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How do you create a mesh in code using DOTS?

Discussion in 'Data Oriented Technology Stack' started by Manablight, Feb 14, 2020 at 10:02 PM.

  1. Manablight

    Manablight

    Joined:
    Aug 11, 2014
    Posts:
    2
    I'd like to create a mesh in code, lets say a quad. With a GameObject I could do it with the following Monobehavior. the new entities and components can only use primitive types? How would I go about doing this with the new DOTS setup?

    Code (CSharp):
    1. Mesh mesh = new Mesh();
    2.  
    3.     Vector3[] vertices = new Vector3[4];
    4.     Vector3[] normals = new Vector3[4];
    5.     Vector2[] uvs = new Vector2[4];
    6.     int[] triangles = new int[6];
    7.  
    8.     Vector2 uv00 = new Vector2( 0f, 0f );
    9.     Vector2 uv10 = new Vector2( 1f, 0f );
    10.     Vector2 uv01 = new Vector2( 0f, 1f );
    11.     Vector2 uv11 = new Vector2( 1f, 1f );
    12.  
    13.     Vector3 p0 = new Vector3( -0.5f,  -0.5f,  0.5f );
    14.     Vector3 p1 = new Vector3(  0.5f,  -0.5f,  0.5f );
    15.     Vector3 p2 = new Vector3(  0.5f,  -0.5f, -0.5f );
    16.     Vector3 p3 = new Vector3( -0.5f,  -0.5f, -0.5f );      
    17.     Vector3 p4 = new Vector3( -0.5f,   0.5f,  0.5f );
    18.     Vector3 p5 = new Vector3(  0.5f,   0.5f,  0.5f );
    19.     Vector3 p6 = new Vector3(  0.5f,   0.5f, -0.5f );
    20.     Vector3 p7 = new Vector3( -0.5f,   0.5f, -0.5f );
    21.  
    22.  
    23.     vertices = new Vector3[] {p4, p5, p1, p0};
    24.     normals = new Vector3[] {Vector3.forward,
    25.                              Vector3.forward,
    26.                              Vector3.forward,
    27.                              Vector3.forward};
    28.  
    29.     uvs = new Vector2[] {uv11, uv01, uv00, uv10};
    30.     triangles = new int[] {3, 1, 0, 3, 2, 1};
    31.  
    32.     mesh.vertices = vertices;
    33.     mesh.normals = normals;
    34.     mesh.uv = uvs;
    35.     mesh.triangles = triangles;
    36.    
    37.     mesh.RecalculateBounds();
    38.  
    39.     GameObject quad = new GameObject("quad");
    40.     quad.transform.parent = this.gameObject.transform;
    41.      MeshFilter meshFilter = (MeshFilter) quad.AddComponent(typeof(MeshFilter));
    42.     meshFilter.mesh = mesh;
    43.     MeshRenderer renderer = quad.AddComponent(typeof(MeshRenderer)) as MeshRenderer;
    44.     renderer.material = cubeMaterial;
     
  2. Vanamerax

    Vanamerax

    Joined:
    Jan 12, 2012
    Posts:
    850
    If the quad is always the same for many entities, I would store mesh data in a renderer system and add a tag component to the entities for which you want to render the quad. Or you can store the mesh data in a sharedcomponent that can contain reference types. Then loop over these entities to call Graphics.DrawMeshInstanced for each of them.

    This is basically what the hybridrenderer package does.
     
  3. Manablight

    Manablight

    Joined:
    Aug 11, 2014
    Posts:
    2
    Thanks for the reply
     
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