// Copyright (c) 2012-2017 VideoStitch SAS
// Copyright (c) 2018 stitchEm

__global__ void FUNCTION_NAME_5(warpCoordInputKernel, fromInputToSphere, isWithin, inverseDistortionMetersTransform, inverseRadialPixelsTransform)
  (global_mem float2* g_odata,
  const int scaleFactor,
  const int inputWidth, const int inputHeight,
  const int inputLeft, const int inputRight, const int inputTop, const int inputBottom,
  const int panoWidth, const int panoHeight,
  const float2 panoScale,
  const vsfloat3x4 poseInverse,
  const float rigSphereRadius,
  const float2 inputScale,
  const vsDistortion distortion,
  const float2 centerShift
  ) {
  /* calculate normalized texture coordinates */
  const int x = get_global_id_x();
  const int y = get_global_id_y();
  if (x < scaleFactor * inputWidth && y < scaleFactor*inputHeight) {
    float2 uv = make_float2(((float) x) / scaleFactor, ((float)y) / scaleFactor);
    if (isWithin(uv, (float)inputWidth, (float)inputHeight, (float)inputLeft, (float)inputRight, (float)inputTop, (float)inputBottom)) {
      /**
       * Texture fetches are relative to the upper left, not the center.
       */
      uv.x -= (inputWidth - 1) / 2.0f;
      uv.y -= (inputHeight - 1) / 2.0f;
      uv = FUNCTION_NAME_4(mapInputToPanorama, fromInputToSphere, inverseDistortionMetersTransform, inverseRadialPixelsTransform)(uv, panoScale, poseInverse, rigSphereRadius, inputScale, distortion, centerShift);
      /**
       * Move to center-based coordinate
       */
      uv.x += (panoWidth - 1) / 2.0f;
      uv.y += (panoHeight - 1) / 2.0f;
      g_odata[(y * scaleFactor * inputWidth + x)] = make_float2(uv.x, uv.y);
    }
    else {
      g_odata[(y * scaleFactor * inputWidth + x)] = make_float2(INVALID_FLOW_VALUE, INVALID_FLOW_VALUE);
    }
  }
}