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Contents
// Inspired by the "Angular Fisheye à la Bourke" sketch from
// Jonathan Cremieux, as shown in the OpenProcessing website:
// http://openprocessing.org/visuals/?visualID=12140
// Using the inverse transform of the angular fisheye as
// explained in Paul Bourke's website:
// http://paulbourke.net/miscellaneous/domefisheye/fisheye/
#ifdef GL_ES
precision mediump float;
precision mediump int;
#endif
#define PROCESSING_TEXTURE_SHADER
uniform sampler2D texture;
uniform mat4 texMatrix;
varying vec4 vertColor;
varying vec4 vertTexCoord;
uniform float aperture;
const float PI = 3.1415926535;
void main(void) {
float apertureHalf = 0.5 * aperture * (PI / 180.0);
// This factor ajusts the coordinates in the case that
// the aperture angle is less than 180 degrees, in which
// case the area displayed is not the entire half-sphere.
float maxFactor = sin(apertureHalf);
// The st factor takes into account the situation when non-pot
// textures are not supported, so that the maximum texture
// coordinate to cover the entire image might not be 1.
vec2 stFactor = vec2(1.0 / abs(texMatrix[0][0]), 1.0 / abs(texMatrix[1][1]));
vec2 pos = (2.0 * vertTexCoord.st * stFactor - 1.0);
float l = length(pos);
if (l > 1.0) {
gl_FragColor = vec4(0, 0, 0, 1);
} else {
float x = maxFactor * pos.x;
float y = maxFactor * pos.y;
float n = length(vec2(x, y));
float z = sqrt(1.0 - n * n);
float r = atan(n, z) / PI;
float phi = atan(y, x);
float u = r * cos(phi) + 0.5;
float v = r * sin(phi) + 0.5;
gl_FragColor = texture2D(texture, vec2(u, v) / stFactor) * vertColor;
}
}
Version data entries
8 entries across 8 versions & 1 rubygems