Drawing Outlines in 3D - 3D Games in GameMaker Studio 2 - pusugames.com

Drawing Outlines in 3D – 3D Games in GameMaker Studio 2

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Drawing an outline around something in 3D is easier than you might expect, and works well enough in most cases. Here’s a simple but effective trick that games like Okami use!

As an added bonus, you can use a variation of this to get a silhouette effect.

This trick relies on smart use of the backface culling direction in order to work:

Here’s the code:

GameMaker 3D playlist:

GameMaker Studio 2 playlist:

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I’ve now made that Patreon:

That promised social media link spam.

Transition / idle music is by my old friend Kamex:

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  1. Hi nice work! I have a question. Is it possible to create a top down 3d world with caves and houses with multiple floors and an uneaven landscape? or is programming something like that not doable in game maker?

  2. Not sure what the performance hit would be like, but if you're worried about other objects occluding an outline, you could draw the outline to a surface and then draw that surface to a flat plane on the screen, lined up with the 3D object, with depth testing on. At least, this will work if I understand properly.

  3. My mom played the hell out of Okami but I never really got into it.

  4. Something that somebody reminded me that I didn't really give attention to in the video: simply scaling the model up wouldn't be enough for complicated objects. For something that isn't a uniform shape, you'd need to go to the extra work of selectively pushing vertices/faces outwards based on their normals – which may be a bit tedious, although the overall process wouldn't be any more complicated.
    Edit: I can't believe I didn't think of this before, but you could totally do this automatically by pushing vertex positions outward in the direction of the normals in the vertex shader.

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