ExtractSceneBuffer.hpp

#pragma once
#include <halp/buffer.hpp>
#include <halp/controls.hpp>
#include <halp/meta.hpp>
 
#include <ossia/dataflow/geometry_port.hpp>
 
#include <Gfx/Graph/GpuResourceRegistry.hpp>
 
#include <cstdint>
 
class QRhiResourceUpdateBatch;
 
namespace score::gfx
{
class RenderList;
struct Edge;
}
 
namespace Threedim
{
 
// Scene-level buffer extractor: takes a scene_spec, picks one of the GPU arena
// slots stamped on the scene's components, and republishes the backing
// {QRhiBuffer*, byte_offset, byte_size} triple on a halp::gpu_buffer outlet.
//
// Unlike Threedim::ExtractBuffer2, which extracts from a flattened geometry's
// aux list downstream of a ScenePreprocessor, this works directly on a raw
// scene_spec -- for a compute shader that wants a producer's Raw arena slot
// without a preprocessor flatten, or a pipeline that has no preprocessor at all.
//
// Source resolution uses each component's `raw_slot`:
//   Environment  scene.state->environment.raw_slot
//   Camera(N)    (*scene.state->cameras)[N]->raw_slot
//   Material(N)  (*scene.state->materials)[N]->raw_slot
//
// The registry's isLive() check guards every read; a stale ref clears the outlet
// rather than handing a dangling QRhiBuffer* downstream.
//
// Lights are not exposed because the light tree is not a flat scene_state.lights
// vector -- lights live as scene_payload children. Extract them downstream of a
// ScenePreprocessor with ExtractBuffer2("scene_lights").
class ExtractSceneBuffer
{
public:
  halp_meta(name, "Extract Scene Buffer")
  halp_meta(category, "Visuals/3D/Scene")
  halp_meta(c_name, "extract_scene_buffer")
  halp_meta(description, "Expose a scene environment, camera or material GPU buffer without flattening the scene.")
  halp_meta(authors, "ossia team")
  halp_meta(
      manual_url,
      "https://ossia.io/score-docs/processes/extract-scene-buffer.html")
  halp_meta(uuid, "5f2b8e1c-4a7d-4e9b-b0f1-3c6e8d2a5b74")
 
  enum Kind
  {
    Environment,
    Camera,
    Material
  };
 
  struct ins
  {
    struct
    {
      halp_meta(name, "Scene In");
      ossia::scene_spec scene;
      uint8_t dirty{0};
    } scene_in;
 
    struct : halp::combobox_t<"Kind", Kind>
    {
      struct range
      {
        std::string_view values[3]{"Environment", "Camera", "Material"};
        int init{0};
      };
    } kind;
 
    // Index inside scene.state->cameras / ->materials. Ignored when
    // Kind == Environment (the environment is a singleton on scene_state).
    halp::spinbox_i32<"Index", halp::irange{0, 1024, 0}> index;
  } inputs;
 
  struct outs
  {
    halp::gpu_buffer_output<"Buffer"> buffer;
  } outputs;
 
  // Execution-thread tick. No heavy work here — just snapshot the
  // current scene ref + control values. Slot resolution needs the
  // registry (render thread) so it happens in update().
  void operator()();
 
  // Render-thread hooks. update() resolves the slot ref against the
  // renderer's GpuResourceRegistry, validates via isLive(), and
  // publishes the buffer handle + offset + size on the outlet. init()
  // and release() are no-ops for now — the node owns no GPU state.
  void init(score::gfx::RenderList& r, QRhiResourceUpdateBatch& res);
  void update(
      score::gfx::RenderList& r, QRhiResourceUpdateBatch& res,
      score::gfx::Edge* e);
  void release(score::gfx::RenderList& r);
};
 
}