void SetParameters(const FRenderingCompositePassContext& Context, IPooledRenderTarget& DistortionRT)
{
const FPixelShaderRHIParamRef ShaderRHI = GetPixelShader();
FTextureRHIParamRef DistortionTextureValue = DistortionRT.GetRenderTargetItem().ShaderResourceTexture;
FTextureRHIParamRef SceneColorTextureValue = GSceneRenderTargets.GetSceneColor()->GetRenderTargetItem().ShaderResourceTexture;
// Here we use SF_Point as in fullscreen the pixels are 1:1 mapped.
SetTextureParameter(
Context.RHICmdList,
ShaderRHI,
DistortionTexture,
DistortionTextureSampler,
TStaticSamplerState<SF_Point,AM_Clamp,AM_Clamp,AM_Clamp>::GetRHI(),
DistortionTextureValue
);
SetTextureParameter(
Context.RHICmdList,
ShaderRHI,
SceneColorTexture,
SceneColorTextureSampler,
TStaticSamplerState<SF_Bilinear,AM_Clamp,AM_Clamp,AM_Clamp>::GetRHI(),
SceneColorTextureValue
);
FIntPoint SceneBufferSize = GSceneRenderTargets.GetBufferSizeXY();
FIntRect ViewportRect = Context.GetViewport();
FVector4 SceneColorRectValue = FVector4((float)ViewportRect.Min.X/SceneBufferSize.X,
(float)ViewportRect.Min.Y/SceneBufferSize.Y,
(float)ViewportRect.Max.X/SceneBufferSize.X,
(float)ViewportRect.Max.Y/SceneBufferSize.Y);
SetShaderValue(Context.RHICmdList, ShaderRHI, SceneColorRect, SceneColorRectValue);
}
// Convert f-stop and focal distance into projected size in half resolution pixels.
// Setup depth based blur.
static FVector CircleDofCoc(const FRenderingCompositePassContext& Context)
{
// Convert FOV to focal length,
//
// fov = 2 * atan(d/(2*f))
// where,
// d = sensor dimension (APS-C 24.576 mm)
// f = focal length
//
// f = 0.5 * d * (1/tan(fov/2))
float HalfFOV = FMath::Atan(1.0f / Context.View.ViewMatrices.ProjMatrix.M[0][0]);
float FocalLength = 0.5f * 24.576f * (1.0f/FMath::Tan(HalfFOV));
// Convert focal distance in world position to mm.
// Conversion is 1 world position = 1 cm.
float Distance = Context.View.FinalPostProcessSettings.DepthOfFieldFocalDistance;
Distance *= 10.0f;
// Convert f-stop, focal length, and focal distance to
// projected circle of confusion size at infinity in mm.
//
// coc = f*f / (n * (d - f))
// where,
// f = focal length
// d = focal distance
// n = fstop (where n is the "n" in "f/n")
float Radius = FocalLength * FocalLength / (Context.View.FinalPostProcessSettings.DepthOfFieldFstop * (Distance - FocalLength));
// Scale so that APS-C 24.576 mm = full frame.
// Convert mm to pixels.
float Width = (float)Context.GetViewport().Size().X;
Radius = Radius * Width * (1.0f/24.576f);
// Convert diameter to radius at half resolution (algorithm radius is at half resolution).
Radius *= 0.25f;
// Comment out for now, allowing settings which the algorithm cannot cleanly do.
#if 0
// Limit to algorithm max size.
if(Radius > 6.0f)
{
Radius = 6.0f;
}
#endif
// The DepthOfFieldDepthBlurAmount = km at which depth blur is 50%.
// Need to convert to cm here.
return FVector(
Radius,
1.0f/(Context.View.FinalPostProcessSettings.DepthOfFieldDepthBlurAmount * 100000.0),
Context.View.FinalPostProcessSettings.DepthOfFieldDepthBlurRadius * Width / 1920.0f);
}
