ProceduralPrimitives

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m (C# - Cone: "Note that cylinders (bottomRadius == topRadius) and pyramids (4 sides, topRadius == 0) are types of cones, and can be created with this script.")
(Torus added, and a tip section.)
Line 345: Line 345:
 
mesh.Optimize();
 
mesh.Optimize();
 
</syntaxhighlight>
 
</syntaxhighlight>
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 +
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== C# - Torus ==
 +
 +
<syntaxhighlight lang="csharp">
 +
MeshFilter filter = gameObject.AddComponent< MeshFilter >();
 +
Mesh mesh = filter.mesh;
 +
mesh.Clear();
 +
 +
float radius1 = 5f;
 +
float radius2 = 2f;
 +
int nbRadSeg = 24;
 +
int nbSides = 18;
 +
 +
#region Vertices
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Vector3[] vertices = new Vector3[(nbRadSeg+1) * (nbSides+1)];
 +
float _2pi = Mathf.PI * 2f;
 +
for( int seg = 0; seg <= nbRadSeg; seg++ )
 +
{
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int currSeg = seg  == nbRadSeg ? 0 : seg;
 +
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float t1 = (float)currSeg / nbRadSeg * _2pi;
 +
Vector3 r1 = new Vector3( Mathf.Cos(t1) * radius1, 0f, Mathf.Sin(t1) * radius1 );
 +
 +
for( int side = 0; side <= nbSides; side++ )
 +
{
 +
int currSide = side == nbSides ? 0 : side;
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Vector3 normale = Vector3.Cross( r1, Vector3.up );
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float t2 = (float)currSide / nbSides * _2pi;
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Vector3 r2 = Quaternion.AngleAxis( -t1 * Mathf.Rad2Deg, Vector3.up ) *new Vector3( Mathf.Sin(t2) * radius2, Mathf.Cos(t2) * radius2 );
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vertices[side + seg * (nbSides+1)] = r1 + r2;
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}
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}
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#endregion
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#region UVs
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Vector2[] uvs = new Vector2[vertices.Length];
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for( int seg = 0; seg <= nbRadSeg; seg++ )
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for( int side = 0; side <= nbSides; side++ )
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uvs[side + seg * (nbSides+1)] = new Vector2( (float)seg / nbRadSeg, (float)side / nbSides );
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#endregion
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#region Triangles
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int nbFaces = vertices.Length;
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int nbTriangles = nbFaces * 2;
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int nbIndexes = nbTriangles * 3;
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int[] triangles = new int[ nbIndexes ];
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 +
int i = 0;
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for( int seg = 0; seg <= nbRadSeg; seg++ )
 +
{
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for( int side = 0; side <= nbSides - 1; side++ )
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{
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int current = side + seg * (nbSides+1);
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int next = side + (seg < (nbRadSeg) ?(seg+1) * (nbSides+1) : 0);
 +
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if( i < triangles.Length - 6 )
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{
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triangles[i++] = current;
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triangles[i++] = next;
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triangles[i++] = next+1;
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triangles[i++] = current;
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triangles[i++] = next+1;
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triangles[i++] = current+1;
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}
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}
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}
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#endregion
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mesh.vertices = vertices;
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mesh.uv = uvs;
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mesh.triangles = triangles;
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mesh.RecalculateNormals();
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mesh.RecalculateBounds();
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mesh.Optimize();
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</syntaxhighlight>
 +
 +
 +
== Tips ==
 +
 +
Dealing with all thoses vertices and indexes can give you a headache before you know it. To see things clearly, you can create a TextMesh, set it up properly (small characters, anchor at middle-center) and save it as a prefab. Then, instantiate one at each vertices to see those indexes, like so :
 +
 +
 +
<syntaxhighlight lang="csharp">int i = 0;
 +
foreach( Vector3 pos in vertices )
 +
{
 +
TextMesh tm = GameObject.Instantiate( tmPrefab, pos, Quaternion.identity ) as TextMesh;
 +
tm.name = (i).ToString();
 +
tm.text = (i++).ToString();
 +
tm.transform.parent = transform;
 +
}
 +
</syntaxhighlight>
 +
 +
PS : A lookat script might be usefull on those guys, with the editor's cam as target (Camera.current).

Revision as of 00:28, 26 January 2013

Author: Bérenger.

Contents

Description

Use those scripts to procedurally create primitive meshes, with custom parameters. More to come later. If anyone has the code for a teapot, that'd be great. I guess it's a tiny bit more complicated though.

Usage

The entry point of those script must be a reference to a meshfilter's mesh. The return value is that mesh filled up.


