Fix the camera rounding to work when following objects with even dimensions #3789
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…nsions instead of odd ones.
…stracted to sprite position.
4ian
approved these changes
Mar 31, 2022
| @@ -85,10 +85,10 @@ namespace gdjs { | |||
| // the sprite one and it changes in which direction sprites are rounded. | |||
| // It makes sprites rounding inconsistent with each other | |||
| // and they seems to move on pixel left and right. | |||
| this._pixiContainer.position.x = Math.round( | |||
| this._pixiContainer.position.x = Math.ceil( | |||
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Maybe add a link to this PR in the comment so that we can find the context back and why ceil was chosen.
D8H
commented
Mar 31, 2022
Comment on lines
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| // PIXI uses a floor function on sprites position on the screen, | ||
| // so a floor must be applied on the camera position too. | ||
| // According to the above calculus, | ||
| // _pixiContainer.position is the opposite of the camera, | ||
| // this is why the ceil function is used floor(x) = -ceil(-x). | ||
| // | ||
| // When the camera directly follows an object, | ||
| // given this object dimension is even, | ||
| // the decimal part of onScenePosition and cameraPosition are the same. | ||
| // | ||
| // Doing the calculus without rounding: | ||
| // onScreenPosition = onScenePosition - cameraPosition | ||
| // onScreenPosition = 980.75 - 200.75 | ||
| // onScreenPosition = 780 | ||
| // | ||
| // Doing the calculus with rounding: | ||
| // onScreenPosition = floor(onScenePosition + ceil(-cameraPosition)) | ||
| // onScreenPosition = floor(980.75 + ceil(-200.75)) | ||
| // onScreenPosition = floor(980.75 - 200) | ||
| // onScreenPosition = floor(780.75) | ||
| // onScreenPosition = 780 |
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I added this explanation.
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Excellent! Love this example, that's very clear now (notably the fact that there is a minus in the positioning, so ceil instead of floor).
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Thanks again for investigating this! |
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Fix the camera rounding to work when following objects with even dimensions instead of odd ones.
I actually used
ceilbecause otherwise, when the character jumps, it seems to move from one pixel on screen.Direct following
Linear following
There will be 2 alerts next to each other, but I think it's not an issue.