michael/pathfinder
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pathfinder
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Detect square paths

This commit is contained in:
Patrick Walton 2018-11-16 15:34:01 -08:00
parent 8c1414e75d
commit bb8aa46c1a
1 changed files with 62 additions and 18 deletions
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80
demo2/pathfinder.ts
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@ -29,6 +29,8 @@ const QUAD_VERTEX_POSITIONS: Uint8Array = new Uint8Array([
0, 1,
]);
const EPSILON: number = 1e-6;
interface SVGPath {
abs(): SVGPath;
translate(x: number, y: number): SVGPath;
@ -37,9 +39,18 @@ interface SVGPath {
SVGPath;
}
interface Point2D {
class Point2D {
x: number;
y: number;
constructor(x: number, y: number) {
this.x = x;
this.y = y;
}
approxEq(other: Point2D): boolean {
return Math.abs(this.x - other.x) <= EPSILON && Math.abs(this.y - other.y) <= EPSILON;
}
}
interface Size2D {
@ -228,6 +239,9 @@ class App {
gl.enableVertexAttribArray(coverProgram.attributes.TileIndex);
gl.enableVertexAttribArray(coverProgram.attributes.Color);
// Set up event handlers.
this.canvas.addEventListener('click', event => this.onClick(event), false);
this.scene = null;
this.primitiveCount = 0;
}
@ -312,11 +326,12 @@ class App {
point = firstPoint;
} else {
point = {
x: parseFloat(segment[segment.length - 2]) - tile.origin.x,
y: parseFloat(segment[segment.length - 1]) - tile.origin.y,
x: parseFloat(segment[segment.length - 2]),
y: parseFloat(segment[segment.length - 1]),
};
}
/*
if (!(point.x > -1.0))
throw new Error("x too low");
if (!(point.y > -1.0))
@ -325,6 +340,7 @@ class App {
throw new Error("x too high:" + point.x);
if (!(point.y < TILE_SIZE + 1.0))
throw new Error("y too high");
*/
if (segment[0] === 'M') {
firstPoint = point;
@ -362,6 +378,10 @@ class App {
this.primitiveCount = primitiveCount;
console.log(primitiveCount + " primitives");
}
private onClick(event: MouseEvent): void {
this.redraw();
}
}
class Scene {
@ -420,13 +440,16 @@ class Scene {
let x = boundingRect.origin.x - boundingRect.origin.x % TILE_SIZE;
while (true) {
const tileBounds = {
origin: {x, y},
origin: new Point2D(x, y),
size: {width: TILE_SIZE, height: TILE_SIZE},
};
const tilePath = this.clipPathToRect(path, tileBounds);
if (tilePath.toString().length > 0)
tiles.push(new Tile(pathElementIndex, tilePath, tileBounds.origin));
if (tilePath.toString().length > 0) {
tilePath.translate(-tileBounds.origin.x, -tileBounds.origin.y);
if (!pathIsSquare(tilePath, TILE_SIZE))
tiles.push(new Tile(pathElementIndex, tilePath, tileBounds.origin));
}
if (x >= boundingRect.origin.x + boundingRect.size.width)
break;
@ -465,6 +488,7 @@ class Scene {
document.body.removeChild(svgElement);
console.log(tiles);
this.tiles = tiles;
this.pathColors = pathColors;
}
@ -483,8 +507,8 @@ class Scene {
}
});
if (minX == null || minY == null || maxX == null || maxY == null)
return {origin: {x: 0, y: 0}, size: {width: 0, height: 0}};
return {origin: {x: minX, y: minY}, size: {width: maxX - minX, height: maxY - minY}};
return {origin: new Point2D(0, 0), size: {width: 0, height: 0}};
return {origin: new Point2D(minX, minY), size: {width: maxX - minX, height: maxY - minY}};
}
private clipPathToRect(path: SVGPath, tileBounds: Rect): SVGPath {
@ -496,17 +520,15 @@ class Scene {
}
private clipPathToEdge(edge: Edge, edgePos: number, input: SVGPath): SVGPath {
let pathStart: Point2D | null = null, from = {x: 0, y: 0}, firstPoint = false;
let pathStart: Point2D | null = null, from = new Point2D(0, 0), firstPoint = false;
let output: string[][] = [];
input.iterate(segment => {
const event = segment[0];
let to;
switch (event) {
case 'M':
from = {
x: parseFloat(segment[segment.length - 2]),
y: parseFloat(segment[segment.length - 1]),
};
from = new Point2D(parseFloat(segment[segment.length - 2]),
parseFloat(segment[segment.length - 1]));
pathStart = from;
firstPoint = true;
return;
@ -516,10 +538,8 @@ class Scene {
to = pathStart;
break;
default:
to = {
x: parseFloat(segment[segment.length - 2]),
y: parseFloat(segment[segment.length - 1]),
};
to = new Point2D(parseFloat(segment[segment.length - 2]),
parseFloat(segment[segment.length - 1]));
break;
}
@ -586,7 +606,7 @@ class Scene {
}
const intersection = cross(cross(start, end), edgeVector);
return {x: intersection.x / intersection.z, y: intersection.y / intersection.z};
return new Point2D(intersection.x / intersection.z, intersection.y / intersection.z);
}
}
@ -687,6 +707,30 @@ function waitForQuery(gl: WebGL2RenderingContext, disjointTimerQueryExt: any, qu
console.log(elapsed + "ms elapsed");
}
function pathIsSquare(path: SVGPath, squareLength: number): boolean {
const SQUARE_VERTICES = [
new Point2D(0.0, 0.0),
new Point2D(0.0, squareLength),
new Point2D(squareLength, squareLength),
new Point2D(squareLength, 0.0),
];
let result = true;
path.iterate((segment, index) => {
if (index < SQUARE_VERTICES.length) {
const point = new Point2D(parseFloat(segment[1]), parseFloat(segment[2]));
result = result && point.approxEq(SQUARE_VERTICES[index]);
} else if (index === SQUARE_VERTICES.length) {
const point = new Point2D(parseFloat(segment[1]), parseFloat(segment[2]));
result = result && (segment[0] === 'Z' || point.approxEq(SQUARE_VERTICES[0]));
} else if (index === SQUARE_VERTICES.length + 1) {
result = result && segment[0] === 'Z';
} else {
result = false;
}
});
return result;
}
function main(): void {
window.fetch(SVG).then(svg => {
svg.text().then(svgText => {