Create a float3 from a Matrix4x4

Hello.
I'm mainly using Amplify Shadder but for a specific effect I had to go into the code generated by the pluggin.

I was using from a script "SetVectorArray" to Update an array of positions in the Shader.
It worked but it was pretty heavy.
So I tried to replace that by using Matrix4x4 set to half to see if it was faster, but since I'm not used to code a shader directly I'm having trouble fixing it, here is the part causing me problems:

Spoiler: Code

Code (CSharp):

1.  
2. float3 pos1 = 0;
3. float3 pos2 = 0;
4. float3 pos3 = 0;
5. float3 pos4 = 0;
6.  
7. for (int i = 0; i < 4; i++)
8. {
9.    switch(i)
10.    {
11.    case 0:
12.        for (int u = 0; u < 3; u++)
13.            pos1[u] = PositionMatrix[i,u];
14.        break;
15.    case 1:
16.        for (int o = 0; o < 3; o++)
17.            pos2[o] = PositionMatrix[i,o];
18.        break;
19.    case 2:
20.        for (int p = 0; p < 3; p++)
21.            pos3[p] = PositionMatrix[i,p];
22.        break;
23.    case 3:
24.        for (int m = 0; m < 3; m++)
25.            pos4[m] = PositionMatrix[i,m];
26.        break;
27.    }
28. }
29. }

I want to save 4 positions sent by a script from this matrix, and then do stuff with it.
But it looks like every "pos" are the exact same even if I can clearly see in my script that I'm sending a matrix with different values inside.
I guess they are the same values because if I comment out every cases except one and test them one by one, they all display what I want at the first position when they should be displaying it the their respective positions..

If I take for exemple the first loop I tried to replace it by several things, listed bellow:

Code (CSharp):

1. case 0:
2.     pos1[u] = PositionMatrix[i][u];
3. break;
4. ----------------------------------------------------------------------------------------------------
5. case 0:
6.     pos1[u] = PositionMatrix.this[i,u];    //error: "invalid subscript 'this'"
7. break;
8. ----------------------------------------------------------------------------------------------------
9. //removing the loop:
10. case 0:
11.     pos1 = float3(PositionMatrix[0,0], PositionMatrix[1,0], PositionMatrix[2,0]);
12. break;
13. //but I get : "incorrect number of arguments to numeric-type constructor"

I've spend way too much time on this little thing and I don't even know if it'll give me any performance boost.
I just want to get those matrix4x4 floats and make float3 with them.
I hope you can help me.
Thank you.

 

Wow, an iterator in a switch in a interator. That's a lot of inefficient code to do what can be done with out any of that.

Here's the way to access elements of a matrix in HLSL:
https://docs.microsoft.com/en-us/wi...phics-hlsl-per-component-math#the-matrix-type

float3 pos0 = PositionMatrix._m00_m01_m02;
float3 pos1 = PositionMatrix._m10_m11_m12;
float3 pos2 = PositionMatrix._m20_m21_m22;
float3 pos3 = PositionMatrix._m30_m31_m32;

And done. Don’t do anything more. Just output those 4 values from your custom node and use them as needed. These are row-column indices, so make sure you're using matrix.SetRow() in c#.

Also it probably won’t have any affect on your performance.

 

Ok I looked into what you said and it worked.
I got way better performances but it was mostly because I re-made my c# code sending the matrix.
I was checking collisions on multiple objets to get serveral materials but that was not needed since I could set any global variable with Shader.SetGlobalMatrix();

I was using loops and a switch because in my head "loops go fast!" and I was desperate to go around some errors I was getting since it doesn't really work exactly the same as coding a regular code.
I'm self taught so I'm probably making several dumb mistakes here and there in my game code.
It's ambarassing but even tho I searched everywhere for shader informations, I never realised that they are written in HLSL, so I couldn't find any API
Thank you for the fast reply.