54 lines
1.0 KiB
JavaScript
54 lines
1.0 KiB
JavaScript
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const Container = require("./Container");
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const math = require("./utilities/math");
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class Camera extends Container {
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constructor(subject, viewport, worldSize = viewport) {
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super();
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this.w = viewport.w;
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this.h = viewport.h;
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this.worldSize = worldSize;
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this.setSubject(subject);
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}
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setSubject(e) {
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this.subject = e ? e.pos || e : this.pos;
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this.offset = { x: 0, y: 0 };
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// Center on the entity
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if (e && e.w) {
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this.offset.x += e.w / 2;
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this.offset.y += e.h / 2;
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}
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if (e && e.anchor) {
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this.offset.x -= e.anchor.x;
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this.offset.y -= e.anchor.y;
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}
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this.focus();
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}
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focus() {
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const { pos, w, h, worldSize, subject, offset } = this;
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const centeredX = subject.x + offset.x - w / 2;
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const maxX = worldSize.w - w;
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const x = -math.clamp(centeredX, 0, maxX);
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const centeredY = subject.y + offset.y - h / 2;
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const maxY = worldSize.h - h;
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const y = -math.clamp(centeredY, 0, maxY);
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pos.x = x;
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pos.y = y;
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}
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update(dt, t) {
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super.update(dt, t);
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if (this.subject) {
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this.focus();
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}
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}
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}
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module.exports = Camera;
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