Duckstation/data/resources/shaders/reshade/Shaders/Deband.fx
2023-08-30 00:44:01 +10:00

252 lines
9.3 KiB
HLSL

/**
* Deband shader by haasn
* https://github.com/haasn/gentoo-conf/blob/xor/home/nand/.mpv/shaders/deband-pre.glsl
*
* Copyright (c) 2015 Niklas Haas
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
* Modified and optimized for ReShade by JPulowski
* https://reshade.me/forum/shader-presentation/768-deband
*
* Do not distribute without giving credit to the original author(s).
*
* 1.0 - Initial release
* 1.1 - Replaced the algorithm with the one from MPV
* 1.1a - Minor optimizations
* - Removed unnecessary lines and replaced them with ReShadeFX intrinsic counterparts
* 2.0 - Replaced "grain" with CeeJay.dk's ordered dithering algorithm and enabled it by default
* - The configuration is now more simpler and straightforward
* - Some minor code changes and optimizations
* - Improved the algorithm and made it more robust by adding some of the madshi's
* improvements to flash3kyuu_deband which should cause an increase in quality. Higher
* iterations/ranges should now yield higher quality debanding without too much decrease
* in quality.
* - Changed licensing text and original source code URL
* 3.0 - Replaced the entire banding detection algorithm with modified standard deviation and
* Weber ratio analyses which give more accurate and error-free results compared to the
* previous algorithm
* - Added banding map debug view
* - Added and redefined UI categories
* - Added depth detection (credits to spiro) which should be useful when banding only
* occurs in the sky texture for example
* - Fixed a bug in random number generation which was causing artifacts on the upper left
* side of the screen
* - Dithering is now applied only when debanding a pixel as it should be which should
* reduce the overall noise in the final texture
* - Minor code optimizations
* 3.1 - Switched to chroma-based analysis from luma-based analysis which was causing artifacts
* under some scenarios
* - Changed parts of the code which was causing compatibility issues on some renderers
*/
#include "ReShadeUI.fxh"
#include "ReShade.fxh"
uniform bool enable_weber <
ui_category = "Banding analysis";
ui_label = "Weber ratio";
ui_tooltip = "Weber ratio analysis that calculates the ratio of the each local pixel's intensity to average background intensity of all the local pixels.";
ui_type = "radio";
> = true;
uniform bool enable_sdeviation <
ui_category = "Banding analysis";
ui_label = "Standard deviation";
ui_tooltip = "Modified standard deviation analysis that calculates nearby pixels' intensity deviation from the current pixel instead of the mean.";
ui_type = "radio";
> = true;
uniform bool enable_depthbuffer <
ui_category = "Banding analysis";
ui_label = "Depth detection";
ui_tooltip = "Allows depth information to be used when analysing banding, pixels will only be analysed if they are in a certain depth. (e.g. debanding only the sky)";
ui_type = "radio";
> = false;
uniform float t1 <
ui_category = "Banding analysis";
ui_label = "Standard deviation threshold";
ui_max = 0.5;
ui_min = 0.0;
ui_step = 0.001;
ui_tooltip = "Standard deviations lower than this threshold will be flagged as flat regions with potential banding.";
ui_type = "slider";
> = 0.007;
uniform float t2 <
ui_category = "Banding analysis";
ui_label = "Weber ratio threshold";
ui_max = 2.0;
ui_min = 0.0;
ui_step = 0.01;
ui_tooltip = "Weber ratios lower than this threshold will be flagged as flat regions with potential banding.";
ui_type = "slider";
> = 0.04;
uniform float banding_depth <
ui_category = "Banding analysis";
ui_label = "Banding depth";
ui_max = 1.0;
ui_min = 0.0;
ui_step = 0.001;
ui_tooltip = "Pixels under this depth threshold will not be processed and returned as they are.";
ui_type = "slider";
> = 1.0;
uniform float range <
ui_category = "Banding detection & removal";
ui_label = "Radius";
ui_max = 32.0;
