EEVEE: Port back HiZbuffer

Pretty much identical.

Texture format is now always `GPU_R32F` to remove some workarounds.

16 files changed, 395 insertions, 60 deletions

diff --git a/source/blender/draw/CMakeLists.txt b/source/blender/draw/CMakeLists.txt
index f102141e7d2..e0343cffb01 100644
--- a/source/blender/draw/CMakeLists.txt
+++ b/source/blender/draw/CMakeLists.txt
@@ -120,6 +120,7 @@ set(SRC
   engines/eevee/eevee_film.cc
   engines/eevee/eevee_gpencil.cc
   engines/eevee/eevee_hair.cc
+  engines/eevee/eevee_hizbuffer.cc
   engines/eevee/eevee_id_map.cc
   engines/eevee/eevee_instance.cc
   engines/eevee/eevee_light.cc
@@ -253,6 +254,8 @@ data_to_c_simple(engines/eevee/shaders/eevee_deferred_holdout_frag.glsl SRC)
 data_to_c_simple(engines/eevee/shaders/eevee_deferred_transparent_frag.glsl SRC)
 data_to_c_simple(engines/eevee/shaders/eevee_deferred_volume_frag.glsl SRC)
 data_to_c_simple(engines/eevee/shaders/eevee_depth_clear_frag.glsl SRC)
+data_to_c_simple(engines/eevee/shaders/eevee_hiz_copy_frag.glsl SRC)
+data_to_c_simple(engines/eevee/shaders/eevee_hiz_downsample_frag.glsl SRC)
 data_to_c_simple(engines/eevee/shaders/eevee_depth_of_field_accumulator_lib.glsl SRC)
 data_to_c_simple(engines/eevee/shaders/eevee_depth_of_field_bokeh_lut_frag.glsl SRC)
 data_to_c_simple(engines/eevee/shaders/eevee_depth_of_field_filter_frag.glsl SRC)
diff --git a/source/blender/draw/engines/eevee/eevee_hizbuffer.cc b/source/blender/draw/engines/eevee/eevee_hizbuffer.cc
new file mode 100644
index 00000000000..24f0c8261e8
--- /dev/null
+++ b/source/blender/draw/engines/eevee/eevee_hizbuffer.cc
@@ -0,0 +1,101 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * Copyright 2021, Blender Foundation.
+ */
+
+/** \file
+ * \ingroup eevee
+ *
+ * The Hierarchical-Z buffer is texture containing a copy of the depth buffer with mipmaps.
+ * Each mip contains the maximum depth of each 4 pixels on the upper level.
+ * The size of the texture is padded to avoid messing with the mipmap pixels alignments.
+ */
+
+#include "eevee_instance.hh"
+
+#include "eevee_hizbuffer.hh"
+
+namespace blender::eevee {
+
+/* -------------------------------------------------------------------- */
+/** \name Hierarchical-Z buffer
+ *
+ * \{ */
+
+void HiZBufferModule::sync(void)
+{
+  {
+    hiz_copy_ps_ = DRW_pass_create("HizCopy", DRW_STATE_WRITE_COLOR);
+    GPUShader *sh = inst_.shaders.static_shader_get(HIZ_COPY);
+    DRWShadingGroup *grp = DRW_shgroup_create(sh, hiz_copy_ps_);
+    DRW_shgroup_uniform_texture_ref(grp, "depth_tx", &input_depth_tx_);
+    DRW_shgroup_call_procedural_triangles(grp, nullptr, 1);
+  }
+  {
+    hiz_downsample_ps_ = DRW_pass_create("HizDownsample", DRW_STATE_WRITE_COLOR);
+    GPUShader *sh = inst_.shaders.static_shader_get(HIZ_DOWNSAMPLE);
+    DRWShadingGroup *grp = DRW_shgroup_create(sh, hiz_downsample_ps_);
+    DRW_shgroup_uniform_texture_ref(grp, "depth_tx", &input_depth_tx_);
+    DRW_shgroup_uniform_vec2(grp, "texel_size", texel_size_, 1);
+    DRW_shgroup_call_procedural_triangles(grp, nullptr, 1);
+  }
+}
+
+void HiZBuffer::prepare(GPUTexture *depth_src_tx)
+{
+  int div = 1 << mip_count_;
+  vec2 extent_src(GPU_texture_width(depth_src_tx), GPU_texture_height(depth_src_tx));
+  vec2 extent_hiz(divide_ceil_u(extent_src.x, div) * div, divide_ceil_u(extent_src.y, div) * div);
+
+  inst_.hiz.texel_size_ = 1.0f / extent_hiz;
+  inst_.hiz.data_.uv_scale = extent_src / extent_hiz;
+
+  inst_.hiz.data_.push_update();
+
+  /* TODO/OPTI(fclem): Share it between similar views.
+   * Not possible right now because request_tmp does not support mipmaps. */
+  hiz_tx_.ensure("HiZ", UNPACK2(extent_hiz), mip_count_, GPU_R32F);
