESTART_LOOP(elt_ub);
- }
- break;
- case 2:
- {
- const ushort *elt_us = (const ushort *)ptr;
- PRIM_RESTART_LOOP(elt_us);
- }
- break;
- case 4:
- {
- const uint *elt_ui = (const uint *)ptr;
- PRIM_RESTART_LOOP(elt_ui);
+ for (i = 0; i < num_sub_prims; i++) {
+ info.start = sub_prims[i].start;
+ info.count = sub_prims[i].count;
+ if (u_trim_pipe_prim(info.mode, &info.count)) {
+ pipe->draw_vbo(pipe, &info);
}
- break;
- default:
- assert(0 && "bad index_size in handle_fallback_primitive_restart()");
}
}
- if (transfer)
- pipe_buffer_unmap(pipe, transfer);
+ if (sub_prims)
+ free(sub_prims);
}
@@ -978,10 +1004,13 @@ st_draw_vbo(struct gl_context *ctx,
info.min_index = min_index;
info.max_index = max_index;
}
- }
- info.primitive_restart = ctx->Array.PrimitiveRestart;
- info.restart_index = ctx->Array.RestartIndex;
+ /* The VBO module handles restart for the non-indexed GLDrawArrays
+ * so we only set these fields for indexed drawing:
+ */
+ info.primitive_restart = ctx->Array.PrimitiveRestart;
+ info.restart_index = ctx->Array.RestartIndex;
+ }
/* do actual drawing */
for (i = 0; i < nr_prims; i++) {
@@ -996,19 +1025,14 @@ st_draw_vbo(struct gl_context *ctx,
}
if (info.primitive_restart) {
- /*
- * Handle primitive restart for drivers that doesn't support it.
- *
- * The VBO module handles restart inside of draw_arrays for us,
- * but we should still remove the primitive_restart flag on the
- * info struct, the fallback function does this for us. Just
- * remove the flag for all drivers in this case as well.
- */
- if (st->sw_primitive_restart || !info.indexed)
+ if (st->sw_primitive_restart) {
+ /* Handle primitive restart for drivers that doesn't support it */
handle_fallback_primitive_restart(pipe, ib, &ibuffer, &info);
- else
+ }
+ else {
/* don't trim, restarts might be inside index list */
pipe->draw_vbo(pipe, &info);
+ }
}
else if (u_trim_pipe_prim(info.mode, &info.count))
pipe->draw_vbo(pipe, &info);
--
1.7.3.4
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