distortion correction - conformal perspective

/*
Copyright (c) 2018 Jacob Maximilian Fober

This work is licensed under the Creative Commons 
Attribution-ShareAlike 4.0 International License. 
To view a copy of this license, visit 
http://creativecommons.org/licenses/by-sa/4.0/.
*/

// PerspTest PS

  ////////////////////
 /////// MENU ///////
////////////////////

uniform float Strength <
	ui_type = "drag";
	ui_min = 0.0; ui_max = 1.0;
> = 0.5;

  //////////////////////
 /////// SHADER ///////
//////////////////////

#include "ReShade.fxh"

float Overlay(float coord)
{
	float a = max(coord, 0.5) * 2.0 - 1.0;
	a *= a;
	a *= 0.5;
	float b = 1.0 - min(coord, 0.5) * 2.0;
	b *= b;
	b = 1.0 - b;
	b *= 0.5;
	return a + b;
}

float3 PerspTestPS(float4 vois : SV_Position, float2 texcoord : TexCoord) : SV_Target
{
	// Get Aspect Ratio
	float AspectR = ReShade::AspectRatio;

	// Distortion correction amount
	float2 SphCoord = lerp(texcoord, float2(Overlay(texcoord.x), Overlay(texcoord.y)), Strength);

	// Sample display image
	float3 Display = tex2D(ReShade::BackBuffer, SphCoord).rgb;

	return Display;
}


technique PerspTest
{
	pass
	{
		VertexShader = PostProcessVS;
		PixelShader = PerspTestPS;
	}
}

/*
Copyright (c) 2018 Jacob Maximilian Fober

This work is licensed under the Creative Commons 
Attribution-ShareAlike 4.0 International License. 
To view a copy of this license, visit 
http://creativecommons.org/licenses/by-sa/4.0/.
*/

// Perspective Test PS

  ////////////////////
 /////// MENU ///////
////////////////////

uniform float Strength <
	ui_tooltip = "Distortion scale. 0 is Linear perspective and 1 is LSD trip.";
	ui_type = "drag";
	ui_min = 0.0; ui_max = 1.0;
> = 1.0;

uniform float3 Color <
	ui_label = "Background Color";
	ui_type = "Color";
> = float3(0.027, 0.027, 0.027);

uniform int FOV <
	ui_label = "Field of View";
	ui_tooltip = "In-game horizontal Field of View";
	ui_type = "drag";
	ui_min = 60; ui_max = 110;
> = 90;

uniform int Type <
	ui_label = "Type of alignment";
	ui_type = "combo";
	ui_items = "horizontal\0vertical\0";
> = 1;


  //////////////////////
 /////// SHADER ///////
//////////////////////

#include "ReShade.fxh"

float3 PerspectiveTestPS(float4 vois : SV_Position, float2 texcoord : TexCoord) : SV_Target
{
	// Convert FOV to half-radians and calc cotangent
	float ctanFOVh = radians(FOV * 0.5);
	ctanFOVh = cos(ctanFOVh) / sin(ctanFOVh);
	// Get Aspect Ratio
	float AspectR = ReShade::AspectRatio;
	float Edge;
	float2 SphCoord = texcoord;


	// Horizontal
	if (Type == 0)
	{
		Edge = 1.0;
	}

	// Vertical
	else
	{
		Edge = 1.0 / AspectR;
	}


	// Convert UV to Radial Coordinates
	SphCoord = SphCoord * 2.0 - 1.0;

	// Aspect Ratio correction
	SphCoord.y /= AspectR;

	// Wierd transform
	SphCoord.x *=
		(ctanFOVh + length( float2(SphCoord.x, ctanFOVh) ))
		/ 
		(ctanFOVh + length( float2(Edge, ctanFOVh) ))
	;
	SphCoord.y *=
	(ctanFOVh + length( float2(SphCoord.y, ctanFOVh) ))
	/ 
	(ctanFOVh + length( float2(Edge, ctanFOVh) ))
	;

	// Aspect Ratio back to square
	SphCoord.y *= AspectR;

	// Back to UV Coordinates
	SphCoord = (SphCoord + 1.0) * 0.5;

	// Distortion correction amount
	SphCoord = lerp(texcoord, SphCoord, Strength);

	// Sample display image
	float3 Display = tex2D(ReShade::BackBuffer, SphCoord).rgb;


	// Mask out outside-border pixels
	if (SphCoord.x < 1.0 && SphCoord.x > 0.0 && SphCoord.y < 1.0 && SphCoord.y > 0.0)
	{
		return Display;
	}
	else
	{
		return Color;
	}
}


technique PerspectiveTest
{
	pass
	{
		VertexShader = PostProcessVS;
		PixelShader = PerspectiveTestPS;
	}
}

/*
	Credits :: icelaglace, a.o => (ported from some blog, author unknown)
	Credits :: Pascal aka Marty McFly
	Amateur port by Insomnia 
*/


uniform float fFisheyeZoom <
	ui_type = "drag";
	ui_min = 0.5; ui_max = 1.0;
	ui_label = "Fish Eye Zoom";
	ui_tooltip = "Lens zoom to hide bugged edges due to texcoord modification";
> = 0.55;
uniform float fFisheyeDistortion <
	ui_type = "drag";
	ui_min = -0.300; ui_max = 0.300;
	ui_label = "Fisheye Distortion";
	ui_tooltip = "Distortion of image";
> = 0.01;
uniform float fFisheyeDistortionCubic <
	ui_type = "drag";
	ui_min = -0.300; ui_max = 0.300;
	ui_label = "Fisheye Distortion Cubic";
	ui_tooltip = "Distortion of image, cube based";
> = 0.7;
uniform float fFisheyeColorshift <
	ui_type = "drag";
	ui_min = -0.10; ui_max = 0.10;
	ui_label = "Colorshift";
	ui_tooltip = "Amount of color shifting";
> = 0.002;

