[Mesa-dev] [PATCH] draw/so: fix overflow calculation

[Zack Rusin]

only report overflow for missing targets if they're actually being
used. if the targets are missing but are not being used by any
slot in the stream output declaration we should correctly just
ignore them.

Signed-off-by: Zack Rusin <zackr at vmware.com>
---
 src/gallium/auxiliary/draw/draw_pt_so_emit.c |   26 ++++++++++++++++++--------
 1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/src/gallium/auxiliary/draw/draw_pt_so_emit.c b/src/gallium/auxiliary/draw/draw_pt_so_emit.c
index 1328e86..d024499 100644
--- a/src/gallium/auxiliary/draw/draw_pt_so_emit.c
+++ b/src/gallium/auxiliary/draw/draw_pt_so_emit.c
@@ -120,6 +120,7 @@ static void so_emit_prim(struct pt_so_emit *so,
    const struct pipe_stream_output_info *state = draw_so_info(draw);
    float *buffer;
    int buffer_total_bytes[PIPE_MAX_SO_BUFFERS];
+   unsigned buffer_written[PIPE_MAX_SO_BUFFERS] = {0};
 
    input_ptr = so->inputs;
    if (so->use_pre_clip_pos)
@@ -129,11 +130,12 @@ static void so_emit_prim(struct pt_so_emit *so,
 
    for (i = 0; i < draw->so.num_targets; i++) {
       struct draw_so_target *target = draw->so.targets[i];
-      /* If a buffer is missing then that's equivalent to
-       * an overflow */
-      if (!target)
-         return;
-      buffer_total_bytes[i] = target->internal_offset + target->target.buffer_offset;
+      if (target) {
+         buffer_total_bytes[i] = target->internal_offset +
+            target->target.buffer_offset;
+      } else {
+         buffer_total_bytes[i] = 0;
+      }
    }
 
    /* check have we space to emit prim first - if not don't do anything */
@@ -144,7 +146,11 @@ static void so_emit_prim(struct pt_so_emit *so,
          int ob = state->output[slot].output_buffer;
          unsigned dst_offset = state->output[slot].dst_offset * sizeof(float);
          unsigned write_size = num_comps * sizeof(float);
-
+         /* If a buffer is missing then that's equivalent to
+          * an overflow */
+         if (!draw->so.targets[ob]) {
+            return;
+         }
          if ((buffer_total_bytes[ob] + write_size + dst_offset) >
              draw->so.targets[ob]->target.buffer_size) {
             return;
@@ -173,6 +179,7 @@ static void so_emit_prim(struct pt_so_emit *so,
          unsigned num_comps = state->output[slot].num_components;
 
          ob = state->output[slot].output_buffer;
+         buffer_written[ob] = TRUE;
 
          buffer = (float *)((char *)draw->so.targets[ob]->mapping +
                             draw->so.targets[ob]->target.buffer_offset +
@@ -184,8 +191,11 @@ static void so_emit_prim(struct pt_so_emit *so,
             memcpy(buffer, &input[idx][start_comp], num_comps * sizeof(float));
       }
       for (ob = 0; ob < draw->so.num_targets; ++ob) {
-         draw->so.targets[ob]->internal_offset += state->stride[ob] * sizeof(float);
-         draw->so.targets[ob]->emitted_vertices += 1;
+         struct draw_so_target *target = draw->so.targets[ob];
+         if (target && buffer_written[ob]) {
+            target->internal_offset += state->stride[ob] * sizeof(float);
+            target->emitted_vertices += 1;
+         }
       }
    }
    so->emitted_vertices += num_vertices;
-- 
1.7.10.4