C# - Plane

// You can change that line to provide another MeshFilter
MeshFilter filter = gameObject.AddComponent< MeshFilter >();
Mesh mesh = filter.mesh;
mesh.Clear();
 
float length = 1f;
float width = 1f;
int resX = 2; // 2 minimum
int resZ = 2;
 
#region Vertices		
Vector3[] vertices = new Vector3[ resX * resZ ];
for(int z = 0; z < resZ; z++)
{
	// [ -length / 2, length / 2 ]
	float zPos = ((float)z / (resZ - 1) - .5f) * length;
	for(int x = 0; x < resX; x++)
	{
		// [ -width / 2, width / 2 ]
		float xPos = ((float)x / (resX - 1) - .5f) * width;
		vertices[ x + z * resX ] = new Vector3( xPos, 0f, zPos );
	}
}
#endregion
 
#region UVs		
Vector2[] uvs = new Vector2[ vertices.Length ];
for(int v = 0; v < resZ; v++)
{
	for(int u = 0; u < resX; u++)
	{
		uvs[ u + v * resX ] = new Vector2( (float)u / (resX - 1), (float)v / (resZ - 1) );
	}
}
#endregion
 
#region Triangles
int nbFaces = (resX - 1) * (resZ - 1);
int[] triangles = new int[ nbFaces * 6 ];
int t = 0;
for(int face = 0; face < nbFaces; face++ )
{
	// Retrieve lower left corner from face ind
	int i = face % (resX - 1) + (face / (resZ - 1) * resX);
 
	triangles[t++] = i + resX;
	triangles[t++] = i + 1;
	triangles[t++] = i;
 
	triangles[t++] = i + resX;	
	triangles[t++] = i + resX + 1;
	triangles[t++] = i + 1; 
}
#endregion
 
mesh.vertices = vertices;
mesh.uv = uvs;
mesh.triangles = triangles;
 
mesh.RecalculateNormals();
mesh.RecalculateBounds();
mesh.Optimize();


C# - Box

// You can change that line to provide another MeshFilter
MeshFilter filter = gameObject.AddComponent< MeshFilter >();
Mesh mesh = filter.mesh;
mesh.Clear();
 
float length = 1f;
float width = 1f;
float height = 1f;
 
#region Vertices
Vector3 p0 = new Vector3( -length * .5f,	-width * .5f, height * .5f );
Vector3 p1 = new Vector3( length * .5f, 	-width * .5f, height * .5f );
Vector3 p2 = new Vector3( length * .5f, 	-width * .5f, -height * .5f );
Vector3 p3 = new Vector3( -length * .5f,	-width * .5f, -height * .5f );	
 
Vector3 p4 = new Vector3( -length * .5f,	width * .5f,  height * .5f );
Vector3 p5 = new Vector3( length * .5f, 	width * .5f,  height * .5f );
Vector3 p6 = new Vector3( length * .5f, 	width * .5f,  -height * .5f );
Vector3 p7 = new Vector3( -length * .5f,	width * .5f,  -height * .5f );
 
Vector3[] vertices = new Vector3[]
{
	// Bottom
	p0, p1, p2, p3,
 
	// Left
	p7, p4, p0, p3,
 
	// Front
	p4, p5, p1, p0,
 
	// Back
	p6, p7, p3, p2,
 
	// Right
	p5, p6, p2, p1,
 
	// Top
	p7, p6, p5, p4
};
#endregion
 
#region UVs
Vector2 _00 = new Vector2( 0f, 0f );
Vector2 _10 = new Vector2( 1f, 0f );
Vector2 _01 = new Vector2( 0f, 1f );
Vector2 _11 = new Vector2( 1f, 1f );
 
