ReShade Forum: How to write to SV

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TOPIC: How to write to SV_Depth?

How to write to SV_Depth? 1 year 7 months ago #1

Fu-Bama
Offline

I'm trying to UV-distort the depth buffer along with the image distortion, for effects that follow and use depth.
Problem is that I don't know how to write to the depth buffer SV_Depth.
I tried to write the depth to Pass1 alpha channel, then in second pass, that targets SV_Depth, return the alpha channel from the first one.
But it gives an error undefined variable "_return"

Shader Code:

Warning: Spoiler! [ Click to expand ]

/*
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/.
*/

// Perfect Perspective PS ver. 2.0

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

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

uniform int FOV <
	ui_label = "Field of View";
	ui_tooltip = "Match in-game Field of View";
	ui_type = "drag";
	ui_min = 45; ui_max = 120;
> = 90;

uniform int Type <
	ui_label = "Type of FOV";
	ui_tooltip = "If image bulges in movement, change it to Diagonal. When proportions are distorted, choose Vertical";
	ui_type = "combo";
	ui_items = "Horizontal FOV\0Diagonal FOV\0Vertical FOV\0";
> = 0;

uniform float Zooming <
	ui_label = "Adjust Borders Size";
	ui_type = "drag";
	ui_min = 0.0; ui_max = 3.0; ui_step = 0.001;
> = 1.0;

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

#include "ReShade.fxh"

// Stereographic-Gnomonic lookup function
// Input data:
	// SqrTanFOVq >> squared tangent of quater FOV angle
	// Coordinates >> UV coordinates (from -1, to 1), where (0,0) is at the center of the screen
float Formula(float SqrTanFOVq, float2 Coordinates)
{
	float Result = 1.0 - SqrTanFOVq;
	Result /= 1.0 - SqrTanFOVq * (Coordinates.x * Coordinates.x + (Coordinates.y * Coordinates.y));
	return Result;
}

// Shader pass
float4 PerfectPerspectivePS(float4 vois : SV_Position, float2 texcoord : TexCoord) : SV_Target
{
	// Get Pixel Position
	float2 SphCoord = texcoord;
	// Get Aspect Ratio
	float AspectR = 1.0 / ReShade::AspectRatio;

	// Convert FOV type..
	float FovType = 1.0;
		if (Type == 1) // ..to diagonal
		{
			FovType = sqrt(AspectR * AspectR + 1.0);
		}
		else if (Type == 2) // ..to vertical
		{
			FovType = AspectR;
		}

	// Convert 1/4 FOV to radians and calc tangent squared
	float SqrTanFOVq = float(FOV) * 0.25;
		SqrTanFOVq = radians(SqrTanFOVq);
		SqrTanFOVq = tan(SqrTanFOVq);
		SqrTanFOVq *= SqrTanFOVq;

	// Convert UV to Radial Coordinates
	SphCoord = SphCoord * 2.0 - 1.0;
	// Aspect Ratio correction
	SphCoord.y *= AspectR;
	// Zoom in image and adjust FOV type (pass 1 of 2)
	SphCoord *= Zooming / FovType;

	// Stereographic-Gnomonic lookup
	SphCoord *= Formula(SqrTanFOVq, SphCoord);

	// Adjust FOV type (pass 2 of 2)
	SphCoord *= FovType;

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

	// Back to UV Coordinates
	SphCoord = SphCoord * 0.5 + 0.5;

	// Sample display image
	float4 Display;
	Display.rgb = tex2D(ReShade::BackBuffer, SphCoord).rgb;
	Display.a = tex2D(ReShade::DepthBuffer, SphCoord).r;

	// 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 float4(Color, 0);
	}
}

float AdjustDepthPS(float4 vois : SV_Position, float2 texcoord : TexCoord) : SV_Depth
{
	return tex2D(ReShade::BackBuffer, texcoord).a;
}

technique PerfectPerspectiveBeta
{
	pass ColorPass
	{
		VertexShader = PostProcessVS;
		PixelShader = PerfectPerspectivePS;
	}
	pass DepthPass
	{
		VertexShader = PostProcessVS;
		PixelShader = AdjustDepthPS;
	}
}

My shaders at GitHub
Donate me a ko-fi

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How to write to SV_Depth? 1 year 7 months ago #2

crosire
Offline

This is not going to work, unfortunately. The depth-stencil buffer bound for writing is not the one you get as input.
In fact ReShade does not guarantee a depth buffer being bound during post-processing at all, it's only defined to at least bind a stencil buffer when the render target size matches that of the game viewport (SMAA needs this). A depth buffer doesn't make much sense during post-processing usually, because we only draw fullscreen primitives that should not be depth sorted.
Depth data you get as input comes straight from the depth texture the game had bound as depth buffer during rendering, but it's considered immutable at this point like all resources ReShade gives access to. The backbuffer is the one and only exception. Giving write access to any other resource would come with a heavy performance penalty and is therefore not allowed nor implemented.

Cheers, crosire =)

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How to write to SV_Depth? 1 year 7 months ago #3

Fu-Bama Offline	Thanks for the answer.
	My shaders at GitHub Donate me a ko-fi The administrator has disabled public write access.