Refactor: use 'BLI_task_parallel_range' in Draw Cache

One drawback to trying to predict the number of threads that will be
used in the `task_graph` is that we are only sure of the number when the
threads are running.

Using `BLI_task_parallel_range` allows the driver to
choose the best thread distribution through `parallel_reduce`.

The benefit is most evident on hardware with fewer cores.

This is the result on an 4-core laptop:
||before:|after:
|---|---|---|
|large_mesh_editing:|Average: 5.203638 FPS|Average: 5.398925 FPS
||rdata 15ms iter 43ms (frame 193ms)|rdata 14ms iter 36ms (frame 187ms)

Differential Revision: https://developer.blender.org/D11558

1 files changed, 2 insertions, 2 deletions

diff --git a/source/blender/gpu/tests/gpu_index_buffer_test.cc b/source/blender/gpu/tests/gpu_index_buffer_test.cc
index ebc110056e3..78e351af7f1 100644
--- a/source/blender/gpu/tests/gpu_index_buffer_test.cc
+++ b/source/blender/gpu/tests/gpu_index_buffer_test.cc
@@ -21,7 +21,7 @@ TEST_F(GPUTest, gpu_index_buffer_subbuilders)
 
   GPUIndexBufBuilder subbuilders[num_subbuilders];
   for (int subbuilder_index = 0; subbuilder_index < num_subbuilders; subbuilder_index++) {
-    GPU_indexbuf_subbuilder_init(&builder, &subbuilders[subbuilder_index]);
+    memcpy(&subbuilders[subbuilder_index], &builder, sizeof(builder));
   }
 
   for (int subbuilder_index = 0; subbuilder_index < num_subbuilders; subbuilder_index++) {
@@ -35,7 +35,7 @@ TEST_F(GPUTest, gpu_index_buffer_subbuilders)
 
   for (int subbuilder_index = 0; subbuilder_index < num_subbuilders; subbuilder_index++) {
     EXPECT_EQ(builder.index_len, subbuilder_index * verts_per_subbuilders);
-    GPU_indexbuf_subbuilder_finish(&builder, &subbuilders[subbuilder_index]);
+    GPU_indexbuf_join(&builder, &subbuilders[subbuilder_index]);
     EXPECT_EQ(builder.index_len, (subbuilder_index + 1) * verts_per_subbuilders);
   }