Spawning surfels uses a new shader pipeline (called `capture`) to avoid
the complexity of modifying the deferred or forward pipeline.
The shaders are light to compile and should only be compiled on bake.

This is very WIP: the surfel projection box is hardcoded and the 3
projections are done every frame. The surfels are placed in a regular
grid because of the raster pipeline used to spawn them.

Note: While this is really fast, I am not sure this will scale well for
highly detailed lighting conditions. In the case where the surfel density
is too low, the aliasing might create really poor result.

@@ -0,0 +30,4 @@
+class Instance;
+
+/* -------------------------------------------------------------------- */
+/** \name Cryptomatte

@@ -0,0 +50,4 @@
+class CubemapsModule {
+ private:
+  /** The max number of cubemaps to track. */
+  static constexpr int MaxCubemaps = 1;

@@ -65,0 +95,4 @@
+  side.cubemap_face_ps.framebuffer_set(&side.cubemap_face_fb);
+  side.cubemap_face_ps.state_set(DRW_STATE_WRITE_COLOR | DRW_STATE_DEPTH_ALWAYS);
+  side.cubemap_face_ps.material_set(manager, gpumat);
+

@@ -0,0 +52,4 @@
+}
+
+/* -------------------------------------------------------------------- */
+/** \name World

@@ -46,0 +55,4 @@
+
+  struct CubemapSide {
+    PassSimple cubemap_face_ps;
+    View view;

@@ -0,0 +1,16 @@
+void light_world_eval(ClosureDiffuse diffuse,

@@ -96,6 +96,7 @@
 /* Only during shadow rendering. */
 #define SHADOW_RENDER_MAP_SLOT 13
 #define RBUFS_UTILITY_TEX_SLOT 14
+#define REFLECTION_PROBE_TEX_SLOT 16

@@ -0,0 +7,4 @@
+  float lod = linear_roughness * lod_cube_max;
+
+  vec3 R = -reflect(V, reflection.N);
+  vec3 world_light = textureLod_cubemapArray(reflectionProbes, vec4(R, 0.0), lod).rgb;

@@ -59,0 +74,4 @@
+    side.cubemap_face_ps.state_set(DRW_STATE_WRITE_COLOR | DRW_STATE_DEPTH_ALWAYS);
+  }
+  const int2 extent(1);
+  constexpr eGPUTextureUsage usage = GPU_TEXTURE_USAGE_MEMORYLESS | GPU_TEXTURE_USAGE_SHADER_WRITE;

@@ -46,0 +53,4 @@
+ private:
+  Instance &inst_;
+
+  Texture dummy_renderpass_tx_;

@@ -46,0 +58,4 @@
+  Texture dummy_aov_color_tx_;
+  Texture dummy_aov_value_tx_;
+
+  struct CubemapSide {

@@ -46,0 +83,4 @@
+ public:
+  WorldProbePipeline(Instance &inst) : inst_(inst){};
+
+  void sync();

@@ -288,6 +338,7 @@ class UtilityTexture : public Texture {
 class PipelineModule {
  public:
   WorldPipeline world;

@@ -0,0 +43,4 @@
+{
+  if (cubemap.type == ReflectionProbe::Type::World) {
+    GPUMaterial *world_material = instance_.world.get_world_material();
+    instance_.pipelines.world_probe.sync(world_material);

@@ -0,0 +35,4 @@
+ * \{ */
+class ReflectionProbe {
+ public:
+  enum Type { Unused, World };

@@ -0,0 +46,4 @@
+class ReflectionProbeModule {
+ private:
+  /** The max number of probes to track. */
+  static constexpr int MAX_PROBES = 1;

@@ -0,0 +53,4 @@
+   *
+   * Must be a power of two; intension to be used as a cubemap atlas.
+   */
+  static constexpr int MAX_RESOLUTION = 2048;

@@ -0,0 +54,4 @@
+   * Must be a power of two; intension to be used as a cubemap atlas.
+   */
+  static constexpr int MAX_RESOLUTION = 2048;
+  static constexpr int MIPMAP_LEVELS = 12;

@@ -194,0 +195,4 @@
+
+void CaptureView::render()
+{
+  if (!world_capture_enable_) {

@@ -194,0 +210,4 @@
+
+    float4x4 view_m4 = cubeface_mat(face);
+    float4x4 win_m4;
+    cubeface_winmat_get(win_m4, 1.0f, 10.0f);