This reverts commit 073764391eb4aa8cb868946d37d6f2f716cb30d6.

@@ -319,3 +319,3 @@
     bl_label = "Volumetrics"
     bl_options = {'DEFAULT_CLOSED'}
-    COMPAT_ENGINES = {'BLENDER_EEVEE'}
+    COMPAT_ENGINES = {'BLENDER_EEVEE', 'BLENDER_EEVEE_NEXT'}

@@ -0,0 +8,4 @@
+
+class Instance;
+
+class Volumes {

@@ -191,3 +191,3 @@
 #  endif
 
-vec3 g_orco;
+/** WARNING: these are not attributes, these are global vars. */

@@ -116,3 +130,3 @@
 Closure closure_eval(ClosureVolumeScatter volume_scatter)
 {
-  /* TODO */
+  SELECT_CLOSURE(g_volume_scatter_data, g_volume_scatter_rand, volume_scatter);

@@ -211,3 +227,3 @@
 void attrib_load();
 Closure nodetree_surface();
-Closure nodetree_volume();
+/* Closure nodetree_volume(); */

@@ -115,2 +116,4 @@
 #endif
 
+#ifdef MAT_TRANSPARENT
+  /* Volumes Integration */

@@ -0,0 +25,4 @@
+  vec3 ndc_cell = volume_to_ndc(vec3(uvs, 1e-5));
+  vec3 view_cell = get_view_space_from_depth(ndc_cell.xy, ndc_cell.z);
+
+  /* Ortho */

@@ -0,0 +60,4 @@
+    froxel_scattering = (froxel_scattering * (1.0f - froxel_transmittance)) /
+                        max(vec3(1e-8), extinction);
+
+    /* accumulate and also take into account the transmittance from previous steps */

@@ -0,0 +110,4 @@
+  return ld.color * ld.volume_power * power;
+}
+
+vec3 light_volume_light_vector(LightData ld, vec3 P)

@@ -0,0 +4,4 @@
+/* Based on Frosbite Unified Volumetric.
+ * https://www.ea.com/frostbite/news/physically-based-unified-volumetric-rendering-in-frostbite */
+
+/* Step 4 : Apply final integration on top of the scene color. */

@@ -0,0 +63,4 @@
+  vec3 V = cameraVec(P);
+
+  vec2 phase = texelFetch(phase_tx, froxel, 0).rg;
+  float s_anisotropy = phase.x / max(1.0, phase.y);

@@ -0,0 +65,4 @@
+  vec2 phase = texelFetch(phase_tx, froxel, 0).rg;
+  float s_anisotropy = phase.x / max(1.0, phase.y);
+
+  /* Environment : Average color. */

@@ -192,0 +204,4 @@
+                     "eevee_light_data",
+                     "eevee_shadow_data",
+                     "eevee_sampling_data",
+                     //"eevee_aov_out",

@@ -0,0 +57,4 @@
+    .image(1, GPU_R11F_G11F_B10F, Qualifier::WRITE, ImageType::FLOAT_3D, "out_transmittance")
+    .do_static_compilation(true);
+
+GPU_SHADER_CREATE_INFO(eevee_volume_resolve_common)

@@ -0,0 +65,4 @@
+
+GPU_SHADER_CREATE_INFO(eevee_volume_resolve)
+    .additional_info("eevee_volume_resolve_common")
+    .fragment_out(0, Type::VEC4, "out_radiance", DualBlend::SRC_0)

@@ -88,1 +88,4 @@
 
+/* Volumes. */
+#define VOLUME_GROUP_SIZE 4
+#define VOLUME_2D_GROUP_SIZE 8

@@ -426,0 +427,4 @@
+/** \name Volumes
+ * \{ */
+
+struct VolumesData {

@@ -0,0 +1,401 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */

@@ -0,0 +3,4 @@
+/** \file
+ * \ingroup draw_engine
+ *
+ * Volumetric effects rendering using frostbite approach.

@@ -0,0 +50,4 @@
+
+namespace blender::eevee {
+
+bool VolumeModule::GridAABB::init(Object *ob, const Camera &camera, const VolumesDataBuf &data)

@@ -0,0 +52,4 @@
+
+bool VolumeModule::GridAABB::init(Object *ob, const Camera &camera, const VolumesDataBuf &data)
+{
+  auto to_global_grid_coords = [&](float3 wP) -> int3 {

@@ -0,0 +83,4 @@
+  max = int3(INT32_MIN);
+
+  for (float3 corner : bbox.vec) {
+    corner = (float4x4(ob->object_to_world) * float4(corner, 1.0)).xyz();

@@ -0,0 +118,4 @@
+
+  const Scene *scene_eval = inst_.scene;
+
+  const float3 viewport_size = DRW_viewport_size_get();

@@ -0,0 +189,4 @@
+  sync_world();
+}
+
+void VolumeModule::sync_world()

@@ -0,0 +217,4 @@
+  }
+  else {
+    /* If no world or volume material is present just clear the buffer. */
+    ps.shader_set(inst_.shaders.static_shader_get(VOLUME_CLEAR));

@@ -0,0 +320,4 @@
+
+    float4 scatter = float4(0.0f);
+    float4 transmit = float4(1.0f);
+    dummy_scatter_tx_.ensure_3d(GPU_RGBA8, int3(1), GPU_TEXTURE_USAGE_SHADER_READ, scatter);

