Using multiple textures in one shader

[Lomacar]

Hello. I am trying to convert an old cellular automata simulation I wrote in Processing to WebGL. Your example here was the first/best one that I could find that made use of swapping or pingponging of textures, which is necessary for CA simulations on the GPU. I am trying to just replace your frag shader with mine.

The problem I have is that my CA is complex and requires two separate textures to hold all the information about a cell's state. I am not able to figure out your Igloo API and I know nothing about WebGL. In fact I barely remember what I did in Processing years ago. I am hoping that only a few lines of code need to be changed. I think I will ultimately need two 'front' textures and two 'back' textures or maybe I just need two uniform's like state and state2?

All the guts of my old CA are written in GLSL and at the top I have uniform sampler2D src_tex_unit0, src_tex_unit1; which is how the two textures are passed in. And I have out vec4 outState, outEnergy;, which is the corresponding output values for the shader.

[Lomacar]

I think I will be able to figure out how to do what I want from scratch using P5.js.

[skeeto]

In case you hadn't seen it, here's the article I wrote about how it works: A GPU Approach to Conway's Game of Life https://nullprogram.com/blog/2014/06/10/ And in a later project I extended this to a more complex automata that solves mazes: A GPU Approach to Path Finding https://nullprogram.com/blog/2014/06/22/ https://github.com/skeeto/webgl-path-solver Though that still just uses a single texture. If you need more than that, you'll have to bind another pair of textures to uniforms. That's mostly about repeating exactly what is already done with the "front" and "back" textures. These days I do wish I hadn't used Igloo for this since it's an extra layer of abstraction that makes it harder to reuse. I no longer use Igloo for that reason, and instead use WebGL directly. I originally wrote and used Igloo as a kind of crutch while I was getting the hang of OpenGL and WebGL.

[Lomacar]

Thanks for the reply. I have managed to figure things out with P5. Well, I got a test with multiple textures working. Still hooking up all the wires for my old Processing simulation to work...