ShaderLookupDistort() : lookupTextureSize(512, 512), chroma(true) {
OVR::Util::Render::StereoConfig stereoConfig;
stereoConfig.SetHMDInfo(ovrHmdInfo);
const OVR::Util::Render::DistortionConfig & distortion =
stereoConfig.GetDistortionConfig();
// The Rift examples use a post-distortion scale to resize the
// image upward after distorting it because their K values have
// been chosen such that they always result in a scale > 1.0, and
// thus shrink the image. However, we can correct for that by
// finding the distortion scale the same way the OVR examples do,
// and then pre-multiplying the constants by it.
double postDistortionScale = 1.0 / stereoConfig.GetDistortionScale();
for (int i = 0; i < 4; ++i) {
K[i] = (float)(distortion.K[i] * postDistortionScale);
}
// red channel correction
chromaK[0] = glm::vec2(
ovrHmdInfo.ChromaAbCorrection[0],
ovrHmdInfo.ChromaAbCorrection[1]);
// blue channel correction
chromaK[1] = glm::vec2(
ovrHmdInfo.ChromaAbCorrection[2],
ovrHmdInfo.ChromaAbCorrection[3]);
for (int i = 0; i < 2; ++i) {
chromaK[i][0] = ((1.0 - chromaK[i][0]) * postDistortionScale) + 1.0;
chromaK[i][1] *= postDistortionScale;
}
lensOffset = 1.0f - (2.0f * ovrHmdInfo.LensSeparationDistance / ovrHmdInfo.HScreenSize);
}
DistortionHelper(const OVR::HMDInfo & ovrHmdInfo) {
OVR::Util::Render::StereoConfig stereoConfig;
stereoConfig.SetHMDInfo(ovrHmdInfo);
const OVR::Util::Render::DistortionConfig & distortion =
stereoConfig.GetDistortionConfig();
double postDistortionScale = 1.0 / stereoConfig.GetDistortionScale();
for (int i = 0; i < 4; ++i) {
K[i] = distortion.K[i] * postDistortionScale;
}
lensOffset = distortion.XCenterOffset;
eyeAspect = ovrHmdInfo.HScreenSize / 2.0f / ovrHmdInfo.VScreenSize;
}