Barrel distortion as parameter

data/shaders/multiview/viewdisplay.frag

@@ -2,6 +2,11 @@
 
 layout (binding = 1) uniform sampler2DArray samplerView;
 
+layout (binding = 0) uniform UBO 
+{
+	layout(offset = 272) float distortionAlpha;
+} ubo;
+
 layout (location = 0) in vec2 inUV;
 layout (location = 0) out vec4 outColor;
 
@@ -9,7 +14,7 @@ layout (constant_id = 0) const float VIEW_LAYER = 0.0f;
 
 void main() 
 {
-	const float alpha = 0.2;
+	const float alpha = ubo.distortionAlpha;
 
 	vec2 p1 = vec2(2.0 * inUV - 1.0);
 	vec2 p2 = p1 / (1.0 - alpha * length(p1));