examples/sahders: Add concentric rings shader (ShaderToy: Xsl3RX) (#310)

data/examples/shaders/source/shadertoy-Xsl3RX.effect

@@ -0,0 +1,145 @@
+// 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;
+	string name = "View Projection Matrix";
+>;
+
+
+// Provided by Stream Effects
+uniform float4 Time<
+    // x: Time in seconds since the source was created.
+    // y: Time in the current second.
+    // z: Total seconds passed since the source was created.
+    // w: Reserved
+	bool automatic = true;
+    string name = "Time Array";
+	string description = "A float4 value containing the total time, rendering time and the time since the last tick. The last value is a random number between 0 and 1.";
+>;
+uniform float4 ViewSize<
+    // x: Width
+    // y: Height
+    // z: 1. / Width
+    // w: 1. / Height
+	bool automatic = true;
+>;
+uniform texture2d InputA<
+	bool automatic = true;
+>;
+uniform float4x4 Random<
+	bool automatic = true;
+	string name = "Random Array";
+	string description = "A float4x4 value containing random values between 0 and 1";
+>;
+
+
+// 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); 
+	}
+}