mirror of https://github.com/Xaymar/obs-StreamFX
100 lines
3.4 KiB
Plaintext
100 lines
3.4 KiB
Plaintext
// AUTOGENERATED COPYRIGHT HEADER START
|
|
// Copyright (C) 2019-2023 Michael Fabian 'Xaymar' Dirks <info@xaymar.com>
|
|
// AUTOGENERATED COPYRIGHT HEADER END
|
|
|
|
#include "common.effect"
|
|
|
|
// # Linear Optimization
|
|
// While the normal way is to sample every texel in the pSize, linear optimization
|
|
// takes advantage of the fact that most people, especially after compression,
|
|
// will not be able to tell the difference between a linear approximation and
|
|
// the actual thing.
|
|
//
|
|
// Instead of sampling every texel like this:
|
|
//
|
|
// |Tx|Tx|Tx|Tx|Tx|
|
|
// Tx|-2|-1| 0|+1|+2|
|
|
//
|
|
// Linear optimization will sample like this:
|
|
//
|
|
// |Tx|Tx|Tx|Tx|Tx|
|
|
// Tx| -1 | 0| +1 |
|
|
//
|
|
// This effectively removes half the necessary samples and looks identical when
|
|
// when used with box blur. However there is an edge case when the blur width
|
|
// is not a multiple of two, where two additional samples have to be spent on
|
|
// reading the outer edge:
|
|
//
|
|
// |Tx|Tx|Tx|Tx|Tx|Tx|Tx|
|
|
// Tx|-2| -1 | 0| +1 |+2|
|
|
//
|
|
// or this alternative pattern that uses two less samples:
|
|
//
|
|
// |Tx|Tx|Tx|Tx|Tx|Tx|Tx|
|
|
// Tx| 0 | +1 | +2 |+3|
|
|
//
|
|
// or this alternative pattern that also uses two less samples:
|
|
//
|
|
// |Tx|Tx|Tx|Tx|Tx|Tx|Tx|
|
|
// Tx| -2 | -1~~+1 | +2 |
|
|
//
|
|
// With careful planning this can even be used for other types of Blur, such as
|
|
// Gaussian Blur, which suffers a larger hit - however there are better and
|
|
// faster alternatives than linear sampling with Gaussian Blur, such as
|
|
// Dual Filtering ("Dual Kawase").
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Defines
|
|
//------------------------------------------------------------------------------
|
|
#define MAX_BLUR_SIZE 128
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Technique: Directional / Area
|
|
//------------------------------------------------------------------------------
|
|
float4 PSBlur1D(VertexInformation vtx) : TARGET {
|
|
float4 final = pImage.Sample(LinearClampSampler, vtx.uv) * GetKernelAt(0);
|
|
bool is_odd = ((int(round(pSize)) % 2) == 1);
|
|
|
|
// y = yes, s = skip, b = break
|
|
// Size-> | 1| 2| 3| 4| 5| 6| 7|
|
|
// -------+--+--+--+--+--+--+--+
|
|
// n=1 | b| y| y| y| y| y| y|
|
|
// n=2 | |bs| s| s| s| s| s|
|
|
// n=3 | | b| b| y| y| y| y|
|
|
// n=4 | | | |bs| s| s| s|
|
|
// n=5 | | | | b| b| y| y|
|
|
// n=6 | | | | | |bs| s|
|
|
// n=7 | | | | | | b| b|
|
|
// n=8 | | | | | | | |
|
|
|
|
// Loop unrolling is only possible with a fixed known maximum.
|
|
// Some compilers may unroll up to x iterations, but most will not.
|
|
for (int n = 1; n <= MAX_BLUR_SIZE; n+=2) {
|
|
// Different from normal box, early exit instead of late exit.
|
|
if (n >= pSize) {
|
|
break;
|
|
}
|
|
|
|
// TODO: Determine better position than 0.5 for gaussian approximation.
|
|
float2 nstep = (pImageTexel * pStepScale) * (n + 0.5);
|
|
float kernel = kernelAt(n) + kernelAt(n + 1);
|
|
final += pImage.Sample(LinearClampSampler, vtx.uv + nstep) * kernel;
|
|
final += pImage.Sample(LinearClampSampler, vtx.uv - nstep) * kernel;
|
|
}
|
|
if (is_odd) {
|
|
float kernel = kernelAt(pSize);
|
|
float2 nstep = (pImageTexel * pStepScale) * pSize;
|
|
final += pImage.Sample(LinearClampSampler, vtx.uv + nstep) * kernel;
|
|
final += pImage.Sample(LinearClampSampler, vtx.uv - nstep) * kernel;
|
|
}
|
|
|
|
return final;
|
|
}
|
|
|
|
technique Draw {
|
|
pass {
|
|
vertex_shader = VSDefault(vtx);
|
|
pixel_shader = PSBlur1D(vtx);
|
|
}
|
|
}
|