[SOLVED] How to do this visual effect?

[XHH]

I was watching this video of a game named Chroma:


There's a very cool wave effect at 0:08 and I was wondering if this can be done in Love2D.

[raidho36]

Given that löve2d has shaders, everything is possible.

This is, I suppose, some sort of post-effect or something. It would, depending on pixel position relative to wave epicenter, sample texture (already rendered plain image) from a different point, closer or further than it actually would be, thus creating a warp effect.

If you don't know what shaders are and how to use them, I really suggest studying on that first before getting to do it.

[RedHot]

Instead of preaching generic and useless info I will try to get to the core.

Draw every frame to canvas, send canvas to a shader. Since Love2d doesn't provide a straight-forward access to Vertex Shader you can use the Fragment Shader called "Effect" in Love2d. In this very effect, use function called "Texel" when returning the pixel. It allows warping.

If you are a newbie that just wants the code you might get lucky cause I'm in the mood to share. Just give me some time to get my groceries

[T-Bone]

Is it really necessary to render to a Canvas? Couldn't you just apply the shader directly?

I always thought you could use the "texture Image" argument to the main function in the shader to access different parts of what you're drawing. It doesn't seem to work now when I try it though.

[raidho36]

No, you can't do it that way, it needs to be post-processed.

I always thought you could use the "texture Image" argument to the main function in the shader to access different parts of what you're drawing.

That's correct. Just keep in mind that "what you're drawing" is your plain sprite, period. Nothing more than that.

[T-Bone]

No, you can't do it that way, it needs to be post-processed.

I always thought you could use the "texture Image" argument to the main function in the shader to access different parts of what you're drawing.

That's correct. Just keep in mind that "what you're drawing" is your plain sprite, period. Nothing more than that.

Oh, of course the shader is applied while you're drawing of course, not afterwards. Now everything makes sense.

[XHH]

I've done some basic stuff with shaders like inverting colors. So where can I find sample code demonstrating a warp effect?

[retrotails]

I've done some basic stuff with shaders like inverting colors. So where can I find sample code demonstrating a warp effect?

edit: Here's my example. Use arrow keys to adjust properties.

[Bobbias]

Oh cool. I haven't messed around with shaders yet, so this'll be a good example to take a look at when I do.

[XHH]

edit: Here's my example. Use arrow keys to adjust properties.

Thank you so much! Can't wait to start using this!