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Utilisation du ArrayMesh¶
Ce tutoriel présente les bases de l'utilisation d'un ArrayMesh.
To do so, we will use the function add_surface_from_arrays(), which takes up to five parameters. The first two are required, while the last three are optional.
The first parameter is the PrimitiveType
, an OpenGL concept that instructs the GPU
how to arrange the primitive based on the vertices given, i.e. whether they represent triangles,
lines, points, etc. See Mesh.PrimitiveType for the options available.
The second parameter, arrays
, is the actual Array that stores the mesh information. The array is a normal Godot array that
is constructed with empty brackets []
. It stores a Packed**Array
(e.g. PackedVector3Array,
PackedInt32Array, etc.) for each type of information that will be used to build the surface.
Common elements of arrays
are listed below, together with the position they must have within arrays
.
See Mesh.ArrayType for a full list.
Index |
Mesh.ArrayType Enum |
Array type |
---|---|---|
0 |
|
|
1 |
|
|
2 |
|
PackedFloat32Array or PackedFloat64Array of groups of 4 floats. The first 3 floats determine the tangent, and the last float the binormal direction as -1 or 1. |
3 |
|
|
4 |
|
|
5 |
|
|
10 |
|
PackedFloat32Array of groups of 4 floats or PackedInt32Array of groups of 4 ints. Each group lists indexes of 4 bones that affects a given vertex. |
11 |
|
PackedFloat32Array or PackedFloat64Array of groups of 4 floats. Each float lists the amount of weight the corresponding bone in |
12 |
|
In most cases when creating a mesh, we define it by its vertex positions. So usually, the array of vertices (at index 0) is required, while the index array (at index 12) is optional and will only be used if included. It is also possible to create a mesh with only the index array and no vertex array, but that's beyond the scope of this tutorial. In fact, we won't use the index array at all.
All the other arrays carry information about the vertices. They are optional and will only be used if included. Some of these arrays (e.g. ARRAY_COLOR
)
use one entry per vertex to provide extra information about vertices. They must have the same size as the vertex array. Other arrays (e.g. ARRAY_TANGENT
) use
four entries to describe a single vertex. These must be exactly four times larger than the vertex array.
For normal usage, the last three parameters in add_surface_from_arrays() are typically left empty.
Setting up the ArrayMesh¶
In the editor, create a MeshInstance3D and add an ArrayMesh to it in the Inspector. Normally, adding an ArrayMesh in the editor is not useful, but in this case it allows us to access the ArrayMesh from code without creating one.
Next, add a script to the MeshInstance3D.
Sous _ready()
, créez un nouvel Array.
var surface_array = []
var surfaceArray = new Godot.Collections.Array();
This will be the array that we keep our surface information in - it will hold
all the arrays of data that the surface needs. Godot will expect it to be of
size Mesh.ARRAY_MAX
, so resize it accordingly.
var surface_array = []
surface_array.resize(Mesh.ARRAY_MAX)
var surfaceArray = new Godot.Collections.Array();
surfaceArray.Resize((int)Mesh.ArrayType.Max);
Créez ensuite les arrays pour chaque type de données que vous utiliserez.
var verts = PackedVector3Array()
var uvs = PackedVector2Array()
var normals = PackedVector3Array()
var indices = PackedInt32Array()
var verts = new List<Vector3>();
var uvs = new List<Vector2>();
var normals = new List<Vector3>();
var indices = new List<int>();
Une fois que vous avez rempli vos arrays de données avec votre géométrie, vous pouvez créer un maillage en ajoutant chaque array à surface_array
, puis en validant le maillage.
surface_array[Mesh.ARRAY_VERTEX] = verts
surface_array[Mesh.ARRAY_TEX_UV] = uvs
surface_array[Mesh.ARRAY_NORMAL] = normals
surface_array[Mesh.ARRAY_INDEX] = indices
# No blendshapes, lods, or compression used.
mesh.add_surface_from_arrays(Mesh.PRIMITIVE_TRIANGLES, surface_array)
surfaceArray[(int)Mesh.ArrayType.Vertex] = verts.ToArray();
surfaceArray[(int)Mesh.ArrayType.TexUV] = uvs.ToArray();
surfaceArray[(int)Mesh.ArrayType.Normal] = normals.ToArray();
surfaceArray[(int)Mesh.ArrayType.Index] = indices.ToArray();
var arrMesh = Mesh as ArrayMesh;
if (arrMesh != null)
{
// No blendshapes, lods, or compression used.
arrMesh.AddSurfaceFromArrays(Mesh.PrimitiveType.Triangles, surfaceArray);
}
Note
Dans cet exemple, nous avons utilisé Mesh.PRIMITIVE_TRIANGLES
, mais vous pouvez utiliser n'importe quel type primitif disponible à partir de mesh.
Mis ensemble, le code complet ressemble à ceci :
extends MeshInstance3D
func _ready():
var surface_array = []
surface_array.resize(Mesh.ARRAY_MAX)
# PackedVector**Arrays for mesh construction.
var verts = PackedVector3Array()
var uvs = PackedVector2Array()
var normals = PackedVector3Array()
var indices = PackedInt32Array()
#######################################
## Insert code here to generate mesh ##
#######################################
# Assign arrays to surface array.
surface_array[Mesh.ARRAY_VERTEX] = verts
surface_array[Mesh.ARRAY_TEX_UV] = uvs
surface_array[Mesh.ARRAY_NORMAL] = normals
surface_array[Mesh.ARRAY_INDEX] = indices
# Create mesh surface from mesh array.
# No blendshapes, lods, or compression used.
mesh.add_surface_from_arrays(Mesh.PRIMITIVE_TRIANGLES, surface_array)
public partial class MyMeshInstance3D : MeshInstance3D
{
public override void _Ready()
{
var surfaceArray = new Godot.Collections.Array();
surfaceArray.Resize((int)Mesh.ArrayType.Max);
// C# arrays cannot be resized or expanded, so use Lists to create geometry.
var verts = new List<Vector3>();
var uvs = new List<Vector2>();
var normals = new List<Vector3>();
var indices = new List<int>();
/***********************************
* Insert code here to generate mesh.