+  hiz_fb_.ensure(GPU_ATTACHMENT_NONE, GPU_ATTACHMENT_TEXTURE(hiz_tx_));
+
+  GPU_texture_mipmap_mode(hiz_tx_, true, false);
+}
+
+void HiZBuffer::recursive_downsample(void *thunk, int UNUSED(lvl))
+{
+  HiZBufferModule &hiz = *reinterpret_cast<HiZBufferModule *>(thunk);
+  hiz.texel_size_ *= 2.0f;
+  DRW_draw_pass(hiz.hiz_downsample_ps_);
+}
+
+void HiZBuffer::update(GPUTexture *depth_src_tx)
+{
+  DRW_stats_group_start("Hiz");
+
+  inst_.hiz.texel_size_ = 1.0f / vec2(GPU_texture_width(hiz_tx_), GPU_texture_height(hiz_tx_));
+
+  inst_.hiz.input_depth_tx_ = depth_src_tx;
+  GPU_framebuffer_bind(hiz_fb_);
+  DRW_draw_pass(inst_.hiz.hiz_copy_ps_);
+
+  inst_.hiz.input_depth_tx_ = hiz_tx_;
+  GPU_framebuffer_recursive_downsample(hiz_fb_, mip_count_, &recursive_downsample, &inst_.hiz);
+
+  DRW_stats_group_end();
+}
+
+/** \} */
+
+}  // namespace blender::eevee
diff --git a/source/blender/draw/engines/eevee/eevee_hizbuffer.hh b/source/blender/draw/engines/eevee/eevee_hizbuffer.hh
new file mode 100644
index 00000000000..80bd7be912c
--- /dev/null
+++ b/source/blender/draw/engines/eevee/eevee_hizbuffer.hh
@@ -0,0 +1,103 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * Copyright 2021, Blender Foundation.
+ */
+
+/** \file
+ * \ingroup eevee
+ *
+ * The Hierarchical-Z buffer is texture containing a copy of the depth buffer with mipmaps.
+ * Each mip contains the maximum depth of each 4 pixels on the upper level.
+ * The size of the texture is padded to avoid messing with the mipmap pixels alignments.
+ */
+
+#pragma once
+
+#include "DRW_render.h"
+
+#include "eevee_shader_shared.hh"
+
+namespace blender::eevee {
+
+class Instance;
+
+/* -------------------------------------------------------------------- */
+/** \name Hierarchical-Z buffer
+ * \{ */
+
+class HiZBuffer {
+ private:
+  Instance &inst_;
+  /** Framebuffer use for recursive downsampling. */
+  /* TODO(fclem) Remove this and use a compute shader instead. */
+  Framebuffer hiz_fb_ = Framebuffer("DepthHiz");
+  /** Max mip to downsample to. We ensure the hiz has enough padding to never
+   * have to compensate the mipmap alignments. */
+  constexpr static int mip_count_ = 6;
+  /** TODO/OPTI(fclem): Share it between similar views. */
+  Texture hiz_tx_;
+
+ public:
+  HiZBuffer(Instance &inst) : inst_(inst){};
+
+  void prepare(GPUTexture *depth_src);
+  void update(GPUTexture *depth_src);
+
+  GPUTexture *texture_get(void) const
+  {
+    return hiz_tx_;
+  }
+
+ private:
+  static void recursive_downsample(void *thunk, int lvl);
+};
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Hierarchical-Z buffer Module
+ * \{ */
+
+class HiZBufferModule {
+  friend HiZBuffer;
+
+ private:
+  Instance &inst_;
+
+  HiZDataBuf data_;
+  /** Copy input depth to hiz-buffer with border padding. */
+  DRWPass *hiz_copy_ps_;
+  /** Downsample one mipmap level. */
+  DRWPass *hiz_downsample_ps_;
+  /** References only. */
+  GPUTexture *input_depth_tx_ = nullptr;
+  /** Pixel size of the render target during hiz downsampling. */
+  vec2 texel_size_;
+
+ public:
+  HiZBufferModule(Instance &inst) : inst_(inst){};
+
+  void sync(void);
+
+  const GPUUniformBuf *ubo_get(void) const
+  {
+    return data_.ubo_get();
+  }
+};
+
+/** \} */
+
+}  // namespace blender::eevee
diff --git a/source/blender/draw/engines/eevee/eevee_instance.cc b/source/blender/draw/engines/eevee/eevee_instance.cc
index 9aea6e301af..8c042ae062b 100644
--- a/source/blender/draw/engines/eevee/eevee_instance.cc
+++ b/source/blender/draw/engines/eevee/eevee_instance.cc
@@ -125,6 +125,7 @@ void Instance::begin_sync()
   shading_passes.sync();
   main_view.sync();
   world.sync();
+  hiz.sync();
 
