Update/merge examples back into main repo (#192)

Examples/resources/shaders/glsl120/swirl.fs

@@ -0,0 +1,44 @@
+#version 120
+
+// Input vertex attributes (from vertex shader)
+varying vec2 fragTexCoord;
+varying vec4 fragColor;
+
+// Input uniform values
+uniform sampler2D texture0;
+uniform vec4 colDiffuse;
+
+// NOTE: Add here your custom variables
+
+// NOTE: Render size values should be passed from code
+const float renderWidth = 800;
+const float renderHeight = 450;
+
+float radius = 250.0;
+float angle = 0.8;
+
+uniform vec2 center;
+
+void main()
+{
+    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;
+    vec4 color = texture2D(texture0, tc/texSize)*colDiffuse*fragColor;;
+
+    gl_FragColor = vec4(color.rgb, 1.0);;
+}