#include "ReShade.fxh"

float3 FISHEYE_CAPass(float4 position : SV_Position, float2 texcoord : TexCoord) : SV_Target
{
	float3 color = tex2D(ReShade::BackBuffer, texcoord).rgb;

	float4 coord=0.0;
	coord.xy=texcoord.xy;
	coord.w=0.0;

	color.rgb = 0.0;
	  
	float3 eta = float3(1.0+fFisheyeColorshift*0.9,1.0+fFisheyeColorshift*0.6,1.0+fFisheyeColorshift*0.3);
	float2 center;
	center.x = coord.x-0.5;
	center.y = coord.y-0.5;
	float LensZoom = 1.0/fFisheyeZoom;

	float r2 = (texcoord.y-0.5) * (texcoord.y-0.5);// + (texcoord.y-0.5) * (texcoord.y-0.5);
	float f = 0;

	if( fFisheyeDistortionCubic == 0.0){
		f = 1 + r2 * fFisheyeDistortion;
	}else{
                f = 1 + r2 * (fFisheyeDistortion + fFisheyeDistortionCubic * sqrt(r2));
	};

	float x = f*LensZoom*(coord.x-0.5)+0.5;
	float y = f*LensZoom*(coord.y-0.5)+0.5;
	float2 rCoords = (f*eta.r)*LensZoom*(center.xy*0.5)+0.5;
	float2 gCoords = (f*eta.g)*LensZoom*(center.xy*0.5)+0.5;
	float2 bCoords = (f*eta.b)*LensZoom*(center.xy*0.5)+0.5;
	
	color.x = tex2D(ReShade::BackBuffer,rCoords).r;
	color.y = tex2D(ReShade::BackBuffer,gCoords).g;
	color.z = tex2D(ReShade::BackBuffer,bCoords).b;
	
	return color.rgb;

}


technique FISHEYE_CA_HORIZONTAL
{
	pass
	{
		VertexShader = PostProcessVS;
		PixelShader = FISHEYE_CAPass;
	}
}

/*
	Credits :: icelaglace, a.o => (ported from some blog, author unknown)
	Credits :: Pascal aka Marty McFly
	Amateur port by Insomnia 
*/


uniform float fFisheyeZoom <
	ui_type = "drag";
	ui_min = 0.5; ui_max = 1.0;
	ui_label = "Fish Eye Zoom";
	ui_tooltip = "Lens zoom to hide bugged edges due to texcoord modification";
> = 0.55;
uniform float fFisheyeDistortion <
	ui_type = "drag";
	ui_min = -0.300; ui_max = 0.300;
	ui_label = "Fisheye Distortion";
	ui_tooltip = "Distortion of image";
> = 0.01;
uniform float fFisheyeDistortionCubic <
	ui_type = "drag";
	ui_min = -0.300; ui_max = 0.300;
	ui_label = "Fisheye Distortion Cubic";
	ui_tooltip = "Distortion of image, cube based";
> = 0.7;
uniform float fFisheyeColorshift <
	ui_type = "drag";
	ui_min = -0.10; ui_max = 0.10;
	ui_label = "Colorshift";
	ui_tooltip = "Amount of color shifting";
> = 0.002;

#include "ReShade.fxh"

float3 FISHEYE_CAPass(float4 position : SV_Position, float2 texcoord : TexCoord) : SV_Target
{
	float3 color = tex2D(ReShade::BackBuffer, texcoord).rgb;

	float4 coord=0.0;
	coord.xy=texcoord.xy;
	coord.w=0.0;

	color.rgb = 0.0;
	  
	float3 eta = float3(1.0+fFisheyeColorshift*0.9,1.0+fFisheyeColorshift*0.6,1.0+fFisheyeColorshift*0.3);
	float2 center;
	center.x = coord.x-0.5;
	center.y = coord.y-0.5;
	float LensZoom = 1.0/fFisheyeZoom;

	float r2 = (texcoord.x-0.5) * (texcoord.x-0.5);// + (texcoord.y-0.5) * (texcoord.y-0.5);
	float f = 0;

	if( fFisheyeDistortionCubic == 0.0){
		f = 1 + r2 * fFisheyeDistortion;
	}else{
                f = 1 + r2 * (fFisheyeDistortion + fFisheyeDistortionCubic * sqrt(r2));
	};

	float x = f*LensZoom*(coord.x-0.5)+0.5;
	float y = f*LensZoom*(coord.y-0.5)+0.5;
	float2 rCoords = (f*eta.r)*LensZoom*(center.xy*0.5)+0.5;
	float2 gCoords = (f*eta.g)*LensZoom*(center.xy*0.5)+0.5;
	float2 bCoords = (f*eta.b)*LensZoom*(center.xy*0.5)+0.5;
	
	color.x = tex2D(ReShade::BackBuffer,rCoords).r;
	color.y = tex2D(ReShade::BackBuffer,gCoords).g;
	color.z = tex2D(ReShade::BackBuffer,bCoords).b;
	
	return color.rgb;

}


technique FISHEYE_CA_VERTICAL
{
	pass
	{
		VertexShader = PostProcessVS;
		PixelShader = FISHEYE_CAPass;
	}
}