sdf-2d/src/drawables/shapes/droplet-factory.ts

100 lines
3 KiB
TypeScript

import { mat2d, vec2, vec3, vec4 } from 'gl-matrix';
import { clamp01 } from '../../helper/clamp';
import { codeForColorAccess } from '../../helper/code-for-color-access';
import { mix } from '../../helper/mix';
import { DrawableDescriptor } from '../drawable-descriptor';
import { EmptyDrawable } from '../empty-drawable';
/**
* @category Drawable
*/
class DropletBase extends EmptyDrawable {
constructor(
public readonly from: vec2,
public readonly to: vec2,
public readonly fromRadius: number,
public readonly toRadius: number
) {
super();
}
}
/**
* @category Drawable
*/
export const DropletFactory = (color: vec3 | vec4 | number): typeof DropletBase => {
class Droplet extends DropletBase {
public static descriptor: DrawableDescriptor = {
sdf: {
shader: `
uniform vec2 froms[DROPLET_COUNT];
uniform vec2 toFromDeltas[DROPLET_COUNT];
uniform float fromRadii[DROPLET_COUNT];
uniform float toRadii[DROPLET_COUNT];
float dropletMinDistance(vec2 target, out vec4 color) {
color = ${codeForColorAccess(color)};
float minDistance = 1000.0;
for (int i = 0; i < DROPLET_COUNT; i++) {
vec2 targetFromDelta = target - froms[i];
float h = clamp(
dot(targetFromDelta, toFromDeltas[i])
/ max(dot(toFromDeltas[i], toFromDeltas[i]), 0.00000001),
0.0, 1.0
);
float currentDistance = -mix(
fromRadii[i], toRadii[i], h
) + distance(
targetFromDelta, toFromDeltas[i] * h
);
minDistance = min(minDistance, currentDistance);
}
return minDistance;
}
`,
distanceFunctionName: 'dropletMinDistance',
},
propertyUniformMapping: {
from: 'froms',
toFromDelta: 'toFromDeltas',
fromRadius: 'fromRadii',
toRadius: 'toRadii',
},
uniformCountMacroName: 'DROPLET_COUNT',
shaderCombinationSteps: [0, 1, 4, 16, 32],
empty: new Droplet(vec2.create(), vec2.create(), 0, 0),
};
public minDistance(target: vec2): number {
const toFromDelta = vec2.subtract(vec2.create(), this.to, this.from);
const targetFromDelta = vec2.subtract(vec2.create(), target, this.from);
const h = clamp01(
vec2.dot(targetFromDelta, toFromDelta) / vec2.dot(toFromDelta, toFromDelta)
);
return (
vec2.distance(targetFromDelta, vec2.scale(vec2.create(), toFromDelta, h)) -
mix(this.fromRadius, this.toRadius, h)
);
}
protected getObjectToSerialize(transform2d: mat2d, transform1d: number): any {
const toFromDelta = vec2.subtract(vec2.create(), this.to, this.from);
return {
from: vec2.transformMat2d(vec2.create(), this.from, transform2d),
toFromDelta: vec2.scale(vec2.create(), toFromDelta, transform1d),
fromRadius: this.fromRadius * transform1d,
toRadius: this.toRadius * transform1d,
};
}
}
return Droplet;
};