Added distortion shader for testing

examples/resources/shaders/base.vs

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+#version 330
+
+// Input vertex attributes
+in vec3 vertexPosition;
+in vec2 vertexTexCoord;
+in vec3 vertexNormal;
+in vec4 vertexColor;
+
+// Input uniform values
+uniform mat4 mvpMatrix;
+
+// Output vertex attributes (to fragment shader)
+out vec2 fragTexCoord;
+out vec4 fragColor;
+
+// NOTE: Add here your custom variables 
+
+void main()
+{
+    // Send vertex attributes to fragment shader
+    fragTexCoord = vertexTexCoord;
+    fragColor = vertexColor;
+    
+    // Calculate final vertex position
+    gl_Position = mvpMatrix*vec4(vertexPosition, 1.0);
+}

examples/resources/shaders/distortion.fs

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+#version 330
+
+// Input vertex attributes (from vertex shader)
+in vec2 fragTexCoord;
+
+// Input uniform values
+uniform sampler2D texture0;
+
+// Output fragment color
+out vec4 finalColor;
+
+// NOTE: Add here your custom variables
+const vec2 LeftLensCenter = vec2(0.2863248, 0.5);
+const vec2 RightLensCenter = vec2(0.7136753, 0.5);
+const vec2 LeftScreenCenter = vec2(0.25, 0.5);
+const vec2 RightScreenCenter = vec2(0.75, 0.5);
+const vec2 Scale = vec2(0.25, 0.45);    //vec2(0.1469278, 0.2350845);
+const vec2 ScaleIn = vec2(4, 2.2222);
+const vec4 HmdWarpParam = vec4(1, 0.22, 0.24, 0);
+
+/*
+// Another set of default values
+ChromaAbCorrection = {1.0, 0.0, 1.0, 0}
+DistortionK = {1.0, 0.22, 0.24, 0}
+Scale = {0.25, 0.5*AspectRatio, 0, 0}
+ScaleIn = {4.0, 2/AspectRatio, 0, 0}
+Left Screen Center = {0.25, 0.5, 0, 0}
+Left Lens Center = {0.287994117, 0.5, 0, 0}
+Right Screen Center = {0.75, 0.5, 0, 0}
+Right Lens Center = {0.712005913, 0.5, 0, 0}
+*/
+
+// Scales input texture coordinates for distortion.
+vec2 HmdWarp(vec2 in01, vec2 LensCenter)
+{
+    vec2 theta = (in01 - LensCenter)*ScaleIn; // Scales to [-1, 1]
+    float rSq = theta.x*theta.x + theta.y*theta.y;
+    vec2 rvector = theta*(HmdWarpParam.x + HmdWarpParam.y*rSq + HmdWarpParam.z*rSq*rSq + HmdWarpParam.w*rSq*rSq*rSq);
+
+    return LensCenter + Scale*rvector;
+}
+
+void main()
+{
+    // SOURCE: http://www.mtbs3d.com/phpbb/viewtopic.php?f=140&t=17081
+    
+    // The following two variables need to be set per eye
+    vec2 LensCenter = gl_FragCoord.x < 540 ? LeftLensCenter : RightLensCenter;
+    vec2 ScreenCenter = gl_FragCoord.x < 540 ? LeftScreenCenter : RightScreenCenter;
+
+    vec2 tc = HmdWarp(fragTexCoord, LensCenter);
+
+    if (any(bvec2(clamp(tc,ScreenCenter-vec2(0.25,0.5), ScreenCenter+vec2(0.25,0.5)) - tc))) finalColor = vec4(0.0, 0.0, 0.0, 1.0);
+    else
+    {
+        //tc.x = gl_FragCoord.x < 640 ? (2.0 * tc.x) : (2.0 * (tc.x - 0.5));
+        finalColor = texture2D(texture0, tc);
+    }
+}