eevee_gbuffer.hh

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/* SPDX-FileCopyrightText: 2023 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

 
#pragma once
 
#include "DRW_render.hh"
#include "GPU_capabilities.hh"
 
#include "GPU_platform.hh"
#include "eevee_material.hh"
#include "eevee_shader_shared.hh"
 
namespace blender::eevee {
 
class Instance;

struct GBuffer {
 public:
  /* TODO(fclem): Use texture from pool once they support texture array and layer views. */
  Texture header_tx = {"GBufferHeader"};
  Texture closure_tx = {"GBufferClosure"};
  Texture normal_tx = {"GBufferNormal"};
 
  /* Expected number of layer written through the framebuffer. */
  const uint header_fb_layer_count = GBUF_HEADER_FB_LAYER_COUNT;
  const uint closure_fb_layer_count = GBUF_CLOSURE_FB_LAYER_COUNT;
  const uint normal_fb_layer_count = GBUF_NORMAL_FB_LAYER_COUNT;
 
 private:
  /* References to optional GBuffer layers that are not always required or written to.
   * These will point to either the dummy textures bellow or to a layer range view of the above
   * textures. In the later case, these layers are written with imageStore instead of being part
   * of the #Framebuffer. */
  GPUTexture *closure_opt_layers_ = nullptr;
  GPUTexture *normal_opt_layers_ = nullptr;
  GPUTexture *header_opt_layers_ = nullptr;
 
  /* Textures used to fulfill the GBuffer optional layers binding when textures do not have enough
   * layers for the optional layers image views. The shader are then expected to never write to
   * them. */
  Texture dummy_header_tx_ = {"GBufferDummyHeader"};
  Texture dummy_closure_tx_ = {"GBufferDummyClosure"};
  Texture dummy_normal_tx_ = {"GBufferDummyNormal"};
 
 public:
  void acquire(int2 extent, int header_count, int data_count, int normal_count)
  {
    /* Always allocate enough layers so that the frame-buffer attachments are always valid. */
    header_count = max_ii(header_fb_layer_count, header_count);
    data_count = max_ii(closure_fb_layer_count, data_count);
    normal_count = max_ii(normal_fb_layer_count, normal_count);
 
    dummy_header_tx_.ensure_2d_array(GPU_R32UI, int2(1), 1, GPU_TEXTURE_USAGE_SHADER_WRITE);
    dummy_closure_tx_.ensure_2d_array(GPU_RGB10_A2, int2(1), 1, GPU_TEXTURE_USAGE_SHADER_WRITE);
    dummy_normal_tx_.ensure_2d_array(GPU_RG16, int2(1), 1, GPU_TEXTURE_USAGE_SHADER_WRITE);
 
    eGPUTextureUsage usage = GPU_TEXTURE_USAGE_SHADER_READ | GPU_TEXTURE_USAGE_SHADER_WRITE |
                             GPU_TEXTURE_USAGE_ATTACHMENT;
    header_tx.ensure_2d_array(GPU_R32UI, extent, header_count, usage);
    closure_tx.ensure_2d_array(GPU_RGB10_A2, extent, data_count, usage);
    normal_tx.ensure_2d_array(GPU_RG16, extent, normal_count, usage);
    /* Ensure layer view for frame-buffer attachment. */
    header_tx.ensure_layer_views();
    closure_tx.ensure_layer_views();
    normal_tx.ensure_layer_views();
    /* Ensure layer view for image store. */
    auto range = [](int layer_count, int fb_layer_count, Texture &tx, Texture &dummy) {
      return (layer_count > fb_layer_count) ?
                 tx.layer_range_view(fb_layer_count, layer_count - fb_layer_count) :
                 dummy;
    };
    header_opt_layers_ = range(header_count, header_fb_layer_count, header_tx, dummy_header_tx_);
    closure_opt_layers_ = range(data_count, closure_fb_layer_count, closure_tx, dummy_closure_tx_);
    normal_opt_layers_ = range(normal_count, normal_fb_layer_count, normal_tx, dummy_normal_tx_);
  }
 
  /* Bind the GBuffer frame-buffer correctly using the correct workarounds. */
  void bind(Framebuffer &gbuffer_fb)
  {
    /* Workaround a Metal bug that is only showing up on ATI/Intel GPUs. */
    if (GPU_type_matches(
            GPU_DEVICE_ATI | GPU_DEVICE_INTEL | GPU_DEVICE_INTEL_UHD, GPU_OS_MAC, GPU_DRIVER_ANY))
    {
      header_tx.clear(uint4(0));
      GPU_framebuffer_bind(gbuffer_fb);
      return;
    }
 
    if (!GPU_stencil_export_support()) {
      /* Clearing custom load-store frame-buffers is invalid,
       * clear the stencil as a regular frame-buffer first. */
      GPU_framebuffer_bind(gbuffer_fb);
      GPU_framebuffer_clear_stencil(gbuffer_fb, 0x0u);
    }
    GPU_framebuffer_bind_ex(
        gbuffer_fb,
        {
            {GPU_LOADACTION_LOAD, GPU_STOREACTION_STORE},       /* Depth. */
            {GPU_LOADACTION_LOAD, GPU_STOREACTION_STORE},       /* Combined. */
            {GPU_LOADACTION_CLEAR, GPU_STOREACTION_STORE, {0}}, /* GBuf Header. */
            {GPU_LOADACTION_DONT_CARE, GPU_STOREACTION_STORE},  /* GBuf Normal. */
            {GPU_LOADACTION_DONT_CARE, GPU_STOREACTION_STORE},  /* GBuf Closure. */
            {GPU_LOADACTION_DONT_CARE, GPU_STOREACTION_STORE},  /* GBuf Closure 2. */
        });
  }
 
  void release()
  {
    /* TODO(fclem): Use texture from pool once they support texture array. */
    // header_tx.release();
    // closure_tx.release();
    // normal_tx.release();
 
    header_opt_layers_ = nullptr;
    closure_opt_layers_ = nullptr;
    normal_opt_layers_ = nullptr;
  }
 
  template<typename PassType> void bind_resources(PassType &pass)
  {
    pass.bind_texture("gbuf_header_tx", &header_tx);
    pass.bind_texture("gbuf_closure_tx", &closure_tx);
    pass.bind_texture("gbuf_normal_tx", &normal_tx);
  }
 
  template<typename PassType> void bind_optional_layers(PassType &pass)
  {
    pass.bind_image(GBUF_NORMAL_SLOT, &normal_opt_layers_);
    pass.bind_image(GBUF_CLOSURE_SLOT, &closure_opt_layers_);
    pass.bind_image(GBUF_HEADER_SLOT, &header_opt_layers_);
  }
};
 
}  // namespace blender::eevee