// Distortion warp pass — M2 gate 5.
//
// Full-screen pass over the direct-mode surface (left half = left eye):
// for each panel pixel, evaluate the S3-verified per-channel POLY3 warp
// (EvalDistortion formula) to get three source UVs, sample the eye texture
// once per channel (distortion + lateral CA in one pass), and apply
// display_color_mult. Outside the source [0,1] range samples black
// (border sampler) — matches the grown render-target bounds.
//
// Sampling: linear for the live pipeline (free AA); point mode for the
// gate-A pixel-diff against the S3 generator.

#pragma once

#include <d3d12.h>
#include <wrl/client.h>

#include "calib/hmd_config.h"

namespace sauna {

class WarpPass {
 public:
  bool init(ID3D12Device* dev, DXGI_FORMAT rtFormat, const HmdConfig& cfg);

  // Records the warp for one eye into its half of the output RT (assumed
  // RENDER_TARGET state, full panel width). eyeSrv = shader-visible GPU
  // handle of the eye texture SRV (caller's heap must be set). panelW/H =
  // full output surface size (e.g. 5088x2544). pointSample: gate-A mode.
  // r2Clamp: clamp r^2 at undistort_r2_cutoff (the Monado/mesh behavior the
  // S3 ComputeDistortion dump does NOT show — A/B switch for the eyes-in
  // periphery question; the poly is extrapolation beyond the cutoff).
  void record(ID3D12GraphicsCommandList* list, int eye,
              D3D12_GPU_DESCRIPTOR_HANDLE eyeSrv, uint32_t panelW,
              uint32_t panelH, bool pointSample = false,
              bool colorMult = true, bool r2Clamp = false);

 private:
  Microsoft::WRL::ComPtr<ID3D12RootSignature> rootSig_;
  Microsoft::WRL::ComPtr<ID3D12PipelineState> pso_;
  float consts_[2][20];  // per eye: cx, cy, scale, pad, kr[4], kg[4], kb[4], colorMult[4]
};

}  // namespace sauna