perfect-postcode/frontend/src/lib/PieHexExtension.ts

137 lines
3.7 KiB
TypeScript

/* eslint-disable @typescript-eslint/no-explicit-any */
import { LayerExtension } from '@deck.gl/core';
import { ENUM_PALETTE } from './consts';
/**
* LayerExtension that turns polygon fills into pie charts.
*
* Follows the canonical deck.gl v9 extension pattern:
* - defaultProps with type:'accessor' enables getSubLayerProps() to wrap
* accessors via getSubLayerAccessor(), which unwraps __source.object to
* access the original data item through CompositeLayer sublayer chains.
* - stepMode:'dynamic' handles per-instance counting automatically.
* - isEnabled() restricts to SolidPolygonLayer (fill) sublayers only.
*
* Accepts an optional custom palette in the constructor for per-feature color overrides.
*/
function paletteToGlsl(palette: [number, number, number][]): string {
return palette
.map(
(c) =>
`vec3(${(c[0] / 255).toFixed(4)}, ${(c[1] / 255).toFixed(4)}, ${(c[2] / 255).toFixed(4)})`
)
.join(',\n ');
}
export class PieHexExtension extends LayerExtension {
static extensionName = 'PieHexExtension';
static defaultProps = {
getCenter: { type: 'accessor', value: [0, 0] },
getRatios0: { type: 'accessor', value: [1, 0, 0, 0] },
getRatios1: { type: 'accessor', value: [0, 0, 0, 0] },
getRatios2: { type: 'accessor', value: [0, 0] },
};
private paletteGlsl: string;
constructor(palette?: [number, number, number][]) {
super();
this.paletteGlsl = paletteToGlsl(palette ?? ENUM_PALETTE);
}
isEnabled(layer: any): boolean {
return layer.id.endsWith('-fill');
}
getShaders(this: any, extension: any): any {
if (!extension.isEnabled(this)) return null;
return {
modules: [
{
name: 'pieHex',
inject: {
'vs:#decl': `\
in vec2 instancePieCenter;
in vec4 instanceRatios0;
in vec4 instanceRatios1;
in vec2 instanceRatios2;
out vec2 vPieCenter;
out vec2 vPieFragPos;
out vec4 vRatios0;
out vec4 vRatios1;
out vec2 vRatios2;`,
'vs:#main-end': `\
vPieCenter = project_position(vec3(instancePieCenter, 0.0)).xy;
vPieFragPos = geometry.position.xy;
vRatios0 = instanceRatios0;
vRatios1 = instanceRatios1;
vRatios2 = instanceRatios2;`,
'fs:#decl': `\
in vec2 vPieCenter;
in vec2 vPieFragPos;
in vec4 vRatios0;
in vec4 vRatios1;
in vec2 vRatios2;
const vec3 pieColors[10] = vec3[10](
${extension.paletteGlsl}
);`,
'fs:DECKGL_FILTER_COLOR': `\
{
vec2 delta = vPieFragPos - vPieCenter;
float angle = atan(delta.x, -delta.y) / (2.0 * 3.14159265) + 0.5;
float ratios[10];
ratios[0] = vRatios0.x; ratios[1] = vRatios0.y;
ratios[2] = vRatios0.z; ratios[3] = vRatios0.w;
ratios[4] = vRatios1.x; ratios[5] = vRatios1.y;
ratios[6] = vRatios1.z; ratios[7] = vRatios1.w;
ratios[8] = vRatios2.x; ratios[9] = vRatios2.y;
float cumulative = 0.0;
vec3 sliceColor = pieColors[0];
for (int i = 0; i < 10; i++) {
cumulative += ratios[i];
if (angle < cumulative) {
sliceColor = pieColors[i];
break;
}
}
color = vec4(sliceColor, 1.0);
}`,
},
uniformTypes: {},
},
],
};
}
initializeState(this: any, _context: any, extension: any): void {
if (!extension.isEnabled(this)) return;
const am = this.getAttributeManager();
if (!am) return;
am.add({
instancePieCenter: {
size: 2,
stepMode: 'dynamic',
accessor: 'getCenter',
},
instanceRatios0: {
size: 4,
stepMode: 'dynamic',
accessor: 'getRatios0',
},
instanceRatios1: {
size: 4,
stepMode: 'dynamic',
accessor: 'getRatios1',
},
instanceRatios2: {
size: 2,
stepMode: 'dynamic',
accessor: 'getRatios2',
},
});
}
}