   lookdev.sync_background();
   lookdev.sync_overlay();
diff --git a/source/blender/draw/engines/eevee/eevee_instance.hh b/source/blender/draw/engines/eevee/eevee_instance.hh
index 22a5ad1f57a..24c1fae5515 100644
--- a/source/blender/draw/engines/eevee/eevee_instance.hh
+++ b/source/blender/draw/engines/eevee/eevee_instance.hh
@@ -29,6 +29,7 @@
 #include "DRW_render.h"
 
 #include "eevee_film.hh"
+#include "eevee_hizbuffer.hh"
 #include "eevee_id_map.hh"
 #include "eevee_light.hh"
 #include "eevee_lightprobe.hh"
@@ -69,6 +70,7 @@ class Instance {
   MotionBlurModule motion_blur;
   LightModule lights;
   LightProbeModule lightprobes;
+  HiZBufferModule hiz;
   /* TODO(fclem) Move it to scene layer data. */
   ShadowModule shadows;
   SubsurfaceModule subsurface;
@@ -110,6 +112,7 @@ class Instance {
         motion_blur(*this),
         lights(*this),
         lightprobes(*this),
+        hiz(*this),
         shadows(*this),
         subsurface(*this),
         sync(*this),
diff --git a/source/blender/draw/engines/eevee/eevee_shader.cc b/source/blender/draw/engines/eevee/eevee_shader.cc
index 654a01cac80..8c8262f5893 100644
--- a/source/blender/draw/engines/eevee/eevee_shader.cc
+++ b/source/blender/draw/engines/eevee/eevee_shader.cc
@@ -54,6 +54,8 @@ extern char datatoc_eevee_deferred_holdout_frag_glsl[];
 extern char datatoc_eevee_deferred_transparent_frag_glsl[];
 extern char datatoc_eevee_deferred_volume_frag_glsl[];
 extern char datatoc_eevee_depth_clear_frag_glsl[];
+extern char datatoc_eevee_hiz_copy_frag_glsl[];
+extern char datatoc_eevee_hiz_downsample_frag_glsl[];
 extern char datatoc_eevee_depth_of_field_accumulator_lib_glsl[];
 extern char datatoc_eevee_depth_of_field_bokeh_lut_frag_glsl[];
 extern char datatoc_eevee_depth_of_field_downsample_frag_glsl[];
@@ -214,6 +216,8 @@ ShaderModule::ShaderModule()
   SHADER_FULLSCREEN(DEFERRED_EVAL_VOLUME, eevee_deferred_volume_frag);
   SHADER(DEFERRED_MESH, eevee_surface_mesh_vert, nullptr, eevee_surface_deferred_frag, nullptr);
   SHADER(DEFERRED_VOLUME, eevee_volume_vert, nullptr, eevee_volume_deferred_frag, nullptr);
+  SHADER_FULLSCREEN(HIZ_COPY, eevee_hiz_copy_frag);
+  SHADER_FULLSCREEN(HIZ_DOWNSAMPLE, eevee_hiz_downsample_frag);
   SHADER_FULLSCREEN(DOF_BOKEH_LUT, eevee_depth_of_field_bokeh_lut_frag);
   SHADER_FULLSCREEN(DOF_FILTER, eevee_depth_of_field_filter_frag);
   SHADER_FULLSCREEN_DEFINES(DOF_GATHER_BACKGROUND_LUT,
diff --git a/source/blender/draw/engines/eevee/eevee_shader.hh b/source/blender/draw/engines/eevee/eevee_shader.hh
index 792248540f7..4d0dc93d616 100644
--- a/source/blender/draw/engines/eevee/eevee_shader.hh
+++ b/source/blender/draw/engines/eevee/eevee_shader.hh
@@ -77,6 +77,9 @@ enum eShaderType {
   FILM_RESOLVE,
   FILM_RESOLVE_DEPTH,
 
+  HIZ_COPY,
+  HIZ_DOWNSAMPLE,
+
   LIGHTPROBE_DISPLAY_CUBEMAP,
   LIGHTPROBE_DISPLAY_IRRADIANCE,
 
diff --git a/source/blender/draw/engines/eevee/eevee_shader_shared.hh b/source/blender/draw/engines/eevee/eevee_shader_shared.hh
index d566212c49b..05e4ded136e 100644
--- a/source/blender/draw/engines/eevee/eevee_shader_shared.hh
+++ b/source/blender/draw/engines/eevee/eevee_shader_shared.hh
@@ -613,6 +613,20 @@ BLI_STATIC_ASSERT_ALIGN(LightProbeInfoData, 16)
 /** \} */
 
 /* -------------------------------------------------------------------- */
+/** \name Hierarchical-Z Buffer
+ * \{ */
+
+struct HiZData {
+  /** Scale factor to remove HiZBuffer padding. */
+  vec2 uv_scale;
+  int _pad0;
+  int _pad1;
+};
+BLI_STATIC_ASSERT_ALIGN(HiZData, 16)
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
 /** \name Subsurface
  * \{ */
 
@@ -699,6 +713,7 @@ using CubemapDataBuf = StructArrayBuffer<CubemapData, CULLING_ITEM_BATCH>;
 using CullingDataBuf = StructBuffer<CullingData>;
 using DepthOfFieldDataBuf = StructBuffer<DepthOfFieldData>;
 using GridDataBuf = StructArrayBuffer<GridData, GRID_MAX>;
+using HiZDataBuf = StructBuffer<HiZData>;
 using LightDataBuf = StructArrayBuffer<LightData, CULLING_ITEM_BATCH>;
 using LightProbeFilterDataBuf = StructBuffer<LightProbeFilterData>;
 using LightProbeInfoDataBuf = StructBuffer<LightProbeInfoData>;
diff --git a/source/blender/draw/engines/eevee/eevee_shading.cc b/source/blender/draw/engines/eevee/eevee_shading.cc
index 948ff9ba524..16c03731dee 100644
--- a/source/blender/draw/engines/eevee/eevee_shading.cc
+++ b/source/blender/draw/engines/eevee/eevee_shading.cc
@@ -273,40 +273,57 @@ void DeferredLayer::volume_add(Object *ob)
   DRW_shgroup_call(grp, DRW_cache_cube_get(), ob);
 }
 
