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snake.js
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snake.js
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var createGraph = require('./create-graph');
var CurveFactory = require('./curve-factory');
var EndlessCurve = require('./endless-curve');
var createCube = require('primitive-cube');
var createSphere = require('primitive-icosphere');
var vec3 = require('gl-matrix').vec3;
function Snake(poly, length, speed, radius, handleScale) {
// box = createCube(.5, 2.5, .25, 1, 1, 1);
box = createSphere(1);
box.positions.map(v => {
v[0] *= .5;
v[1] *= 2.;
v[2] *= .3;
});
box.normals.map(v => {
v[0] /= .5;
v[1] /= 2.;
v[2] /= .3;
vec3.normalize(v, v);
});
var N = 750;
var instances = Array(N).fill().map((_, i) => {
return i;
});
this.texturePoints = 100;
this.textureConf = {
width: this.texturePoints,
height: 1,
channels: 3,
mag: 'linear',
type: 'float'
};
this.positionTex = regl.texture(this.textureConf);
this.normalTex = regl.texture(this.textureConf);
this.tangentTex = regl.texture(this.textureConf);
var graph = createGraph(poly);
var curveFactory = new CurveFactory(graph, radius, handleScale);
this.curve = new EndlessCurve(curveFactory.nextCurve);
this.drawSnake = regl({
frag: `
precision mediump float;
varying vec3 vNormal;
void pR(inout vec2 p, float a) {
p = cos(a)*p + sin(a)*vec2(p.y, -p.x);
}
void main() {
vec3 n = vNormal;
pR(n.xz, -.7);
pR(n.yz, -.5);
gl_FragColor = vec4(n * .5 + .5, 1);
}
`,
vert: `
precision mediump float;
uniform mat4 proj;
uniform mat4 view;
uniform mat4 model;
uniform float instances;
uniform sampler2D positionTex;
uniform sampler2D normalTex;
uniform sampler2D tangentTex;
attribute vec3 position;
attribute vec3 normal;
attribute float instance;
varying vec3 vNormal;
void pR(inout vec2 p, float a) {
p = cos(a)*p + sin(a)*vec2(p.y, -p.x);
}
mat4 rotateX(float a) {
return mat4(
1, 0, 0, 0,
0, cos(a), -sin(a), 0,
0, sin(a), cos(a), 0,
0, 0, 0, 1
);
}
mat4 rotateY(float a) {
return mat4(
cos(a), 0, sin(a), 0,
0, 1, 0, 0,
-sin(a), 0, cos(a), 0,
0, 0, 0, 1
);
}
mat4 rotateZ(float a) {
return mat4(
cos(a), -sin(a), 0, 0,
sin(a), cos(a), 0, 0,
0, 0, 1, 0,
0, 0, 0, 1
);
}
void main () {
float tt = instance / instances;
vec3 iPosition = texture2D(positionTex, vec2(tt, 0)).xyz;
vec3 iNormal = texture2D(normalTex, vec2(tt, 0)).xyz;
vec3 iTangent = texture2D(tangentTex, vec2(tt, 0)).xyz;
vec3 n = iNormal * 2. - 1.;
vec3 t = iTangent * 2. - 1.;
vec3 b = cross(t, n);
mat4 iPositionMat = mat4(
1, 0, 0, iPosition.x,
0, 1, 0, iPosition.y,
0, 0, 1, iPosition.z,
0, 0, 0, 1
);
mat4 iRotationMat = mat4(
n.x, t.x, b.x, 0,
n.y, t.y, b.y, 0,
n.z, t.z, b.z, 0,
0, 0, 0, 1
);
float thick = pow(tt, 1.);
thick = smoothstep(0., .98, tt) - smoothstep(.98, 1., tt);
vec4 pos = vec4(position * mix(.2, 1., thick), 1);
float rot = tt * instances * .95;
pos.z += thick * .8;
pos.y -= 1.;
iRotationMat = rotateX(-.4 * thick) * rotateY(rot) * iRotationMat;
pos = pos * iRotationMat;
vNormal = (model * (vec4(normal, 0) * iRotationMat)).xyz;
pos = pos * iPositionMat;
pos = proj * view * model * pos;
gl_Position = pos;
}
`,
attributes: {
position: box.positions,
normal: box.normals,
instance: {
buffer: instances,
divisor: 1
}
},
elements: box.cells,
instances: N,
count: box.cells.length * 3,
uniforms: {
positionTex: this.positionTex,
normalTex: this.normalTex,
tangentTex: this.tangentTex,
instances: N
}
});
this.distance = 0;
this.len = length;
this.speed = speed;
}
Snake.prototype.draw = function(context) {
this.distance = context.time * this.speed;
this.curve.configureStartEnd(this.distance, this.len);
var position = [];
var normal = [];
var tangent = [];
for (var i = 0; i < this.texturePoints; i++) {
var basis = this.curve.getBasisAt(i / this.texturePoints);
position = position.concat(
basis.position.x,
basis.position.y,
basis.position.z
);
normal = normal.concat(
basis.normal.x * .5 + .5,
basis.normal.y * .5 + .5,
basis.normal.z * .5 + .5
);
tangent = tangent.concat(
basis.tangent.x * .5 + .5,
basis.tangent.y * .5 + .5,
basis.tangent.z * .5 + .5
);
}
this.textureConf.data = position;
this.positionTex(this.textureConf);
this.textureConf.data = normal;
this.normalTex(this.textureConf);
this.textureConf.data = tangent;
this.tangentTex(this.textureConf);
this.drawSnake();
}
module.exports = Snake;