Frame: Dynamically balance catalog splats

src/frame.c

@@ -333,10 +333,15 @@ size_t frame_splat_catalog(const FrameLensMesh *mesh,
 #pragma omp parallel num_threads((int)worker_count) reduction(+ : images)
   {
     const size_t worker = (size_t)omp_get_thread_num();
-    const size_t first = mesh->triangle_count * worker / worker_count;
-    const size_t last = mesh->triangle_count * (worker + 1) / worker_count;
-    images += splat_catalog_triangles(mesh, catalog, private_hdr[worker], width,
-                                      height, exposure, psf, first, last);
+    /* Source density and lens magnification can vary by orders of magnitude
+     * between neighboring image triangles.  Dynamic single-triangle chunks
+     * prevent a small sky region from leaving the other private HDR workers
+     * idle.  Each worker still owns its HDR buffer exclusively. */
+#pragma omp for schedule(dynamic, 1)
+    for (size_t triangle = 0; triangle < mesh->triangle_count; ++triangle)
+      images += splat_catalog_triangles(mesh, catalog, private_hdr[worker],
+                                        width, height, exposure, psf, triangle,
+                                        triangle + 1);
   }
 #pragma omp parallel for schedule(static)
   for (size_t pixel = 0; pixel < pixel_count; ++pixel)