-void DeferredLayer::render(GBuffer &gbuffer, GPUFrameBuffer *view_fb)
+void DeferredLayer::render(GBuffer &gbuffer, HiZBuffer &hiz, GPUFrameBuffer *view_fb)
 {
+  DeferredPass &deferred_pass = inst_.shading_passes.deferred;
+
   const bool no_surfaces = DRW_pass_is_empty(gbuffer_ps_);
   const bool no_volumes = DRW_pass_is_empty(volume_ps_);
   if (no_surfaces && no_volumes) {
     return;
   }
+  /* TODO(fclem): detect these cases. */
+  const bool use_refraction = true;
+  const bool use_glossy = true;
+  const bool use_ao = false;
+
+  gbuffer.prepare((eClosureBits)0xFFFFFFFFu);
+  hiz.prepare(gbuffer.depth_tx);
 
-  gbuffer.bind((eClosureBits)0xFFFFFFFFu);
+  update_pass_inputs(gbuffer, hiz);
+
+  if (use_refraction) {
+    /* TODO(fclem) Only update if needed.
+     * i.e: No need when SSR from previous layer has already updated hiz. */
+    hiz.update(gbuffer.depth_tx);
+  }
+
+  gbuffer.bind();
 
   if (!no_surfaces) {
     DRW_draw_pass(prepass_ps_);
+
+    /* TODO(fclem): Ambient Occlusion texture node. */
+    /* NOTE(fclem): Needs a separate hiz if used at the same time as refraction. */
+    if (use_ao) {
+      hiz.update(gbuffer.depth_tx);
+      gbuffer.bind();
+    }
+
     DRW_draw_pass(gbuffer_ps_);
   }
 
-  DeferredPass &deferred_pass = inst_.shading_passes.deferred;
-  deferred_pass.input_combined_tx = gbuffer.combined_tx;
-  deferred_pass.input_emission_data_tx_ = gbuffer.emission_tx;
-  deferred_pass.input_transmit_color_tx_ = gbuffer.transmit_color_tx;
-  deferred_pass.input_transmit_normal_tx_ = gbuffer.transmit_normal_tx;
-  deferred_pass.input_transmit_data_tx_ = gbuffer.transmit_data_tx;
-  deferred_pass.input_reflect_color_tx_ = gbuffer.reflect_color_tx;
-  deferred_pass.input_reflect_normal_tx_ = gbuffer.reflect_normal_tx;
-  deferred_pass.input_diffuse_tx_ = gbuffer.diffuse_tx;
-  deferred_pass.input_transparency_data_tx_ = gbuffer.transparency_tx;
-  deferred_pass.input_volume_data_tx_ = gbuffer.volume_tx;
-  deferred_pass.input_depth_tx_ = gbuffer.depth_copy_tx;
-
-  if (!no_volumes) {
-    gbuffer.copy_depth_behind();
-    deferred_pass.input_depth_behind_tx_ = gbuffer.depth_behind_tx;
+  if (use_refraction) {
+    // if (inst_.raytracing.enabled()) {
+    // DRW_draw_pass(deferred_pass.trace_refraction_ps_);
+    // }
+    // DRW_draw_pass(deferred_pass.eval_refraction_ps_);
   }
 
   if (!no_volumes) {
+    // gbuffer.copy_depth_behind();
+    // deferred_pass.input_depth_behind_tx_ = gbuffer.depth_behind_tx;
+
     for (auto index : inst_.lights.index_range()) {
       inst_.lights.bind_batch(index);
 
@@ -315,7 +332,7 @@ void DeferredLayer::render(GBuffer &gbuffer, GPUFrameBuffer *view_fb)
     }
   }
 
-  gbuffer.copy_depth();
+  hiz.update(gbuffer.depth_tx);
 
   if (true) {
     gbuffer.bind_holdout();
@@ -348,6 +365,26 @@ void DeferredLayer::render(GBuffer &gbuffer, GPUFrameBuffer *view_fb)
     GPU_framebuffer_bind(view_fb);
     DRW_draw_pass(deferred_pass.eval_subsurface_ps_);
   }
+
+  // if (use_glossy && inst_.raytracing.enabled()) {
+  //   inst_.raytracing.trace_reflection(gbuffer);
+  // }
+}
+
+void DeferredLayer::update_pass_inputs(GBuffer &gbuffer, HiZBuffer &hiz)
+{
+  DeferredPass &deferred_pass = inst_.shading_passes.deferred;
+  deferred_pass.input_combined_tx_ = gbuffer.combined_tx;
+  deferred_pass.input_emission_data_tx_ = gbuffer.emission_tx;
+  deferred_pass.input_transmit_color_tx_ = gbuffer.transmit_color_tx;
+  deferred_pass.input_transmit_normal_tx_ = gbuffer.transmit_normal_tx;
+  deferred_pass.input_transmit_data_tx_ = gbuffer.transmit_data_tx;
+  deferred_pass.input_reflect_color_tx_ = gbuffer.reflect_color_tx;
+  deferred_pass.input_reflect_normal_tx_ = gbuffer.reflect_normal_tx;
+  deferred_pass.input_diffuse_tx_ = gbuffer.diffuse_tx;
+  deferred_pass.input_transparency_data_tx_ = gbuffer.transparency_tx;
+  deferred_pass.input_volume_data_tx_ = gbuffer.volume_tx;
+  deferred_pass.input_hiz_tx_ = hiz.texture_get();
 }
 
