Add curve.shader

data/examples/curve.shader

@@ -0,0 +1,41 @@
+#define PI 3.14159265359
+
+uniform float strength<
+    string label = "Strength";
+    string widget_type = "slider";
+    float minimum = 0.0;
+    float maximum = 1.0;
+    float step = 0.001;
+> = 0.5;
+
+uniform float scale<
+    string label = "Scale";
+    string widget_type = "slider";
+    float minimum = 0.0;
+    float maximum = 1.0;
+    float step = 0.001;
+> = 1.0;
+
+uniform float4 curve_color = {0,0,0,0};
+
+float4 mainImage(VertData v_in) : TARGET
+{
+    float2 uv = v_in.uv;
+    const float ydiff = 1.0;
+    uv -= float2(0.5,ydiff);
+    uv.x *= ( uv_size.x / uv_size.y);
+    uv /= scale;
+    if(strength > 0.0){    
+        float d = tan((1.0-strength)*PI/2.0);
+        float r = length(float2(0.5*(uv_size.x / uv_size.y), d));
+        float2 center = float2(0.0,(1.0-ydiff)+d);
+        float pd = distance(uv, center);
+        if(pd < r)
+            return curve_color;
+        float angle = atan2(center.x-uv.x,center.y-uv.y);
+        uv = float2(uv.x + sin(angle)*(pd-r),(1.0-ydiff)-(pd-r));
+    }
+    uv.x /= ( uv_size.x / uv_size.y);
+    uv += float2(0.5,ydiff);
+    return image.Sample(textureSampler,uv);
+}