ui_min = 1.0;
ui_step = 1.0;
ui_tooltip = "The radius increases linearly for each iteration. A higher radius will find more gradients, but a lower radius will smooth more aggressively.";
ui_type = "slider";
> = 24.0;
uniform int iterations <
ui_category = "Banding detection & removal";
ui_label = "Iterations";
ui_max = 4;
ui_min = 1;
ui_tooltip = "The number of debanding steps to perform per sample. Each step reduces a bit more banding, but takes time to compute.";
ui_type = "slider";
> = 1;
uniform int debug_output <
ui_category = "Debug";
ui_items = "None\0Blurred (LPF) image\0Banding map\0";
ui_label = "Debug view";
ui_tooltip = "Blurred (LPF) image: Useful when tweaking radius and iterations to make sure all banding regions are blurred enough.\nBanding map: Useful when tweaking analysis parameters, continuous green regions indicate flat (i.e. banding) regions.";
ui_type = "combo";
> = 0;
// Reshade uses C rand for random, max cannot be larger than 2^15-1
uniform int drandom < source = "random"; min = 0; max = 32767; >;
float rand(float x)
{
return frac(x / 41.0);
}
float permute(float x)
{
return ((34.0 * x + 1.0) * x) % 289.0;
}
float3 PS_Deband(float4 vpos : SV_Position, float2 texcoord : TexCoord) : SV_Target
{
float3 ori = tex2Dlod(ReShade::BackBuffer, float4(texcoord, 0.0, 0.0)).rgb;
if (enable_depthbuffer && (ReShade::GetLinearizedDepth(texcoord) < banding_depth))
return ori;
// Initialize the PRNG by hashing the position + a random uniform
float3 m = float3(texcoord + 1.0, (drandom / 32767.0) + 1.0);
float h = permute(permute(permute(m.x) + m.y) + m.z);
// Compute a random angle
float dir = rand(permute(h)) * 6.2831853;
float2 o;
sincos(dir, o.y, o.x);
// Distance calculations
float2 pt;
float dist;
for (int i = 1; i <= iterations; ++i) {
dist = rand(h) * range * i;
pt = dist * BUFFER_PIXEL_SIZE;
h = permute(h);
}
// Sample at quarter-turn intervals around the source pixel
float3 ref[4] = {
tex2Dlod(ReShade::BackBuffer, float4(mad(pt, o, texcoord), 0.0, 0.0)).rgb, // SE
tex2Dlod(ReShade::BackBuffer, float4(mad(pt, -o, texcoord), 0.0, 0.0)).rgb, // NW
tex2Dlod(ReShade::BackBuffer, float4(mad(pt, float2(-o.y, o.x), texcoord), 0.0, 0.0)).rgb, // NE
tex2Dlod(ReShade::BackBuffer, float4(mad(pt, float2( o.y, -o.x), texcoord), 0.0, 0.0)).rgb // SW
};
// Calculate weber ratio
float3 mean = (ori + ref[0] + ref[1] + ref[2] + ref[3]) * 0.2;
float3 k = abs(ori - mean);
for (int j = 0; j < 4; ++j) {
k += abs(ref[j] - mean);
}
k = k * 0.2 / mean;
// Calculate std. deviation
float3 sd = 0.0;
for (int j = 0; j < 4; ++j) {
sd += pow(ref[j] - ori, 2);
}
sd = sqrt(sd * 0.25);
// Generate final output
float3 output;
if (debug_output == 2)
output = float3(0.0, 1.0, 0.0);
else
output = (ref[0] + ref[1] + ref[2] + ref[3]) * 0.25;
// Generate a binary banding map
bool3 banding_map = true;
if (debug_output != 1) {
if (enable_weber)
banding_map = banding_map && k <= t2 * iterations;
if (enable_sdeviation)
banding_map = banding_map && sd <= t1 * iterations;
}
/*------------------------.
| :: Ordered Dithering :: |
'------------------------*/
//Calculate grid position
float grid_position = frac(dot(texcoord, (BUFFER_SCREEN_SIZE * float2(1.0 / 16.0, 10.0 / 36.0)) + 0.25));
//Calculate how big the shift should be
float dither_shift = 0.25 * (1.0 / (pow(2, BUFFER_COLOR_BIT_DEPTH) - 1.0));
//Shift the individual colors differently, thus making it even harder to see the dithering pattern
float3 dither_shift_RGB = float3(dither_shift, -dither_shift, dither_shift); //subpixel dithering
//modify shift acording to grid position.
dither_shift_RGB = lerp(2.0 * dither_shift_RGB, -2.0 * dither_shift_RGB, grid_position); //shift acording to grid position.
return banding_map ? output + dither_shift_RGB : ori;
}
technique Deband <
ui_tooltip = "Alleviates color banding by trying to approximate original color values.";
>
{
pass
{
VertexShader = PostProcessVS;
PixelShader = PS_Deband;
}
}