[orx-fx] Add PolarToRectangular, RectangularToPolar and LineBlur

orx-fx/src/shaders/glsl/distort/polar-to-rectangular.frag

@@ -0,0 +1,33 @@
+#ifdef OR_IN_OUT
+in vec2 v_texCoord0;
+#else
+varying vec2 v_texCoord0;
+#endif
+
+uniform vec2 textureSize0;
+uniform sampler2D tex0;
+
+#ifndef OR_GL_FRAGCOLOR
+out vec4 o_color;
+#endif
+
+#define PI 3.141592653589793
+
+void main() {
+    vec2 uv = v_texCoord0 - vec2(0.5);
+    float arg = atan(uv.y, uv.x);
+    float radius = length(uv);
+    vec2 sourceUV = vec2(arg / (2*PI) + 0.5, radius/sqrt(0.5));
+
+    #ifndef OR_GL_TEXTURE2D
+    vec4 result = texture(tex0, sourceUV);
+    #else
+    vec4 result = texture2D(tex0, sourceUV);
+    #endif
+
+    #ifdef OR_GL_FRAGCOLOR
+    gl_FragColor = result;
+    #else
+    o_color = result;
+    #endif
+}