@@ -0,0 +6,4 @@
+ * https://www.ea.com/frostbite/news/physically-based-unified-volumetric-rendering-in-frostbite */
+
+/* Volume slice to view space depth. */
+float volume_z_to_view_z(float z)

@@ -0,0 +12,4 @@
+
+namespace blender::draw {
+
+bool volume_sub_pass(PassMain::Sub &ps, Scene *scene, Object *ob, GPUMaterial *gpu_material);

@@ -0,0 +13,4 @@
+namespace blender::draw {
+
+bool volume_sub_pass(PassMain::Sub &ps, Scene *scene, Object *ob, GPUMaterial *gpu_material);
+bool volume_sub_pass(PassSimple::Sub &ps, Scene *scene, Object *ob, GPUMaterial *gpu_material);

@@ -439,0 +473,4 @@
+  }
+}
+
+static inline float view_z_to_volume_z(

@@ -0,0 +60,4 @@
+    const float4x4 &view_matrix = camera.data_get().viewmat;
+    const float4x4 &perspective_matrix = camera.data_get().winmat * view_matrix;
+
+    /** NOTE: Keep in sync with ndc_to_volume. */

@@ -0,0 +233,4 @@
+    return;
+  }
+
+  PassMain::Sub *ps = volume_sub_pass(

@@ -0,0 +56,4 @@
+
+  /* Light Scattering. */
+  PassSimple scatter_ps_ = {"Volumes.Scatter"};
+  Framebuffer scatter_fb_;

@@ -0,0 +8,4 @@
+/* Volume slice to view space depth. */
+float volume_z_to_view_z(float z)
+{
+  float near = volumes_info_buf.depth_near;

@@ -0,0 +16,4 @@
+  return volume_z_to_view_z(near, far, distribution, is_persp, z);
+}
+
+float view_z_to_volume_z(float depth)

@@ -0,0 +35,4 @@
+  return coord;
+}
+
+vec3 ndc_to_volume(vec3 coord)

@@ -0,0 +44,4 @@
+  return coord;
+}
+
+float phase_function_isotropic()

@@ -0,0 +49,4 @@
+  return 1.0 / (4.0 * M_PI);
+}
+
+float phase_function(vec3 v, vec3 l, float g)

@@ -116,8 +118,9 @@ class Instance {
         render_buffers(*this),
         main_view(*this),
         world(*this),
+        irradiance_cache(*this),

@@ -230,6 +238,7 @@ void Instance::object_sync(Object *ob)
       case OB_POINTCLOUD:
         sync.sync_point_cloud(ob, ob_handle, res_handle, ob_ref);

@@ -276,2 +271,4 @@
                                  eMaterialGeometry geometry_type,
                                  bool probe_capture = false);
+
+ private:

@@ -110,0 +120,4 @@
+  world_ps_.state_set(DRW_STATE_WRITE_COLOR);
+  inst_.volume.bind_properties_buffers(world_ps_);
+  inst_.lights.bind_resources(&world_ps_);
+  inst_.shadows.bind_resources(&world_ps_);

@@ -407,4 +434,2 @@
     info.vertex_source_generated = vert_gen.str();
-  }
 
-  {

@@ -393,0 +405,4 @@
+  if (do_vertex_attrib_load) {
+    vert_gen << global_vars.str() << attr_load.str();
+  }
+  else if (pipeline_type != MAT_PIPE_VOLUME) {

@@ -539,2 +557,2 @@
-                               codegen_callback,
-                               this);
+  return DRW_shader_from_world(
+      blender_world, nodetree, shader_uuid, is_volume, false, codegen_callback, this);

@@ -93,13 +93,17 @@ enum eShaderType {
   SHADOW_TILEMAP_TAG_USAGE_SURFELS,
   SHADOW_TILEMAP_TAG_USAGE_TRANSPARENT,
 
-  SUBSURFACE_EVAL,

@@ -442,0 +453,4 @@
+  float light_clamp;
+  packed_float3 inv_tex_size;
+  float shadow_steps;
+  int use_lights;

@@ -132,0 +133,4 @@
+  inst_.pipelines.forward.render_opaque(
+      render_view_new_, prepass_fb_, combined_fb_, rbufs.combined_tx);
+
+  inst_.volume.draw_resolve(render_view_new_);

@@ -0,0 +206,4 @@
+  }
+
+  float3x3 world_matrix = float3x3(float4x4(ob->object_to_world));
+  float3 size = math::to_scale(world_matrix);

@@ -0,0 +354,4 @@
+  DRW_stats_group_end();
+}
+
+void VolumeModule::draw_resolve(View &view)

@@ -61,3 +60,4 @@
   World(Instance &inst) : inst_(inst){};
   ~World();
 
+  ::World *default_world_get();

@@ -0,0 +1,16 @@
+
+void main()

@@ -0,0 +64,4 @@
+#endif
+
+  g_data = init_globals(wP);
+#ifndef NO_ATTRIB_LOAD

@@ -108,3 +108,3 @@
       BoundBox &bbox = *BKE_volume_boundbox_get(ref.object);
       orco_add = (float3(bbox.vec[6]) + float3(bbox.vec[0])) * 0.5f; /* Center. */
-      orco_mul = float3(bbox.vec[6]) - float3(bbox.vec[0]);          /* Size. */
+      orco_mul = (float3(bbox.vec[6]) - float3(bbox.vec[0])) * 0.5f; /* Size. */