How to pass an array to a shader?

Help
,
1

Godot Version

4.2.2

Question

I do I pass an array to a shader in godot? How do I modify arrays? I kinda need this.

2

as a uniform:

uniform float myValues[12];

https://www.khronos.org/opengl/wiki/Data_Type_(GLSL)#Arrays

1 Like
3

Right, But what if that just doesn’t work it just returns white for everything?
if I use the code (not real code just demonstrating that if I change the grid it return an failure)
uniform int array[300];
void fragment(){
array[15] = 1;
}

4

Pretty confident you aren’t to assign values to a uniform within a shader, don’t expect those values to save between frames or even shading stages at the very least. You could make it not a uniform by removing the qualifier.

Could you give a more concrete example of what you are hoping to do?

5

Falling sand.

6

I am pretty sure it works. Check out my Spectrum Analyzer shader where I use an array to pass frequency data to VU meters in the shader code: Spectrum Analyzer - Godot Shaders

Anyway, as gertkeno says, uniform parameters are read-only, and you aren’t supposed to change their values.

7

Ahhh, Alright, thanks.

8

You might have to learn a lot more about shaders before falling sand, it’s rather tricky and involves lower-level tech that’s at least somwhat supported in Godot i.e. compute shaders.

Here’s a game that’s entire selling point is doing it’s sandy physics on the GPU

On the other end Noita is popular and does everything CPU side.