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Comment by pizzafeelsright | Hacker News Reader

I am very curious how the physics feel realy-wordly for the most part at the mathematical level. Are there existing algos that define the gravitational pull of the "Facts" spots or was there a lot of tweaking?

The 45 degree rotation does require more dual input than I care for which makes me wonder if that is a design choice.

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The physics engine we are using is Rapier 3D which does a lot of the heavy lifting, even though we had to tweak a lot the physics properties of the ball and surfaces in order to get something that felt right. For hotspots specifically, we implemented the magnet-like effect with custom code (by applying a force that pushes the ball toward the center and slowing it down at the same time) as there is no attractor primitive in Rapier.

The dual input is indeed a consequence of our isometric-view design choice, which I agree may not be the easiest way to control the ball. But the 45 degree angle just looks cooler in our opinion.

> The 45 degree rotation does require more dual input than I care for which makes me wonder if that is a design choice.

Well they say "A Marble Madness-inspired WebGL game" so there is not much choice about the rotation [1]

[1] https://en.wikipedia.org/wiki/Marble_Madness

The NES Marble Madness port (and probably others) had a choice of control schemes, where the D-Pad is either mapped directly to the screen (Down is down) or mapped at a 45 degree angle (Down is down-right). I never could wrap my head around the latter, but I can see the benefit given the stage layout mostly uses 45 degree paths.

The second scheme works pretty well if you can turn the controller 45º. I never had an NES but I am pretty sure some of the isometric games I played on the c64 and Amiga had this as an option.

Looking through the linked docs I see the physics frameworks.

Of all the programming I find the 3D gaming to be the most complex and unattainable at my current knowledge or intelligence level.

FWIW, you can mentally remap the keys to partially eliminate dual input. E.g. Pressing down and right together as a single input moves the marble southeast. This considerably simplifies game play for me.

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