Added shaders examples resources

examples/resources/shaders/swirl.fs

@@ -0,0 +1,41 @@
+#version 330
+
+in vec2 fragTexCoord;
+
+out vec4 fragColor;
+
+uniform sampler2D texture0;
+uniform vec4 tintColor;
+
+// NOTE: Add here your custom variables
+
+const float renderWidth = 800;      // HARDCODED for example!
+const float renderHeight = 480;     // Use uniforms instead...
+
+float radius = 250.0;
+float angle = 0.8;
+
+uniform vec2 center = vec2(200, 200);
+
+void main (void)
+{
+    vec2 texSize = vec2(renderWidth, renderHeight);
+    vec2 tc = fragTexCoord*texSize;
+    tc -= center;
+    float dist = length(tc);
+
+    if (dist < radius) 
+    {
+        float percent = (radius - dist)/radius;
+        float theta = percent*percent*angle*8.0;
+        float s = sin(theta);
+        float c = cos(theta);
+        
+        tc = vec2(dot(tc, vec2(c, -s)), dot(tc, vec2(s, c)));
+    }
+
+    tc += center;
+    vec3 color = texture2D(texture0, tc/texSize).rgb;
+
+    fragColor = vec4(color, 1.0);;
+}