 /** \} */
@@ -399,7 +436,7 @@ void DeferredPass::sync(void)
         grp, "reflect_color_tx", &input_reflect_color_tx_, no_interp);
     DRW_shgroup_uniform_texture_ref_ex(
         grp, "reflect_normal_tx", &input_reflect_normal_tx_, no_interp);
-    DRW_shgroup_uniform_texture_ref(grp, "depth_tx", &input_depth_tx_);
+    DRW_shgroup_uniform_texture_ref(grp, "hiz_tx", &input_hiz_tx_);
     DRW_shgroup_uniform_texture_ref(
         grp, "sss_transmittance_tx", inst_.subsurface.transmittance_ref_get());
     DRW_shgroup_stencil_set(
@@ -413,7 +450,8 @@ void DeferredPass::sync(void)
     DRWShadingGroup *grp = DRW_shgroup_create(sh, eval_subsurface_ps_);
     DRW_shgroup_uniform_block(grp, "subsurface_block", inst_.subsurface.ubo_get());
     DRW_shgroup_uniform_block(grp, "sampling_block", inst_.sampling.ubo_get());
-    DRW_shgroup_uniform_texture_ref(grp, "depth_tx", &input_depth_tx_);
+    DRW_shgroup_uniform_block(grp, "hiz_block", inst_.hiz.ubo_get());
+    DRW_shgroup_uniform_texture_ref(grp, "hiz_tx", &input_hiz_tx_);
     DRW_shgroup_uniform_texture_ref_ex(grp, "radiance_tx", &input_diffuse_tx_, no_interp);
     DRW_shgroup_uniform_texture_ref_ex(
         grp, "transmit_color_tx", &input_transmit_color_tx_, no_interp);
@@ -438,7 +476,7 @@ void DeferredPass::sync(void)
     DRW_shgroup_uniform_texture_ref_ex(
         grp, "transparency_data_tx", &input_transparency_data_tx_, no_interp);
     DRW_shgroup_uniform_texture_ref_ex(grp, "volume_data_tx", &input_volume_data_tx_, no_interp);
-    DRW_shgroup_uniform_texture_ref(grp, "depth_tx", &input_depth_tx_);
+    DRW_shgroup_uniform_texture_ref(grp, "hiz_tx", &input_hiz_tx_);
     DRW_shgroup_stencil_set(grp, 0x0, 0x0, CLOSURE_VOLUME);
     DRW_shgroup_call_procedural_triangles(grp, nullptr, 1);
   }
@@ -449,7 +487,7 @@ void DeferredPass::sync(void)
     DRWShadingGroup *grp = DRW_shgroup_create(sh, eval_transparency_ps_);
     DRW_shgroup_uniform_texture_ref(grp, "transparency_data_tx", &input_transparency_data_tx_);
     DRW_shgroup_uniform_texture_ref_ex(grp, "volume_data_tx", &input_volume_data_tx_, no_interp);
-    DRW_shgroup_uniform_texture_ref(grp, "depth_tx", &input_depth_tx_);
+    DRW_shgroup_uniform_texture_ref(grp, "hiz_tx", &input_hiz_tx_);
     DRW_shgroup_stencil_set(grp, 0x0, 0x0, CLOSURE_TRANSPARENCY);
     DRW_shgroup_call_procedural_triangles(grp, nullptr, 1);
   }
@@ -458,7 +496,7 @@ void DeferredPass::sync(void)
     eval_holdout_ps_ = DRW_pass_create("DeferredHoldout", state);
     GPUShader *sh = inst_.shaders.static_shader_get(DEFERRED_EVAL_HOLDOUT);
     DRWShadingGroup *grp = DRW_shgroup_create(sh, eval_volume_homogeneous_ps_);
-    DRW_shgroup_uniform_texture_ref(grp, "combined_tx", &input_combined_tx);
+    DRW_shgroup_uniform_texture_ref(grp, "combined_tx", &input_combined_tx_);
     DRW_shgroup_uniform_texture_ref(grp, "transparency_data_tx", &input_transparency_data_tx_);
     DRW_shgroup_stencil_set(grp, 0x0, 0x0, CLOSURE_TRANSPARENCY);
     DRW_shgroup_call_procedural_triangles(grp, nullptr, 1);
@@ -490,11 +528,11 @@ void DeferredPass::volume_add(Object *ob)
   volumetric_layer_.volume_add(ob);
 }
 
-void DeferredPass::render(GBuffer &gbuffer, GPUFrameBuffer *view_fb)
+void DeferredPass::render(GBuffer &gbuffer, HiZBuffer &hiz, GPUFrameBuffer *view_fb)
 {
-  opaque_layer_.render(gbuffer, view_fb);
-  refraction_layer_.render(gbuffer, view_fb);
-  volumetric_layer_.render(gbuffer, view_fb);
+  opaque_layer_.render(gbuffer, hiz, view_fb);
+  refraction_layer_.render(gbuffer, hiz, view_fb);
+  volumetric_layer_.render(gbuffer, hiz, view_fb);
 
   gbuffer.render_end();
 }
diff --git a/source/blender/draw/engines/eevee/eevee_shading.hh b/source/blender/draw/engines/eevee/eevee_shading.hh
index 691bce3e97e..e042dea1dc6 100644
--- a/source/blender/draw/engines/eevee/eevee_shading.hh
+++ b/source/blender/draw/engines/eevee/eevee_shading.hh
@@ -140,10 +140,8 @@ struct GBuffer {
   Framebuffer holdout_fb = Framebuffer("Holdout");
 
