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A comment on How does your programming language handle “minus zero” (-0.0)?. Parent comment

Re:How does your programming language handle “minus zero” (-... by scrooched_moose on Friday March 05, 2021 @10:34AM (#26357953)
Isn't that what caused the PS1 graphics "wobble"? I remember you could just stare at a wall, rotate the camera, and the textures would slightly jitter and move. It's really obvious in some the Metal Gear cutscenes, especially this conversation with Donald Anderson where the camera pans up from the floor (at 15m) or the sweep(15m31s):

https://www.youtube.com/watch?v=VLTqIXZ1jQQ#t=15m00s

I never had a PS1 but it always bugged me when playing on someone elses.

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Re:How does your programming language handle “minus zero” (-... by coopierez on Friday March 05, 2021 @11:04AM (#26358325)
This is because of two things: the affine texture mapping was incorrect, and there was no sub-pixel precision. The sub-pixel part is kinda float-related (though you could make use of fixed point too).
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Re:How does your programming language handle “minus zero” (-... by codetrotter on Friday March 05, 2021 @11:00AM (#26358280)
> I never had a PS1 but it always bugged me when playing on someone elses.

Conversely I like the fact a lot that it does. And some others that probably have fond memories of PS1 too recreated this on modern computers using shaders.

https://github.com/dsoft20/psx_retroshader

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Re:How does your programming language handle “minus zero” (-... by quelsolaar on Friday March 05, 2021 @11:15AM (#26358471)
yes, and the PS1 had a vector unit built in to the CPU that was used for world transform and it was only 24 bits.

Early PS1 games fit the entire world in to a 24 bit space, and you can tell that there is steping if you drive very slow in a game like Ridge Racer. Later games moved the world around in the coordinate system to manage precision.

Another reason why the graphics looks extra "popy" on PS1 (And early DirectX games) is that vertices where computed at a pixel accuracy. OpenGL, Doom, Quake and more modern hardware have sub pixel accuracy.

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Re:How does your programming language handle “minus zero” (-... by edflsafoiewq on Friday March 05, 2021 @11:53AM (#26358991)
No. The DS uses only fixed point numbers and does not wobble.
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