141 lines
3.4 KiB
GLSL
141 lines
3.4 KiB
GLSL
/*
|
|
* Copyright (c)2012 Adobe Systems Incorporated. All rights reserved.
|
|
* Copyright (c)2012 Branislav Ulicny
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
precision mediump float;
|
|
|
|
// Built-in attributes
|
|
|
|
attribute vec4 a_position;
|
|
attribute vec2 a_texCoord;
|
|
attribute vec3 a_triangleCoord;
|
|
|
|
// Built-in uniforms
|
|
|
|
uniform mat4 u_projectionMatrix;
|
|
uniform vec2 u_meshSize;
|
|
uniform vec2 u_textureSize;
|
|
|
|
// Uniform passed in from CSS
|
|
|
|
uniform mat4 transform;
|
|
uniform float amount;
|
|
uniform float randomness;
|
|
uniform vec3 flipAxis;
|
|
|
|
// Varyings
|
|
|
|
varying float v_depth;
|
|
varying vec2 v_uv;
|
|
|
|
// Constants
|
|
|
|
const float PI2 = 1.5707963267948966;
|
|
|
|
// Create perspective matrix
|
|
|
|
mat4 perspectiveMatrix(float p)
|
|
{
|
|
float perspective = - 1.0 / p;
|
|
return mat4(
|
|
1.0, 0.0, 0.0, 0.0,
|
|
0.0, 1.0, 0.0, 0.0,
|
|
0.0, 0.0, 1.0, perspective,
|
|
0.0, 0.0, 0.0, 1.0
|
|
);
|
|
}
|
|
|
|
// Rotate vector
|
|
|
|
vec3 rotateVectorByQuaternion(vec3 v, vec4 q)
|
|
{
|
|
vec3 dest = vec3(0.0);
|
|
|
|
float x = v.x, y = v.y, z = v.z;
|
|
float qx = q.x, qy = q.y, qz = q.z, qw = q.w;
|
|
|
|
// Calculate quaternion * vector.
|
|
|
|
float ix = qw * x + qy * z - qz * y,
|
|
iy = qw * y + qz * x - qx * z,
|
|
iz = qw * z + qx * y - qy * x,
|
|
iw = -qx * x - qy * y - qz * z;
|
|
|
|
// Calculate result * inverse quaternion.
|
|
|
|
dest.x = ix * qw + iw * -qx + iy * -qz - iz * -qy;
|
|
dest.y = iy * qw + iw * -qy + iz * -qx - ix * -qz;
|
|
dest.z = iz * qw + iw * -qz + ix * -qy - iy * -qx;
|
|
|
|
return dest;
|
|
}
|
|
|
|
// Convert rotation.
|
|
|
|
vec4 axisAngleToQuaternion(vec3 axis, float angle)
|
|
{
|
|
vec4 dest = vec4(0.0);
|
|
|
|
float halfAngle = angle / 2.0;
|
|
float s = sin(halfAngle);
|
|
|
|
dest.x = axis.x * s;
|
|
dest.y = axis.y * s;
|
|
dest.z = axis.z * s;
|
|
dest.w = cos(halfAngle);
|
|
|
|
return dest;
|
|
}
|
|
|
|
// Random function based on the tile coordinate.
|
|
// This will return the same value for all the vertices in the same tile (i.e. two triangles).
|
|
|
|
float random(vec2 scale)
|
|
{
|
|
// Use the fragment position as a different seed per-pixel.
|
|
return fract(sin(dot(vec2(a_triangleCoord.x, a_triangleCoord.y), scale)) * 4000.0);
|
|
}
|
|
|
|
// Main
|
|
|
|
void main()
|
|
{
|
|
// FIXME: We must swap x and y as a workaround for:
|
|
// https://bugs.webkit.org/show_bug.cgi?id=96285
|
|
vec2 u_meshSize = u_meshSize.yx;
|
|
|
|
vec4 pos = a_position;
|
|
float aspect = u_textureSize.x / u_textureSize.y;
|
|
|
|
float cx = a_triangleCoord.x / u_meshSize.y - 0.5 + 0.5 / u_meshSize.y;
|
|
float cy = a_triangleCoord.y / u_meshSize.x - 0.5 + 0.5 / u_meshSize.x;
|
|
|
|
vec3 centroid = vec3(cx, cy, 0.0);
|
|
float r = random(vec2(10.0, 80.0));
|
|
float rr = mix(0.0, PI2, amount * (1.0 + randomness * r));
|
|
|
|
vec4 rotation = vec4(flipAxis, rr);
|
|
vec4 qRotation = axisAngleToQuaternion(normalize(rotation.xyz), rotation.w);
|
|
|
|
vec3 newPosition = rotateVectorByQuaternion((pos.xyz - centroid)* vec3(aspect, 1., 1.0), qRotation) * vec3(1.0 / aspect, 1.0, 1.0) + centroid;
|
|
pos.xyz = newPosition;
|
|
|
|
gl_Position = u_projectionMatrix * transform * pos;
|
|
|
|
// Pass varyings to the fragment shader.
|
|
v_depth = abs(rr)/ PI2;
|
|
v_uv = a_texCoord;
|
|
}
|