Reconsider larger workgroups again.

Themaister · Jan 13, 2024 · 1ea6798 · 1ea6798
1 parent 7ddc4d3
commit 1ea6798
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Showing 2 changed files with 16 additions and 4 deletions.
diff --git a/assets/shaders/inc/meshlet_primitive_cull.h b/assets/shaders/inc/meshlet_primitive_cull.h
@@ -165,7 +165,15 @@ void meshlet_init_shared()
 
 uint meshlet_get_meshlet_index()
 {
-	return gl_WorkGroupID.y;
+	return gl_WorkGroupSize.y == 8 ? gl_WorkGroupID.x : gl_WorkGroupID.y;
+}
+
+uint meshlet_get_sublet_index(uint meshlet_index, uint sublet_index)
+{
+	if (gl_WorkGroupSize.y == 8)
+		return 8u * meshlet_index + sublet_index;
+	else
+		return 8u * meshlet_index + gl_WorkGroupSize.y * gl_WorkGroupID.x + sublet_index;
 }
 
 void meshlet_emit_primitive(uvec3 prim, vec4 clip_pos, vec4 viewport)

diff --git a/tests/assets/shaders/meshlet_debug_plain.mesh b/tests/assets/shaders/meshlet_debug_plain.mesh
@@ -120,12 +120,16 @@ void main()
 #endif
 
 #if defined(MESHLET_PRIMITIVE_CULL_WAVE32) && MESHLET_PRIMITIVE_CULL_WAVE32
-    uint linear_index = gl_SubgroupID * gl_SubgroupSize + gl_SubgroupInvocationID;
+    uint linear_index = gl_SubgroupInvocationID;
+    uint sublet_index = gl_SubgroupID;
 #else
-    uint linear_index = gl_LocalInvocationIndex;
+    uint linear_index = gl_LocalInvocationID.x;
+    uint sublet_index = gl_LocalInvocationID.y;
 #endif
 
-    IndirectDrawMesh meshlet = indirect_commands_mesh.draws[8u * task.meshlet_index + gl_WorkGroupID.x];
+    sublet_index = meshlet_get_sublet_index(task.meshlet_index, sublet_index);
+    IndirectDrawMesh meshlet = indirect_commands_mesh.draws[sublet_index];
+
     mat4 M = transforms.data[task.node_offset];
 
     // Transform positions.