From b1a90a7f915e7779aad975a70b503788b0a1b228 Mon Sep 17 00:00:00 2001
From: raysan5 <raysan5@gmail.com>
Date: Wed, 2 Sep 2015 02:44:16 +0200
Subject: Added some useful postprocessing shaders

Shaders come in two flavours:
- shaders/gl330: OpenGL 3.3+ (Windows, Linux, OSX)
- shaders/gles100:  OpenGL ES 2.0 (Android, RPI, HTML5)
---
 shaders/gl330/swirl.fs | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 shaders/gl330/swirl.fs

(limited to 'shaders/gl330/swirl.fs')

diff --git a/shaders/gl330/swirl.fs b/shaders/gl330/swirl.fs
new file mode 100644
index 00000000..18a47cec
--- /dev/null
+++ b/shaders/gl330/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 = 1280; 
+const float renderHeight = 720; 
+
+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);;
+}
\ No newline at end of file
-- 
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