ExtractBuffer2.hpp

#pragma once
#include <Threedim/GeometryToBufferStrategies.hpp>
 
#include <halp/buffer.hpp>
#include <halp/controls.hpp>
#include <halp/geometry.hpp>
#include <halp/meta.hpp>
 
namespace Threedim
{
// Name-based version of Threedim::ExtractBuffer, which enumerates a fixed list
// of attribute slots and selects one through a combobox. This one takes a Mode
// enum -- Attribute or Buffer -- and a free-form name interpreted per mode.
//
// Mode == Attribute extracts a single per-vertex attribute:
//   * "position" / "normal" / "tangent" / "bitangent" / "texcoord" or
//     "texcoord0".."texcoord7" / "uv" / "color" or "color0".."color3" match
//     against halp::attribute_semantic
//   * "<integer>" is the Nth entry in mesh.attributes[]
//   * anything else is a custom-name lookup in mesh.attributes[].name
//   The output uses the same Direct / Compute / Indexed strategies.
//
// Mode == Buffer extracts a whole raw buffer:
//   * "<integer>" is the Nth entry in mesh.buffers[]
//   * "index" is the buffer mesh.index points at
//   * a name matching mesh.auxiliary[].name, checked first since aux names may
//     shadow attribute names, returns that auxiliary's backing buffer with its
//     byte_offset and byte_size. This is how ScenePreprocessor's per-frame
//     auxiliaries reach a standalone gpu_buffer outlet for consumers that do
//     not want try_bind_from_geometry
//   * anything else looks up an attribute by semantic or custom name and
//     returns the buffer it lives in
//
// The source buffer handle is re-fetched from the mesh on every update(), so an
// upstream that rebuilds its QRhiBuffer is reflected on the next frame.
class ExtractBuffer2
{
public:
  halp_meta(name, "Extract buffer (by name)")
  halp_meta(category, "Visuals/Utilities")
  halp_meta(c_name, "extract_buffer_by_name")
  halp_meta(description, "Extract a named vertex attribute, raw buffer or auxiliary buffer from geometry.")
  halp_meta(
      manual_url, "https://ossia.io/score-docs/processes/extract-buffer.html")
  halp_meta(uuid, "3c9d6c2b-1f04-4f7d-9bc2-a4b1d7c8e5f0")
 
  enum Mode
  {
    Attribute,
    Buffer
  };
 
  struct ins
  {
    struct
    {
      halp_meta(name, "Geometry");
      halp::dynamic_gpu_geometry mesh;
      float transform[16]{};
      bool dirty_mesh = false;
      bool dirty_transform = false;
    } geometry;
 
    halp::combobox_t<"Mode", Mode> mode;
    struct : halp::lineedit<"Name / index", "position">
    {
      halp_meta(symbol, "name")
    } name;
    halp::toggle<"Pad vec3 to vec4"> pad_to_vec4;
  } inputs;
 
  struct
  {
    halp::gpu_buffer_output<"Buffer"> buffer;
  } outputs;
 
  ExtractBuffer2();
 
  void init(score::gfx::RenderList& renderer, QRhiResourceUpdateBatch& res);
  void update(
      score::gfx::RenderList& renderer, QRhiResourceUpdateBatch& res,
      score::gfx::Edge* e);
  void release(score::gfx::RenderList& r);
  void runInitialPasses(
      score::gfx::RenderList& renderer, QRhiCommandBuffer& commands,
      QRhiResourceUpdateBatch*& res, score::gfx::Edge& edge);
  void operator()();
 
private:
  // Resolve the user's name string to an attribute_lookup, taking the
  // active mesh into account. Returns nullopt on miss.
  [[nodiscard]] static std::optional<attribute_lookup>
  resolveAttribute(const halp::dynamic_gpu_geometry& mesh, std::string_view n) noexcept;
 
  // Resolve the user's name string to a (buffer index, byte_offset, byte_size)
  // triple suitable for DirectBufferReferenceStrategy. Returns -1 on miss.
  struct BufferRef
  {
    int buffer_index{-1};
    int64_t byte_offset{};
    int64_t byte_size{};
  };
  [[nodiscard]] static BufferRef
  resolveBuffer(const halp::dynamic_gpu_geometry& mesh, std::string_view n) noexcept;
 
  // (Re)initialise m_strategy based on the current inputs and mesh.
  void initStrategy(score::gfx::RenderList& renderer);
  void updateOutput();
 
  ExtractionStrategyVariant m_strategy;
  Mode m_currentMode{Attribute};
  std::string m_currentName{};
  bool m_currentPadToVec4{false};
};
}