1 files changed, 88 insertions, 0 deletions
diff --git a/source/blender/draw/engines/eevee_next/eevee_hizbuffer.hh b/source/blender/draw/engines/eevee_next/eevee_hizbuffer.hh
new file mode 100644
index 00000000000..8b8e4de55b1
--- /dev/null
+++ b/source/blender/draw/engines/eevee_next/eevee_hizbuffer.hh
@@ -0,0 +1,88 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ * 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_;
+
+  /** The texture containing the hiz mip chain. */
+  Texture hiz_tx_ = {"hiz_tx_"};
+  /**
+   * Atomic counter counting the number of tile that have finished down-sampling.
+   * The last one will process the last few mip level.
+   */
+  draw::StorageBuffer<uint4, true> atomic_tile_counter_ = {"atomic_tile_counter"};
+  /** Single pass recursive downsample. */
+  PassSimple hiz_update_ps_ = {"HizUpdate"};
+  /** Debug pass. */
+  PassSimple debug_draw_ps_ = {"HizUpdate.Debug"};
+  /** Dirty flag to check if the update is necessary. */
+  bool is_dirty_ = true;
+
+  HiZDataBuf data_;
+
+ public:
+  HiZBuffer(Instance &inst) : inst_(inst)
+  {
+    atomic_tile_counter_.clear_to_zero();
+  };
+
+  void sync();
+
+  /**
+   * Tag the buffer for update if needed.
+   */
+  void set_dirty()
+  {
+    is_dirty_ = true;
+  }
+
+  /**
+   * Update the content of the HiZ buffer with the depth render target.
+   * Noop if the buffer has not been tagged as dirty.
+   * Should be called before each passes that needs to read the hiz buffer.
+   */
+  void update();
+
+  void debug_draw(View &view, GPUFrameBuffer *view_fb);
+
+  void bind_resources(DRWShadingGroup *grp)
+  {
+    DRW_shgroup_uniform_texture_ref(grp, "hiz_tx", &hiz_tx_);
+    DRW_shgroup_uniform_block_ref(grp, "hiz_buf", &data_);
+  }
+
+  /* TODO(fclem): Hardcoded bind slots. */
+  template<typename T> void bind_resources(draw::detail::PassBase<T> *pass)
+  {
+    pass->bind_texture("hiz_tx", &hiz_tx_);
+    pass->bind_ubo("hiz_buf", &data_);
+  }
+};
+
+/** \} */
+
+}  // namespace blender::eevee