obs-StreamFX/data/examples/shaders/filter/swirl.effect

// AUTOGENERATED COPYRIGHT HEADER START
// Copyright (C) 2021 Radegast Stravinsky <radegast.ffxiv@gmail.com>
// Copyright (C) 2023 Michael Fabian 'Xaymar' Dirks <info@xaymar.com>
// AUTOGENERATED COPYRIGHT HEADER END
// Copyright 2021 Radegast Stravinsky <radegast.ffxiv@gmail.com>
//
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//
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#include "../base.effect"
//-----------------------------------------------------------------------------
// Uniforms
//-----------------------------------------------------------------------------

// Provided by StreamFX
uniform float4 Time<
	bool automatic = true;
>;
uniform float4 ViewSize<
	bool automatic = true;
>;
uniform texture2d InputA<
	bool automatic = true;
>;

uniform float2 coordinates<
	string name = "Coordinates (X, Y)";
	string description = "Determines the center of the effect.";
	string field_type = "slider";
	float2 step = {0.01, 0.01};
	float2 minimum = {0.0, 0.0};
	float2 maximum = {1.0, 1.0};
> = {0.5, 0.5};

uniform float angle<
	string name = "Angle";
	string description = "The angle in degrees to twist the image.";
	string field_type = "slider";
	float minimum = -1800.0;
	float maximum = 1800.0;
> = 270.0;

uniform float radius<
	string name = "Radius";
	string description = "The radius of the effect.";
	string field_type = "slider";
	float step = 0.01;
	float minimum = 0.0;
	float maximum = 1.0;
> = 0.5;

uniform float tension<
	string name = "Tension";
	string description = "Controls how rapidly the distortion reaches the maximum value.";
	string field_type = "slider";
	float step = 0.01;
	float minimum = 0.0;
	float maximum = 10.0;
> = 1.0;

uniform float aspect_ratio<
	string name = "Aspect Ratio";
	string description = "Adjusts the aspect ratio for the associated distortion.";
	string field_type = "slider";
	float step = 0.01;
	float minimum = -1;
	float maximum = 1;
> = 0.0;

uniform bool animate<
	string name = "Animate";
	string description = "Animates the effect, making it twist back and forth.";
> = false;

uniform bool inverse_angle<
	string name = "Use Inverse Angle";
	string description = "Inverts the angle, making the edges more distorted than the center.";
> = false;

//-----------------------------------------------------------------------------
// Structs
//-----------------------------------------------------------------------------
struct VertexData {
	float4 pos : POSITION;
	float2 uv : TEXCOORD0;
};

//-----------------------------------------------------------------------------
// Samplers
//-----------------------------------------------------------------------------
sampler_state texture_sampler {
	Filter    = Linear;
	AddressU  = Mirror;
	AddressV  = Mirror;
};

//-----------------------------------------------------------------------------
// Functions
//-----------------------------------------------------------------------------

float2 swirl_transform (float percent, float2 input_vertex, float2 effect_center) {
	float theta = percent * percent * radians(angle * (animate == true ? sin(Time.x) : 1.0) );
	float s =  sin(theta);
	float c =  cos(theta);
	float2x2 transform = float2x2(
		c, -s,
		s, c
	);
	return mul(transform, input_vertex-effect_center);
}

//-----------------------------------------------------------------------------
// Shaders
//-----------------------------------------------------------------------------
float4 PSSwirl(VertexData vtx) : TARGET {
	VertexData vertex_out;
	vertex_out.pos = vtx.pos;

	float2 effect_center = coordinates/2.0;
	float ar_raw = 1. * ViewSize.y / ViewSize.x;
	float ar = lerp(ar_raw, 1, aspect_ratio);

	vertex_out.uv = 1. * vtx.uv - effect_center;

	effect_center.x /= ar;
	vertex_out.uv.x /= ar;

	float dist = distance(vertex_out.uv, effect_center);
	if (dist < radius)
	{
		float tension_radius = lerp(radius-dist, radius, tension);
		float percent = (radius-dist) /tension_radius;
		percent = inverse_angle == 0 ? percent : 1 - percent;

		vertex_out.uv = swirl_transform(percent, vertex_out.uv, effect_center);
		vertex_out.uv += (2 * effect_center);

		vertex_out.uv.x *= ar;

		return InputA.Sample(texture_sampler, vertex_out.uv);
	}
	else
	{
		return InputA.Sample(texture_sampler, vtx.uv );
	}
}

technique Swirl
{
	pass
	{
		vertex_shader = DefaultVertexShader(vtx);
		pixel_shader = PSSwirl(vtx);
	}
}