   Texture depth_behind_tx = Texture("DepthBehind");
-  Texture depth_copy_tx = Texture("DepthCopy");
 
   Framebuffer depth_behind_fb = Framebuffer("DepthCopy");
-  Framebuffer depth_copy_fb = Framebuffer("DepthCopy");
 
   /* Owner of this GBuffer. Used to query temp textures. */
   void *owner;
@@ -170,10 +168,9 @@ struct GBuffer {
     holdout_tx.sync_tmp();
     diffuse_tx.sync_tmp();
     depth_behind_tx.sync_tmp();
-    depth_copy_tx.sync_tmp();
   }
 
-  void bind(eClosureBits closures_used)
+  void prepare(eClosureBits closures_used)
   {
     ivec2 extent = {GPU_texture_width(depth_tx), GPU_texture_height(depth_tx)};
 
@@ -214,7 +211,6 @@ struct GBuffer {
 
     holdout_tx.acquire_tmp(UNPACK2(extent), GPU_R11F_G11F_B10F, owner);
     depth_behind_tx.acquire_tmp(UNPACK2(extent), GPU_DEPTH24_STENCIL8, owner);
-    depth_copy_tx.acquire_tmp(UNPACK2(extent), GPU_DEPTH24_STENCIL8, owner);
 
     /* Layer attachement also works with cubemap. */
     gbuffer_fb.ensure(GPU_ATTACHMENT_TEXTURE_LAYER(depth_tx, layer),
@@ -226,6 +222,10 @@ struct GBuffer {
                       GPU_ATTACHMENT_TEXTURE(volume_tx),
                       GPU_ATTACHMENT_TEXTURE(emission_tx),
                       GPU_ATTACHMENT_TEXTURE(transparency_tx));
+  }
+
+  void bind(void)
+  {
     GPU_framebuffer_bind(gbuffer_fb);
     GPU_framebuffer_clear_stencil(gbuffer_fb, 0x0);
   }
@@ -262,14 +262,6 @@ struct GBuffer {
     GPU_framebuffer_blit(gbuffer_fb, 0, depth_behind_fb, 0, GPU_DEPTH_BIT);
   }
 
-  void copy_depth(void)
-  {
-    depth_copy_fb.ensure(GPU_ATTACHMENT_TEXTURE(depth_copy_tx));
-    GPU_framebuffer_bind(depth_copy_fb);
-
-    GPU_framebuffer_blit(gbuffer_fb, 0, depth_copy_fb, 0, GPU_DEPTH_BIT);
-  }
-
   void clear_radiance(void)
   {
     radiance_clear_fb.ensure(GPU_ATTACHMENT_NONE, GPU_ATTACHMENT_TEXTURE(diffuse_tx));
@@ -292,7 +284,6 @@ struct GBuffer {
     holdout_tx.release_tmp();
     diffuse_tx.release_tmp();
     depth_behind_tx.release_tmp();
-    depth_copy_tx.release_tmp();
   }
 };
 
@@ -318,7 +309,10 @@ class DeferredLayer {
   DRWShadingGroup *material_add(::Material *blender_mat, GPUMaterial *gpumat);
   DRWShadingGroup *prepass_add(::Material *blender_mat, GPUMaterial *gpumat);
   void volume_add(Object *ob);
-  void render(GBuffer &gbuffer, GPUFrameBuffer *view_fb);
+  void render(GBuffer &gbuffer, HiZBuffer &hiz, GPUFrameBuffer *view_fb);
+
+ private:
+  void update_pass_inputs(GBuffer &gbuffer, HiZBuffer &hiz);
 };
 
 class DeferredPass {
@@ -341,16 +335,16 @@ class DeferredPass {
   DRWPass *eval_volume_homogeneous_ps_ = nullptr;
 
   /* References only. */
-  GPUTexture *input_combined_tx = nullptr;
+  GPUTexture *input_combined_tx_ = nullptr;
   GPUTexture *input_depth_behind_tx_ = nullptr;
-  GPUTexture *input_depth_tx_ = nullptr;
+  GPUTexture *input_diffuse_tx_ = nullptr;
   GPUTexture *input_emission_data_tx_ = nullptr;
-  GPUTexture *input_transmit_color_tx_ = nullptr;
-  GPUTexture *input_transmit_normal_tx_ = nullptr;
-  GPUTexture *input_transmit_data_tx_ = nullptr;
+  GPUTexture *input_hiz_tx_ = nullptr;
   GPUTexture *input_reflect_color_tx_ = nullptr;
   GPUTexture *input_reflect_normal_tx_ = nullptr;
-  GPUTexture *input_diffuse_tx_ = nullptr;
+  GPUTexture *input_transmit_color_tx_ = nullptr;
+  GPUTexture *input_transmit_data_tx_ = nullptr;
+  GPUTexture *input_transmit_normal_tx_ = nullptr;
   GPUTexture *input_transparency_data_tx_ = nullptr;
   GPUTexture *input_volume_data_tx_ = nullptr;
   // GPUTexture *input_volume_radiance_tx_ = nullptr;
@@ -364,7 +358,7 @@ class DeferredPass {
   DRWShadingGroup *material_add(::Material *material, GPUMaterial *gpumat);
   DRWShadingGroup *prepass_add(::Material *material, GPUMaterial *gpumat);
   void volume_add(Object *ob);
-  void render(GBuffer &gbuffer, GPUFrameBuffer *view_fb);
+  void render(GBuffer &gbuffer, HiZBuffer &hiz, GPUFrameBuffer *view_fb);
 };
 
