// Target with smoothstep by possum
// https://www.shadertoy.com/view/Xsl3RX
// License Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License
// Contact the author for other licensing options

// type conversion
#define vec2 float2
#define vec3 float3
#define vec4 float4
#define ivec2 int2
#define ivec3 int3
#define ivec4 int4
#define mat2 float2x2
#define mat3 float3x3
#define mat4 float4x4
#define fract frac
#define mix lerp
#define iTime Time.x
#define iResolution ViewSize

// Always provided by OBS
uniform float4x4 ViewProj<
	bool automatic = true;
>;


// Provided by Stream Effects
uniform float4 Time<
	bool automatic = true;
>;
uniform float4 ViewSize<
	bool automatic = true;
>;
uniform texture2d InputA<
	bool automatic = true;
>;
uniform float4x4 Random<
	bool automatic = true;
>;


// Shader Parameters
uniform float pRings<
	string name = "Rings";
	string field_type = "slider";
	float minimum = 1.0;
	float maximum = 50.0;
	float step = 0.01;
	float scale = 1.;
> = 5.0;
uniform float pVelocity<
	string name = "Ring Velocity";
	string field_type = "slider";
	float minimum = 0.1;
	float maximum = 10.0;
	float step = 0.01;
	float scale = 1.;
> = 1.0;
uniform float pBorder<
	string name = "Border Size";
	string field_type = "slider";
	float minimum = 0.1;
	float maximum = 100.0;
	float step = 0.1;
	float scale = 0.001;
> = 1.;

// convenience values
#define PI		3.1415926f
#define TAU		6.2831853f
#define TwoPI	6.2831853f
#define HalfPI	1.5707963f
#define deg30	0.20943951

float mod(float x, float y) {
  return x - y * floor(x / y);
}

// ---------- Shader Code
sampler_state def_sampler {
	Filter = Linear;
	AddressU  = Clamp;
	AddressV  = Clamp;
};

sampler_state imageSampler {
	Filter = Point;
	AddressU  = Clamp;
	AddressV  = Clamp;
};

struct VertFragData {
	float4 pos : POSITION;
	float2 uv  : TEXCOORD0;
};

VertFragData VSDefault(VertFragData vtx) {
	vtx.pos = mul(float4(vtx.pos.xyz, 1.0), ViewProj);
	return vtx;
}

void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
	float2 position = fragCoord.xy / ViewSize.xy;
	float aspect = ViewSize.x / ViewSize.y;
	position.x *= aspect;
	float dist = distance(position, float2( aspect * 0.5, 0.5));
	float offset = Time.x * pVelocity;
	float conv = pRings * 1.;
	float v = dist * conv - offset;
	float ringr = floor(v);
	float ringv = abs( dist - (ringr + float( frac(v) > 0.5) + offset) / conv);
	float color = smoothstep( -pBorder, pBorder, ringv);
	if ( mod(ringr, 2.) == 1.) color = 1. - color;
	fragColor = vec4(color, color, color, 1.);
}


float4 PSDefault(VertFragData vtx) : TARGET {
	float4 col = float4(1., 1., 1., 1.);
	mainImage(col, vtx.uv * ViewSize.xy);
	return col;
}

technique Draw
{
	pass
	{
		vertex_shader = VSDefault(vtx);
		pixel_shader  = PSDefault(vtx);
	}
}