LabyStudio
85 lines
2.1 KiB
JavaScript
85 lines
2.1 KiB
JavaScript
window.Timer = class {
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/**
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* Timer to control the tick speed independently of the framerate
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*
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* @param ticksPerSecond Amount of ticks per second
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*/
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constructor(ticksPerSecond) {
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this.MS_PER_SECOND = 1000;
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this.MAX_MS_PER_UPDATE = 1000;
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this.MAX_TICKS_PER_UPDATE = 100;
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/**
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* Amount of ticks per second
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*/
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this.ticksPerSecond = ticksPerSecond;
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/**
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* Last time updated in nano seconds
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*/
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this.lastTime = this._nanoTime();
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/**
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* Scale the tick speed
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*/
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this.timeScale = 1.0;
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/**
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* Framerate of the advanceTime update
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*/
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this.fps = 0.0;
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/**
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* Passed time since last game update
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*/
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this.passedTime = 0.0;
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/**
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* The amount of ticks for the current game update.
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* It's the passed time as an integer
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*/
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this.ticks = 0;
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/**
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* The overflow of the current tick, caused by casting the passed time to an integer
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*/
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this.partialTicks = 0;
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}
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/**
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* This function calculates the amount of ticks required to reach the ticksPerSecond.
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* Call this function in the main render loop of the game
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*/
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advanceTime() {
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let now = this._nanoTime();
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let passedMs = now - this.lastTime;
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// Store nano time of this update
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this.lastTime = now;
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// Maximum and minimum
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passedMs = Math.max(0, passedMs);
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passedMs = Math.min(this.MAX_MS_PER_UPDATE, passedMs);
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// Calculate fps
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this.fps = this.MS_PER_SECOND / passedMs;
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// Calculate passed time and ticks
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this.passedTime += passedMs * this.timeScale * this.ticksPerSecond / this.MS_PER_SECOND;
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this.ticks = parseInt(this.passedTime);
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// Maximum ticks per update
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this.ticks = Math.min(this.MAX_TICKS_PER_UPDATE, this.ticks);
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// Calculate the overflow of the current tick
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this.passedTime -= this.ticks;
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this.partialTicks = this.passedTime;
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}
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_nanoTime() {
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return Date.now();
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}
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}
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