perspective.glsl
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uniform float ox;
uniform float oy;
uniform float rotation;
uniform bool isShort;
uniform float intensity;
uniform float angle;
uniform float prange;
uniform float progress;
uniform vec4 resolution;
uniform sampler2D src1;
uniform sampler2D src2;
varying vec2 vUv;
float pi = 3.141592653;
vec2 rotate(vec2 uv, vec2 mid, float rotation) {
return vec2(cos(rotation) * (uv.x - mid.x) + sin(rotation) * (uv.y - mid.y) + mid.x, cos(rotation) * (uv.y - mid.y) - sin(rotation) * (uv.x - mid.x) + mid.y);
}
float map(float a, float b, float c, float d, float v, float cmin, float cmax) {
return clamp((v - a) * (d - c) / (b - a) + c, cmin, cmax);
}
vec2 plane3d(vec2 uv, vec2 center, float xr, float yr) {
vec2 rd = vec2(uv.x, 0.);
vec2 a1 = vec2(0., -1.);
vec2 b1 = rd - a1;
vec2 c1 = rotate(vec2(-1., 0.), vec2(center.x, 0.), yr);
vec2 d1 = rotate(vec2(1., 0.), vec2(center.x, 0.), yr) - c1;
float u = ((c1.y + 1.) * d1.x - c1.x * d1.y) / (d1.x * b1.y - d1.y * b1.x);
float sx = u * b1.x;
float sy = u * uv.y;
rd = vec2(sy, 0.);
vec2 b2 = rd - a1;
vec2 c2 = rotate(vec2(-1., 0.), vec2(center.y, 0.), xr);
vec2 d2 = rotate(vec2(1., 0.), vec2(center.y, 0.), xr) - c2;
float v = ((c2.y + 1.) * d2.x - c2.x * d2.y) / (d2.x * b2.y - d2.y * b2.x);
return vec2(v * sx, v * b2.x);
}
vec2 rotatePlane(vec2 uv, vec2 o, float rx, float ry) {
uv = uv * 2. - 1.;
uv = plane3d(uv, o, rx, ry);
uv = (1. + uv) / 2.;
return uv;
}
float map(float a, float b, float c, float d, float v) {
return clamp((v - a) * (d - c) / (b - a) + c, 0., 1.);
}
vec2 mirror(vec2 v) {
vec2 m = mod(v, 2.0);
return mix(m, 2.0 - m, step(1.0, m));
}
vec2 zoom(vec2 uv, float p, float z) {
float m = sin(pi * pow(p, 1.));
if (z != 0.) {
uv.x -= 0.5;
uv.y -= 0.5;
uv *= (z * m + 1.);
uv.x += 0.5;
uv.y += 0.5;
}
return uv;
}
float quarticInOut(float t) {
return t < 0.5 ? +8.0 * pow(t, 4.0) : -8.0 * pow(t - 1.0, 4.0) + 1.0;
}
void main() {
vec2 uv = vUv;
float aspect = resolution.x / resolution.y;
vec2 origin = vec2(ox, oy);
float m = progress;
float nprog = map((0.5 - prange), (0.5 + prange), 0., 1., m, 0., 1.);
float tr = sin(pi * pow(map(0.0, .7, 0., 1., m), 2.));
float rm = map(0., 1., 0., 1., m);
rm = quarticInOut(rm);
float rx = tr * radians(intensity) * cos(angle);
float ry = tr * radians(intensity) * sin(angle);
uv = zoom(uv, 1. - rm, .5);
vec2 tUv = uv;
tUv = rotatePlane(tUv, origin, rx, ry);
origin.x *= aspect;
tUv.x *= aspect;
tUv = rotate(tUv, origin, rm * rotation);
tUv.x /= aspect;
vec2 tUvIn = tUv;
if (isShort) {
tUvIn.x -= origin.x / aspect * 2.;
tUvIn.y -= origin.y * 2.;
}
tUvIn = mirror(tUvIn);
vec2 nUv = tUv;
nUv = mirror(nUv);
gl_FragColor = mix(TEXTURE2D(src1, nUv), TEXTURE2D(src2, tUvIn), nprog);
}