Using a constant Array in Burst.

So i am in having a little of a problem with burst that i still didn't find a solution.
This is a simplified version of my current problem, the code have more stuff that is unrelated to the problem:

In my burst i am using a NativeArray<MyStruct>:

Code (CSharp):

1. public struct MyStruct{
2.         public enum Types{
3.             UseMatrix1, UseMatrix2, UseMatrix3
4.         }
5.  
6.         public Types myMatrix;
7.     }

Inside the Job(Burst).Execute() there is a switch(myMatrix), in all cases it will use a array of length = 9. Here are my arrays:

Code (CSharp):

1. public static readonly float[] Matrix1= {
2.             -1, -1, -1,
3.              -1, 9, -1,
4.              -1, -1, -1 };
5.  
6.         public static readonly float[] Matrix2= {
7.             -1, -1, -1,
8.              -1, 8, -1,
9.              -1, -1, -1 };
10.  
11.         public static readonly float[] Matrix3= {
12.             .2f, .25f, .2f,
13.              .25f, 0, .25f,
14.              .2f, .125f, .2f};

If i call the matrix inside the burst, it works! But it feel wrong since i am using static variables.

If inside of MyStruct is used a NativeArray<float> for the matrix, MyStruct becomes non blittable.
And if set the array as fixed, i will need to set the struct as unsafe, so I prefer to not do this.



The only other solution i could think of is creating a struct like:

Code (CSharp):

1. float a1, a2, a3;
2. float b1, b2, b3;
3. float c1, c2, c3;

And creating functions to get the index, but this still look like a hack. Just wondering if I am missing something obvious for this simple problem?

 

use float3x3 from

Unity.Mathematics

?

 

Well, i feel stupid now. Thanks M_R. It was such a simple solution.

 

I know this is old, but is there a way to do this for arrays of a compile-time constant length? For example, I'd like to precompute some values like this...

Code (CSharp):

1. const int TESSELATION = 25;
2. private static readonly float2[] arcCosSin = computeArcCosSin();
3. private static float2[] computeArcCosSin()
4. {
5.     float2[] result = new float2[TESSELATION];
6.     for(int i = 0; i < TESSELATION; ++i)
7.     {
8.         math.sincos(i * 1f / (TESSELATION - 1) * math.PI/2, out float s, out float c);
9.         result[i] = new float2(c, s);
10.     }
11.     return result;
12. }

Then I can change the

TESSELATION

and the array will update. But the whole array is essentially a compile-time constant.

(I guess I can use NativeArray with Allocator.Persistent and then make the caller know about this implementation detail, or I hardcode the values. Neither one is acceptable, IMO, especially if the use case is more advanced than just this).

 

Is something like this helpful?
https://docs.unity.cn/Packages/com....Unity.Collections.AllocatorManager.Range.html

I hope so, as you've been a HUGE help with your sermon on shader variants! Thank you!!!

 

Oh good idea ! I was using the FixedLists in jobs, but hadn't thought to pass them as constants.

 

I suspect they've created Blocks as a collection type that's pointer friendly for animation curves to be easily LUT'd... if/when they get around to making a DOTS animation system