How much faster is it to render just the parts of the canvas that changed, compared to the whole thing?
Rendering a white dot that moves across a black background.
<canvas id="c" width="640" height="480">
var canvas = document.getElementById('c');
var context = canvas.getContext('2d');
var HEIGHT = 100;
Preparation code output
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re-render whole scene (black rect)
only render differences
re-render whole scene (clear rect)
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