* *********************************/
// Convert Lists to arrays and assign to surface array
surfaceArray[(int)Mesh.ArrayType.Vertex] = verts.ToArray();
surfaceArray[(int)Mesh.ArrayType.TexUV] = uvs.ToArray();
surfaceArray[(int)Mesh.ArrayType.Normal] = normals.ToArray();
surfaceArray[(int)Mesh.ArrayType.Index] = indices.ToArray();
var arrMesh = Mesh as ArrayMesh;
if (arrMesh != null)
{
// Create mesh surface from mesh array
// No blendshapes, lods, or compression used.
arrMesh.AddSurfaceFromArrays(Mesh.PrimitiveType.Triangles, surfaceArray);
}
}
}
The code that goes in the middle can be whatever you want. Below we will present some example code for generating a sphere.
Génération de la géométrie¶
Voici un exemple de code pour générer une sphère. Bien que le code soit présenté en GDScript, il n'y a rien de spécifique à Godot dans l'approche de sa génération. Cette implémentation n'a rien de particulier à voir avec ArrayMeshes et n'est qu'une approche générique pour générer une sphère. Si vous avez du mal à comprendre ou si vous souhaitez en savoir plus sur la géométrie procédurale en général, vous pouvez utiliser n'importe quel tutoriel que vous trouverez en ligne.
extends MeshInstance3D
var rings = 50
var radial_segments = 50
var radius = 1
func _ready():
# Insert setting up the PackedVector**Arrays here.
# Vertex indices.
var thisrow = 0
var prevrow = 0
var point = 0
# Loop over rings.
for i in range(rings + 1):
var v = float(i) / rings
var w = sin(PI * v)
var y = cos(PI * v)
# Loop over segments in ring.
for j in range(radial_segments):
var u = float(j) / radial_segments
var x = sin(u * PI * 2.0)
var z = cos(u * PI * 2.0)
var vert = Vector3(x * radius * w, y * radius, z * radius * w)
verts.append(vert)
normals.append(vert.normalized())
uvs.append(Vector2(u, v))
point += 1
# Create triangles in ring using indices.
if i > 0 and j > 0:
indices.append(prevrow + j - 1)
indices.append(prevrow + j)
indices.append(thisrow + j - 1)
indices.append(prevrow + j)
indices.append(thisrow + j)
indices.append(thisrow + j - 1)
if i > 0:
indices.append(prevrow + radial_segments - 1)
indices.append(prevrow)
indices.append(thisrow + radial_segments - 1)
indices.append(prevrow)
indices.append(prevrow + radial_segments)
indices.append(thisrow + radial_segments - 1)
prevrow = thisrow
thisrow = point
# Insert committing to the ArrayMesh here.
public partial class MyMeshInstance3D : MeshInstance3D
{
private int _rings = 50;
private int _radialSegments = 50;
private float _radius = 1;
public override void _Ready()
{
// Insert setting up the surface array and lists here.
// Vertex indices.
var thisRow = 0;
var prevRow = 0;
var point = 0;
// Loop over rings.
for (var i = 0; i < _rings + 1; i++)
{
var v = ((float)i) / _rings;
var w = Mathf.Sin(Mathf.Pi * v);
var y = Mathf.Cos(Mathf.Pi * v);
// Loop over segments in ring.
for (var j = 0; j < _radialSegments; j++)
{
var u = ((float)j) / _radialSegments;
var x = Mathf.Sin(u * Mathf.Pi * 2);
var z = Mathf.Cos(u * Mathf.Pi * 2);
var vert = new Vector3(x * _radius * w, y * _radius, z * _radius * w);
verts.Add(vert);
normals.Add(vert.Normalized());
uvs.Add(new Vector2(u, v));
point += 1;
// Create triangles in ring using indices.
if (i > 0 && j > 0)
{
indices.Add(prevRow + j - 1);
indices.Add(prevRow + j);
indices.Add(thisRow + j - 1);
indices.Add(prevRow + j);
indices.Add(thisRow + j);
indices.Add(thisRow + j - 1);
}
}
if (i > 0)
{
indices.Add(prevRow + _radialSegments - 1);
indices.Add(prevRow);
indices.Add(thisRow + _radialSegments - 1);
indices.Add(prevRow);
indices.Add(prevRow + _radialSegments);
indices.Add(thisRow + _radialSegments - 1);
}
prevRow = thisRow;
thisRow = point;
}
// Insert committing to the ArrayMesh here.
}
}
Enregistrer¶
Finally, we can use the ResourceSaver class to save the ArrayMesh. This is useful when you want to generate a mesh and then use it later without having to re-generate it.
# Saves mesh to a .tres file with compression enabled.
ResourceSaver.save(mesh, "res://sphere.tres", ResourceSaver.FLAG_COMPRESS)
// Saves mesh to a .tres file with compression enabled.
ResourceSaver.Save(Mesh, "res://sphere.tres", ResourceSaver.SaverFlags.Compress);