Non kernel functions in compute shaders

Hello,
im currently starting with compute shaders and encountered following problem.

As the following code is not working, how to use functions that dont have a

#pragma kernel

inside a shader?

When adding the Add part directly to the ParticleUpdate function it does work.

(This is dummy code to show my problem)

Code (csharp):

1.  
2. #pragma kernel ParticleUpdate
3.  
4. struct Particle {
5. float3 color;
6. float3 position;
7. }
8.  
9. RWStructuredBuffer<Particle> _particles;
10.  
11. float Add(float a, float b) {
12. return a + b;
13. }
14.  
15. [numthreads(1024,1,1)]
16. void ParticleUpdate (uint3 id : SV_DispatchThreadID) {
17. _particles[id.x].color.x = Add(_particles[id.x].color.x, 1);
18. }

Edit: changed x to b in Add

 

Oh thats a typo from reducing the function to a more readable form. sry
x has to be b.

Whats not working is the function call with Add. The shader does not execute with it written like that, but if I do the same addition in ParticleUpdate directly it does execute.

Edit: Oh wow. I fixed my problem when converting it into the here posted code. So this does now work.

 

What i still find confusing is when i change my code to

Code (CSharp):

1.  
2. #pragma kernel ParticleUpdate
3.  
4. struct Particle {
5.     float3 position;
6.     float3 velocity;
7.     };
8.  
9. RWStructuredBuffer<Particle> _particles;
10. uniform float _deltaTime;
11.  
12. void Move(Particle particle) {
13.     particle.position += float3(1, 0, 0) * _deltaTime;
14. }
15.  
16. [numthreads(1024,1,1)]
17. void ParticleUpdate (uint3 id : SV_DispatchThreadID)
18. {
19.     Move(_particles[id.x]);
20. }

nothing happens.

 

Oh, I see. I assumed that the parameters are passed by reference instead of value.
Thanks for helping me out.

 

You can add

inout

before a parameter to pass it by reference.