VUYA.hpp

#pragma once
#include <Gfx/Graph/decoders/ColorSpace.hpp>
#include <Gfx/Graph/decoders/GPUVideoDecoder.hpp>
 
extern "C" {
#include <libavformat/avformat.h>
}
 
namespace score::gfx
{
 
struct VUYADecoder : GPUVideoDecoder
{
  static const constexpr auto frag = R"_(#version 450
 
)_" SCORE_GFX_VIDEO_UNIFORMS R"_(
 
layout(binding=3) uniform sampler2D u_tex;
 
layout(location = 0) in vec2 v_texcoord;
layout(location = 0) out vec4 fragColor;
 
%2
 
vec4 processTexture(vec4 tex) {
  vec4 processed = convert_to_rgb(tex);
  { %1 }
  return processed;
}
 
void main()
{
  vec4 vuya = texture(u_tex, v_texcoord);
  float y = vuya.b;
  float u = vuya.g;
  float v = vuya.r;
 
  vec4 rgb = processTexture(vec4(y, u, v, 1.));
  fragColor = vec4(rgb.rgb, %3);
})_";
 
  Video::ImageFormat& decoder;
  bool opaque{};
 
  VUYADecoder(Video::ImageFormat& d, bool opaque_)
      : decoder{d}
      , opaque{opaque_}
  {
  }
 
  std::pair<QShader, QShader> init(RenderList& r) override
  {
    auto& rhi = *r.state.rhi;
    const auto w = decoder.width, h = decoder.height;
 
    {
      auto tex = rhi.newTexture(QRhiTexture::RGBA8, {w, h}, 1, QRhiTexture::Flag{});
      tex->create();
 
      auto sampler = rhi.newSampler(
          QRhiSampler::Linear, QRhiSampler::Linear, QRhiSampler::None,
          QRhiSampler::ClampToEdge, QRhiSampler::ClampToEdge);
      sampler->create();
      samplers.push_back({sampler, tex});
    }
 
    // VUYX has undefined alpha, use 1.0; VUYA preserves alpha
    QString alpha = opaque ? "1.0" : "vuya.a";
 
    return score::gfx::makeShaders(
        r.state, vertexShader(),
        QString(frag).arg("").arg(colorMatrix(decoder)).arg(alpha));
  }
 
  void exec(RenderList&, QRhiResourceUpdateBatch& res, AVFrame& frame) override
  {
    auto pixels = frame.data[0];
    auto stride = frame.linesize[0];
    const auto w = decoder.width, h = decoder.height;
 
    QRhiTextureUploadEntry entry{
        0, 0, createTextureUpload(pixels, w, h, 4, stride)};
    res.uploadTexture(samplers[0].texture, {entry});
  }
};
 
}