 /** \} */
diff --git a/source/blender/draw/engines/eevee/eevee_view.cc b/source/blender/draw/engines/eevee/eevee_view.cc
index 72e2baa6815..ef2cbf499ef 100644
--- a/source/blender/draw/engines/eevee/eevee_view.cc
+++ b/source/blender/draw/engines/eevee/eevee_view.cc
@@ -134,7 +134,7 @@ void ShadingView::render(void)
     inst_.shading_passes.background.render();
   }
 
-  inst_.shading_passes.deferred.render(gbuffer_, view_fb_);
+  inst_.shading_passes.deferred.render(gbuffer_, hiz_, view_fb_);
 
   inst_.lightprobes.draw_cache_display();
 
@@ -248,7 +248,7 @@ void LightProbeView::render(void)
   if (!is_only_background_) {
     GPU_framebuffer_clear_depth(view_fb_, 1.0f);
 
-    inst_.shading_passes.deferred.render(gbuffer_, view_fb_);
+    inst_.shading_passes.deferred.render(gbuffer_, hiz_, view_fb_);
     inst_.shading_passes.forward.render();
   }
   DRW_stats_group_end();
diff --git a/source/blender/draw/engines/eevee/eevee_view.hh b/source/blender/draw/engines/eevee/eevee_view.hh
index 901f6c1036f..5e3afead4c0 100644
--- a/source/blender/draw/engines/eevee/eevee_view.hh
+++ b/source/blender/draw/engines/eevee/eevee_view.hh
@@ -37,6 +37,7 @@
 #include "DRW_render.h"
 
 #include "eevee_depth_of_field.hh"
+#include "eevee_hizbuffer.hh"
 #include "eevee_motion_blur.hh"
 #include "eevee_renderpasses.hh"
 #include "eevee_shader.hh"
@@ -56,7 +57,7 @@ class Instance;
 class ShadingView {
  private:
   Instance &inst_;
-  /** Static srting pointer. Used as debug name and as UUID for texture pool. */
+  /** Static string pointer. Used as debug name and as UUID for texture pool. */
   const char *name_;
   /** Matrix to apply to the viewmat. */
   const float (*face_matrix_)[4];
@@ -66,7 +67,10 @@ class ShadingView {
   MotionBlur mb_;
   Velocity velocity_;
 
+  /** GBuffer for deferred passes. */
   GBuffer gbuffer_;
+  /** HiZBuffer for screenspace effects. */
+  HiZBuffer hiz_;
 
   /** Owned resources. */
   eevee::Framebuffer view_fb_;
@@ -96,7 +100,8 @@ class ShadingView {
         face_matrix_(face_matrix),
         dof_(inst, name),
         mb_(inst, name),
-        velocity_(inst, name){};
+        velocity_(inst, name),
+        hiz_(inst){};
 
   ~ShadingView(){};
 
@@ -129,6 +134,8 @@ class LightProbeView {
   const float (*face_matrix_)[4];
   /** GBuffer for deferred passes. */
   GBuffer gbuffer_;
+  /** HiZBuffer for screenspace effects. */
+  HiZBuffer hiz_;
   /** Owned resources. */
   Framebuffer view_fb_;
   /** DRWView of this face. */
@@ -141,7 +148,7 @@ class LightProbeView {
 
  public:
   LightProbeView(Instance &inst, const char *name, const float (*face_matrix)[4], int layer_)
-      : inst_(inst), name_(name), face_matrix_(face_matrix), layer_(layer_){};
+      : inst_(inst), name_(name), face_matrix_(face_matrix), hiz_(inst), layer_(layer_){};
 
   ~LightProbeView(){};
 
diff --git a/source/blender/draw/engines/eevee/shaders/eevee_deferred_direct_frag.glsl b/source/blender/draw/engines/eevee/shaders/eevee_deferred_direct_frag.glsl
index 9335970ba4d..dd4d0ba4f20 100644
--- a/source/blender/draw/engines/eevee/shaders/eevee_deferred_direct_frag.glsl
+++ b/source/blender/draw/engines/eevee/shaders/eevee_deferred_direct_frag.glsl
@@ -46,7 +46,7 @@ layout(std140) uniform lightprobes_info_block
   LightProbeInfoData probes_info;
 };
 