Vector2[] uvs = new Vector2[]
{
	// Bottom
	_11, _01, _00, _10,
 
	// Left
	_11, _01, _00, _10,
 
	// Front
	_11, _01, _00, _10,
 
	// Back
	_11, _01, _00, _10,
 
	// Right
	_11, _01, _00, _10,
 
	// Top
	_11, _01, _00, _10,
};
#endregion
 
#region Triangles
int[] triangles = new int[]
{
	// Bottom
	3, 1, 0,
	3, 2, 1,			
 
	// Left
	3 + 4 * 1, 1 + 4 * 1, 0 + 4 * 1,
	3 + 4 * 1, 2 + 4 * 1, 1 + 4 * 1,
 
	// Front
	3 + 4 * 2, 1 + 4 * 2, 0 + 4 * 2,
	3 + 4 * 2, 2 + 4 * 2, 1 + 4 * 2,
 
	// Back
	3 + 4 * 3, 1 + 4 * 3, 0 + 4 * 3,
	3 + 4 * 3, 2 + 4 * 3, 1 + 4 * 3,
 
	// Right
	3 + 4 * 4, 1 + 4 * 4, 0 + 4 * 4,
	3 + 4 * 4, 2 + 4 * 4, 1 + 4 * 4,
 
	// Top
	3 + 4 * 5, 1 + 4 * 5, 0 + 4 * 5,
	3 + 4 * 5, 2 + 4 * 5, 1 + 4 * 5,
 
};
#endregion
 
mesh.vertices = vertices;
mesh.uv = uvs;
mesh.triangles = triangles;
 
mesh.RecalculateNormals();
mesh.RecalculateBounds();
mesh.Optimize();


C# - Cone

Note that cylinders (bottomRadius == topRadius) and pyramids (4 sides, topRadius == 0) are types of cones, and can be created with this script.

MeshFilter filter = gameObject.AddComponent<MeshFilter>();
Mesh mesh = filter.mesh;
mesh.Clear();
 
float height = 1f;
float bottomRadius = .25f;
float topRadius = .05f;
int nbSides = 18;
int nbHeightSeg = 1; // Not implemented yet
 
int nbVerticesCap = nbSides + 1;
#region Vertices
 
// bottom + top + sides
Vector3[] vertices = new Vector3[nbVerticesCap + nbVerticesCap + nbSides * nbHeightSeg * 2 + 2];
int vert = 0;
float _2pi = Mathf.PI * 2f;
 
// Bottom cap
vertices[vert++] = new Vector3(0f, 0f, 0f);
while( vert <= nbSides )
{
	float rad = (float)vert / nbSides * _2pi;
	vertices[vert] = new Vector3(Mathf.Cos(rad) * bottomRadius, 0f, Mathf.Sin(rad) * bottomRadius);
	vert++;
}
 
// Top cap
vertices[vert++] = new Vector3(0f, height, 0f);
while (vert <= nbSides * 2 + 1)
{
	float rad = (float)(vert - nbSides - 1)  / nbSides * _2pi;
	vertices[vert] = new Vector3(Mathf.Cos(rad) * topRadius, height, Mathf.Sin(rad) * topRadius);
	vert++;
}
 
// Sides
int v = 0;
while (vert <= vertices.Length - 4 )
{
	float rad = (float)v / nbSides * _2pi;
	vertices[vert] = new Vector3(Mathf.Cos(rad) * topRadius, height, Mathf.Sin(rad) * topRadius);
	vertices[vert + 1] = new Vector3(Mathf.Cos(rad) * bottomRadius, 0, Mathf.Sin(rad) * bottomRadius);
	vert+=2;
	v++;
}
vertices[vert] = vertices[ nbSides * 2 + 2 ];
vertices[vert + 1] = vertices[nbSides * 2 + 3 ];
#endregion
 
#region UVs
Vector2[] uvs = new Vector2[vertices.Length];
 
// Bottom cap
int u = 0;
uvs[u++] = new Vector2(0.5f, 0.5f);
while (u <= nbSides)
{
    float rad = (float)u / nbSides * _2pi;
    uvs[u] = new Vector2(Mathf.Cos(rad) * .5f + .5f, Mathf.Sin(rad) * .5f + .5f);
    u++;
}
 
// Top cap
uvs[u++] = new Vector2(0.5f, 0.5f);
while (u <= nbSides * 2 + 1)
{
    float rad = (float)u / nbSides * _2pi;
    uvs[u] = new Vector2(Mathf.Cos(rad) * .5f + .5f, Mathf.Sin(rad) * .5f + .5f);
    u++;
}
 
// Sides
int u_sides = 0;
while (u <= uvs.Length - 4 )
{
    float t = (float)u_sides / nbSides;
    uvs[u] = new Vector3(t, 1f);
    uvs[u + 1] = new Vector3(t, 0f);
    u += 2;
    u_sides++;
}
uvs[u] = new Vector2(1f, 1f);
uvs[u + 1] = new Vector2(1f, 0f);
#endregion
 
#region Triangles
int nbTriangles = nbSides + nbSides + nbSides*2;
int[] triangles = new int[nbTriangles * 3 + 3];
 
// Bottom cap
int tri = 0;
int i = 0;
while (tri < nbSides - 1)
{
	triangles[ i ] = 0;
	triangles[ i+1 ] = tri + 1;
	triangles[ i+2 ] = tri + 2;
	tri++;
	i += 3;
}
triangles[i] = 0;
triangles[i + 1] = tri + 1;
triangles[i + 2] = 1;
tri++;
i += 3;
 
