Schnitzel 0 Posted October 3, 2017 Report Share Posted October 3, 2017 Not sure if here's the best place for this but since it is not a bug etc I avoided opening an issue on github I stumbled upon some odd rotation code in phaser while reading https://phaser.io/tutorials/advanced-rendering-tutorial/part7 From src/pixi/renderers/webgl/utils/WebGLSpriteBatch.js and src/pixi/display/Sprite.js // Rotate matrix by 90 degrees // We use precalculated values for sine and cosine of rad(90) a = a0 * 6.123233995736766e-17 + -c0; b = b0 * 6.123233995736766e-17 + -d0; c = a0 + c0 * 6.123233995736766e-17; d = b0 + d0 * 6.123233995736766e-17; Ok. Some rotationcode with fancy precalculated values. But: the value given in e-notation is 0.00000000000000006123233995736766 and therefore effectively zero. Which makes sense since this was meant to be the precalculation of cos(rad(90)) - which equals exactly to zero. I suppose the literal resulted from a rounding error when someone typed Math.cos(Math.radians(90)) into a console So a better version would be: // Rotate matrix by 90 degrees a = -c0; b = -d0; c = a0; d = b0; Maybe someone sees this and is willing to fix it on the side... Quote Link to post Share on other sites

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