1 files changed, 56 insertions, 0 deletions
diff --git a/source/blender/draw/engines/eevee_next/shaders/eevee_light_culling_zbin_comp.glsl b/source/blender/draw/engines/eevee_next/shaders/eevee_light_culling_zbin_comp.glsl
new file mode 100644
index 00000000000..ae20153f26c
--- /dev/null
+++ b/source/blender/draw/engines/eevee_next/shaders/eevee_light_culling_zbin_comp.glsl
@@ -0,0 +1,56 @@
+
+/**
+ * Create the Zbins from Z-sorted lights.
+ * Perform min-max operation in LDS memory for speed.
+ * For this reason, we only dispatch 1 thread group.
+ */
+
+#pragma BLENDER_REQUIRE(common_view_lib.glsl)
+#pragma BLENDER_REQUIRE(eevee_light_iter_lib.glsl)
+
+/* Fits the limit of 32KB. */
+shared uint zbin_max[CULLING_ZBIN_COUNT];
+shared uint zbin_min[CULLING_ZBIN_COUNT];
+
+void main()
+{
+  const uint zbin_iter = CULLING_ZBIN_COUNT / gl_WorkGroupSize.x;
+  const uint zbin_local = gl_LocalInvocationID.x * zbin_iter;
+
+  uint src_index = gl_GlobalInvocationID.x;
+
+  for (uint i = 0u, l = zbin_local; i < zbin_iter; i++, l++) {
+    zbin_max[l] = 0x0u;
+    zbin_min[l] = ~0x0u;
+  }
+  barrier();
+
+  uint light_iter = divide_ceil(light_cull_buf.visible_count, gl_WorkGroupSize.x);
+  for (uint i = 0u; i < light_iter; i++) {
+    uint index = i * gl_WorkGroupSize.x + gl_LocalInvocationID.x;
+    if (index >= light_cull_buf.visible_count) {
+      continue;
+    }
+    vec3 P = light_buf[index]._position;
+    /* TODO(fclem): Could have better bounds for spot and area lights. */
+    float radius = light_buf[index].influence_radius_max;
+    float z_dist = dot(cameraForward, P) - dot(cameraForward, cameraPos);
+    int z_min = culling_z_to_zbin(
+        light_cull_buf.zbin_scale, light_cull_buf.zbin_bias, z_dist + radius);
+    int z_max = culling_z_to_zbin(
+        light_cull_buf.zbin_scale, light_cull_buf.zbin_bias, z_dist - radius);
+    z_min = clamp(z_min, 0, CULLING_ZBIN_COUNT - 1);
+    z_max = clamp(z_max, 0, CULLING_ZBIN_COUNT - 1);
+    /* Register to Z bins. */
+    for (int z = z_min; z <= z_max; z++) {
+      atomicMin(zbin_min[z], index);
+      atomicMax(zbin_max[z], index);
+    }
+  }
+  barrier();
+
+  /* Write result to zbins buffer. Pack min & max into 1 uint. */
+  for (uint i = 0u, l = zbin_local; i < zbin_iter; i++, l++) {
+    out_zbin_buf[l] = (zbin_max[l] << 16u) | (zbin_min[l] & 0xFFFFu);
+  }
+}