// Top cap
//tri++;
while (tri < nbSides*2)
{
	triangles[ i ] = tri + 2;
	triangles[i + 1] = tri + 1;
	triangles[i + 2] = nbVerticesCap;
	tri++;
	i += 3;
}
 
triangles[i] = nbVerticesCap + 1;
triangles[i + 1] = tri + 1;
triangles[i + 2] = nbVerticesCap;		
tri++;
i += 3;
tri++;
 
// Sides
while( tri <= nbTriangles )
{
	triangles[ i ] = tri + 2;
	triangles[ i+1 ] = tri + 1;
	triangles[ i+2 ] = tri + 0;
	tri++;
	i += 3;
 
	triangles[ i ] = tri + 1;
	triangles[ i+1 ] = tri + 2;
	triangles[ i+2 ] = tri + 0;
	tri++;
	i += 3;
}
#endregion
 
mesh.vertices = vertices;
mesh.uv = uvs;
mesh.triangles = triangles;
 
mesh.RecalculateNormals();
mesh.RecalculateBounds();
mesh.Optimize();


C# - Torus

MeshFilter filter = gameObject.AddComponent< MeshFilter >();
Mesh mesh = filter.mesh;
mesh.Clear();
 
float radius1 = 5f;
float radius2 = 2f;
int nbRadSeg = 24;
int nbSides = 18;
 
#region Vertices		
Vector3[] vertices = new Vector3[(nbRadSeg+1) * (nbSides+1)];
float _2pi = Mathf.PI * 2f;
for( int seg = 0; seg <= nbRadSeg; seg++ )
{
	int currSeg = seg  == nbRadSeg ? 0 : seg;
 
	float t1 = (float)currSeg / nbRadSeg * _2pi;
	Vector3 r1 = new Vector3( Mathf.Cos(t1) * radius1, 0f, Mathf.Sin(t1) * radius1 );
 
	for( int side = 0; side <= nbSides; side++ )
	{
		int currSide = side == nbSides ? 0 : side;
 
		Vector3 normale = Vector3.Cross( r1, Vector3.up );
		float t2 = (float)currSide / nbSides * _2pi;
		Vector3 r2 = Quaternion.AngleAxis( -t1 * Mathf.Rad2Deg, Vector3.up ) *new Vector3( Mathf.Sin(t2) * radius2, Mathf.Cos(t2) * radius2 );
 
		vertices[side + seg * (nbSides+1)] = r1 + r2;
	}
}
#endregion
 
#region UVs
Vector2[] uvs = new Vector2[vertices.Length];
for( int seg = 0; seg <= nbRadSeg; seg++ )
	for( int side = 0; side <= nbSides; side++ )
		uvs[side + seg * (nbSides+1)] = new Vector2( (float)seg / nbRadSeg, (float)side / nbSides );
#endregion
 
#region Triangles
int nbFaces = vertices.Length;
int nbTriangles = nbFaces * 2;
int nbIndexes = nbTriangles * 3;
int[] triangles = new int[ nbIndexes ];
 
int i = 0;
for( int seg = 0; seg <= nbRadSeg; seg++ )
{			
	for( int side = 0; side <= nbSides - 1; side++ )
	{
		int current = side + seg * (nbSides+1);
		int next = side + (seg < (nbRadSeg) ?(seg+1) * (nbSides+1) : 0);
 
		if( i < triangles.Length - 6 )
		{
			triangles[i++] = current;
			triangles[i++] = next;
			triangles[i++] = next+1;
 
			triangles[i++] = current;
			triangles[i++] = next+1;
			triangles[i++] = current+1;
		}
	}
}
#endregion
 
mesh.vertices = vertices;
mesh.uv = uvs;
mesh.triangles = triangles;
 
mesh.RecalculateNormals();
mesh.RecalculateBounds();
mesh.Optimize();


Tips

Dealing with all thoses vertices and indexes can give you a headache before you know it. To see things clearly, you can create a TextMesh, set it up properly (small characters, anchor at middle-center) and save it as a prefab. Then, instantiate one at each vertices to see those indexes, like so :


int i = 0;
foreach( Vector3 pos in vertices )
{
	TextMesh tm = GameObject.Instantiate( tmPrefab, pos, Quaternion.identity ) as TextMesh;
	tm.name = (i).ToString();
	tm.text = (i++).ToString();
	tm.transform.parent = transform;
}

PS : A lookat script might be usefull on those guys, with the editor's cam as target (Camera.current).

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