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game.graphics = (
(context) => {
context.imageSmoothingEnabled = false;
const clear = () => {
context.clearRect(0, 0, game.width, game.height);
};
const Sprite = ({sheetSrc, spriteX, spriteY, spriteWidth, spriteHeight, timePerFrame, cols, rows, numFrames, drawFunction}) => {
timePerFrame = timePerFrame ?? 100;
numFrames = numFrames ?? 1;
cols = cols ?? numFrames;
rows = rows ?? 1;
let ready = false;
let image;
if (sheetSrc) {
image = new Image();
image.src = sheetSrc;
image.onload = () => { ready = true; };
}
let currentFrame = 0;
let lastTime = performance.now();
let draw;
if (!drawFunction) {
draw = (_elapsedTime, {x, y, rot, width, height}) => {
if (ready) {
if (numFrames > 1) {
if (performance.now()-lastTime > timePerFrame) {
lastTime = performance.now();
currentFrame = (currentFrame + 1) % numFrames;
}
}
context.save();
context.translate(x+width/2, y+height/2);
context.rotate(rot * Math.PI / 180);
context.translate(-x-width/2, -y-height/2);
const row = currentFrame % rows;
const col = Math.floor(currentFrame / rows);
context.drawImage(image, spriteX+col*spriteWidth, spriteY+row*spriteHeight, spriteWidth, spriteHeight, x, y, width, height);
context.restore();
}
};
} else {
draw = (elapsedTime, drawSpec) => drawFunction(elapsedTime, drawSpec, context);
}
return { draw, timePerFrame, numFrames };
}
return { clear, Sprite };
}
)(document.getElementById("game-canvas").getContext("2d"));
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