-uniform sampler2D depth_tx;
+uniform sampler2D hiz_tx;
 uniform sampler2D emission_data_tx;
 uniform sampler2D transmit_color_tx;
 uniform sampler2D transmit_normal_tx;
@@ -84,7 +84,7 @@ vec3 lightprobe_cubemap_eval(vec3 P, vec3 R, float roughness, float random_thres
 
 void main(void)
 {
-  float gbuffer_depth = texture(depth_tx, uvcoordsvar.xy).r;
+  float gbuffer_depth = texelFetch(hiz_tx, ivec2(gl_FragCoord.xy), 0).r;
   vec3 vP = get_view_space_from_depth(uvcoordsvar.xy, gbuffer_depth);
   vec3 P = point_view_to_world(vP);
   vec3 V = cameraVec(P);
diff --git a/source/blender/draw/engines/eevee/shaders/eevee_hiz_copy_frag.glsl b/source/blender/draw/engines/eevee/shaders/eevee_hiz_copy_frag.glsl
new file mode 100644
index 00000000000..f0ee9f515c9
--- /dev/null
+++ b/source/blender/draw/engines/eevee/shaders/eevee_hiz_copy_frag.glsl
@@ -0,0 +1,17 @@
+/**
+ * Copy input depth texture to lower left corner of the destination, filling any padding with
+ * clamped texture extrapolation.
+ */
+
+#pragma BLENDER_REQUIRE(common_view_lib.glsl)
+
+uniform sampler2D depth_tx;
+
+layout(location = 0) out float out_depth;
+
+void main()
+{
+  vec2 uv = gl_FragCoord.xy / vec2(textureSize(depth_tx, 0).xy);
+
+  out_depth = texture(depth_tx, uv).r;
+}
diff --git a/source/blender/draw/engines/eevee/shaders/eevee_hiz_downsample_frag.glsl b/source/blender/draw/engines/eevee/shaders/eevee_hiz_downsample_frag.glsl
new file mode 100644
index 00000000000..9a095d960b2
--- /dev/null
+++ b/source/blender/draw/engines/eevee/shaders/eevee_hiz_downsample_frag.glsl
@@ -0,0 +1,40 @@
+/**
+ * Shader that down-sample depth buffer, creating a Hierarchical-Z buffer.
+ * Saves max value of each 2x2 texel in the mipmap above the one we are rendering to.
+ * Adapted from http://rastergrid.com/blog/2010/10/hierarchical-z-map-based-occlusion-culling/
+ *
+ * Major simplification has been made since we pad the buffer to always be bigger than input to
+ * avoid mipmapping misalignement.
+ */
+
+#pragma BLENDER_REQUIRE(common_math_lib.glsl)
+
+uniform sampler2D depth_tx;
+
+uniform vec2 texel_size;
+
+layout(location = 0) out float out_depth;
+
+#ifndef GPU_ARB_texture_gather
+vec4 texGather(sampler2D tex, vec2 uv)
+{
+  vec4 ofs = vec2(0.5, 0.5, -0.5, -0.5) * texel_size.xyxy;
+  return vec4(texture(tex, uv + ofs.zw).r,
+              texture(tex, uv + ofs.zy).r,
+              texture(tex, uv + ofs.xw).r,
+              texture(tex, uv + ofs.xy).r);
+}
+#else
+#  define texGather(a, b) textureGather(a, b)
+#endif
+
+void main()
+{
+  /* NOTE(@fclem): textureSize() does not work the same on all implementations
+   * when changing the min and max texture levels. Use uniform instead (see T87801). */
+  vec2 uv = gl_FragCoord.xy * texel_size;
+
+  vec4 samp = texGather(depth_tx, uv);
+
+  out_depth = max_v4(samp);
+}
diff --git a/source/blender/draw/engines/eevee/shaders/eevee_subsurface_eval_frag.glsl b/source/blender/draw/engines/eevee/shaders/eevee_subsurface_eval_frag.glsl
index 50ec88b1990..e24c2dccdbf 100644
--- a/source/blender/draw/engines/eevee/shaders/eevee_subsurface_eval_frag.glsl
+++ b/source/blender/draw/engines/eevee/shaders/eevee_subsurface_eval_frag.glsl
@@ -23,7 +23,12 @@ layout(std140) uniform subsurface_block
   SubsurfaceData sss;
 };
 
-uniform sampler2D depth_tx;
+layout(std140) uniform hiz_block
+{
+  HiZData hiz;
+};
+
+uniform sampler2D hiz_tx;
 uniform sampler2D radiance_tx;
 uniform sampler2D transmit_color_tx;
 uniform sampler2D transmit_normal_tx;
@@ -63,7 +68,8 @@ void main(void)
 {
   vec2 center_uv = uvcoordsvar.xy;
 
-  vec3 vP = get_view_space_from_depth(center_uv, texture(depth_tx, center_uv).r);
+  float gbuffer_depth = texelFetch(hiz_tx, ivec2(gl_FragCoord.xy), 0).r;
+  vec3 vP = get_view_space_from_depth(center_uv, gbuffer_depth);
   vec4 tra_col_in = texture(transmit_color_tx, center_uv);
   vec4 tra_nor_in = texture(transmit_normal_tx, center_uv);
   vec4 tra_dat_in = texture(transmit_data_tx, center_uv);
@@ -111,7 +117,7 @@ void main(void)
     vec2 sample_uv = center_uv + sample_space * sss.samples[i].xy;
     float pdf = sss.samples[i].z;
 
-    float sample_depth = texture(depth_tx, sample_uv).r;
+    float sample_depth = texture(hiz_tx, sample_uv * hiz.uv_scale).r;
     vec3 sample_vP = get_view_space_from_depth(sample_uv, sample_depth);
 
     vec4 sample_data = texture(radiance_tx, sample_uv);