# Initialize array in glsl
**URL:** https://discourse.processing.org/t/initialize-array-in-glsl/6858
**Category:** Coding Questions
**Created:** [December 23, 2018, 9:32pm UTC](https://discourse.processing.org/t/initialize-array-in-glsl/6858 "2018-12-23T21:32:33Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@Stanlepunk](https://discourse.processing.org/u/Stanlepunk)
#### Post date: [December 23, 2018, 9:32pm UTC](https://discourse.processing.org/t/initialize-array-in-glsl/6858/1 "2018-12-23T21:32:33Z")
I want initialize an array from `uniform`, but the problem I cannot because the array must be init from `const`.
For this reason I must write a same method `n`twice, that’s make a lot of code to write the same thing.
is it possible ?
my problem :
```auto
const int p_2 = 2;
const int p_3 = 3;
const int p_4 = 4;
const int p_5 = 5;
const int p_6 = 6;
const int p_7 = 7;
const int p_8 = 8;
const int p_9 = 9;
vec3 palette_2() {
vec3 palette [p_2];
// rest of code
}
vec3 palette_3() {
vec3 palette [p_3];
// rest of code
}
vec3 palette_4() {
vec3 palette [p_4];
// rest of code
}
.../...
```
I want write something like
```auto
uniform int num;
vec3 palette(int num) {
vec3 palette [num];
}
```
---
### Author:  [@hamoid](https://discourse.processing.org/u/hamoid)
#### Post date: [December 23, 2018, 11:16pm UTC](https://discourse.processing.org/t/initialize-array-in-glsl/6858/2 "2018-12-23T23:16:38Z")
Hi! Your last example looks a bit odd, as the `palette` is duplicated as function name and variable and there’s no return in:
```auto
vec3 palette(int num) {
vec3 palette [num];
}
```
Maybe you want to have something like
```
const vec3 palette[3] = vec3[3](
vec3(0.0, 0.1, 0.2),
vec3(0.3, 0.1, 0.2),
vec3(0.5, 0.1, 0.2)
);
```
and then access
```
palette[index]
```
to get a color? Is that the goal?
But consider [possible issues](https://stackoverflow.com/questions/8338467/glsl-why-is-const-int-array-so-much-slower-than-normal-array) and [these too](https://stackoverflow.com/questions/10467110/how-to-define-constant-array-in-glsl-opengl-es-2-0) (in case it doesn’t work, or if you want to distribute your program).
---
### Author:  [@Stanlepunk](https://discourse.processing.org/u/Stanlepunk)
#### Post date: [December 24, 2018, 9:49am UTC](https://discourse.processing.org/t/initialize-array-in-glsl/6858/3 "2018-12-24T09:49:22Z")
Sure, I write where is my problem, the reason why there is no return 🙂
to see the full code is here [https://github.com/StanLepunK/Filter/blob/master/filters/shader/pixel.glsl](https://github.com/StanLepunK/Filter/blob/master/filters/shader/pixel.glsl)
I need if it’s possible only one method, here i can init the array palette with a uniform, or may be change the array size at each frame. Because in my architectory if I want change the size of the palette I need to copy the method for each size of palette, because I need a const in the method. I hope my problem is better understandable ?
---
### Author:  [@hamoid](https://discourse.processing.org/u/hamoid)
#### Post date: [December 24, 2018, 1:27pm UTC](https://discourse.processing.org/t/initialize-array-in-glsl/6858/4 "2018-12-24T13:27:14Z")
Why not make an array of the maximum size you will ever need, and then only use the number of elements needed on the current case?
For example, if you never need more than 32 items, then `vec3 palette[32] = vec3[32];` and if on the current frame you only need 5 items, then iterate over 5 items and assign values to them. Would that work?
To me it sounds not ideal to make an array of different size on every frame, better to keep the array of fixed size and then only use as much of it as you need.
Looking at the palette\_4 example, I think it could be written even without using an array and with only one for loop, as if you find the right color a break is triggered, which means it was not necessary to calculate the remaining colors. But maybe other palette\_X cases do need an array?
---
### Author:  [@Stanlepunk](https://discourse.processing.org/u/Stanlepunk)
#### Post date: [December 24, 2018, 1:46pm UTC](https://discourse.processing.org/t/initialize-array-in-glsl/6858/5 "2018-12-24T13:46:15Z")
“Elementary, my dear Watson”… why I don’t think about that soon. Thx a lot for your simple and GREAAATTTT idea. Best for X-mass my dear Hamoid !