koobas.hobune.stream
Display a simple mesh (2D square) on the screen?
Hi,
For a test I'm trying to just display a simple mesh (2D square) on the screen.
I created an empty gameobject with just a MeshFilter component and a Script component. Here's the simple code in UnityScript. There's no errors, but it doesn't show anything on the screen.
function Start () {
// Create the vertices
var Vertices = Array();
Vertices[0] = Vector3(0, 0, 0);
Vertices[1] = Vector3(1, 0, 0);
Vertices[2] = Vector3(0, 1, 0);
Vertices[3] = Vector3(1, 1, 1);
// Create the UVs
var UVs = Array();
UVs[0] = Vector2(0, 1);
UVs[1] = Vector2(1, 1);
UVs[2] = Vector2(0, 0);
UVs[3] = Vector2(1, 0);
// Create the 2 triangles
var triangles = [ 0, 1, 3, 3, 2, 0 ];
// Display the mesh
var m = Mesh();
GetComponent.<MeshFilter>().mesh = m;
m.vertices = Vertices;
m.uv = UVs;
m.triangles = triangles;
}
Can you see where's my mistake? Thanks!
I use C# not JS so you're going to have to search some of this on your own but I can see a few mistakes. First you actually need to create a new gameobject to create the mesh on.
var square: GameObject;
square= new GameObject ("Square");
You then need to use AddComponent to create a MeshRenderer and a MeshFilter or nothing is going to render.
I'm not sure why var m = Mesh(); isn't resulting in an error, perhaps in JS it doesn't but if you check the documentation you'll see what you should be using.
Also your vertices do not describe a square. A two dimensional shape is always going to have one axis that is all the same but you are modifying all three, hence creating a three dimensional shape. Your vertices describe a square folded over on itself with dodgy normals.
Vertices[0] = Vector3(-1, 0, -1);
Vertices[1] = Vector3(-1, 0, 1);
Vertices[2] = Vector3(1, 0, 1);
Vertices[3] = Vector3(1, 0, -1);
That is for a square. Whichever axis you want it to be drawn on should all be the same, ie 0.
Your triangles are also wrong.
var triangles = [ 0, 1, 2, 0, 2, 3 ];
Those are the values you want to go with the above vertices.
Which makes the UV co-ordinates:
UVs[0] = Vector2(0, 0);
UVs[1] = Vector2(0, 1);
UVs[2] = Vector2(1, 1);
UVs[3] = Vector2(1, 0);
It may then be necessary to use RecalculateNormals for it to display correctly.
You may also want to declare the values of m.vertices and m.uv directly rather than in a separate array.
