private static vec3 GenNormal(vertex a, vertex b, vertex c)
{
var dir1 = a.pos - c.pos;
var dir2 = b.pos - c.pos;
return(dir1.cross(dir2));
//return OpenTK.Vector3.Cross(dir1.ToOpenTKVec(), dir2.ToOpenTKVec()).ToNumsVec();
}
public vertex VertexFurthestAwayFromPivot()
{
vertex res = this.vertices[0];
for (int i = 1; i < this.vertices.Count; i++)
{
if (res.pos.sqlength < this.vertices[i].pos.sqlength)
{
res = vertices[i];
}
}
return(res);
}
public Triangle(vertex v1, vertex v2, vertex v3, uint i1, uint i2, uint i3)
{
this.v1 = v1; this.v2 = v2; this.v3 = v3;
this.i1 = i1; this.i2 = i2; this.i3 = i3;
}
public static Mesh GenCube()
{
const float k = 0.5f;
const float n = -k;
var verts = new vertex[] {
// front side
new vertex(new vec3(n, n, n), new vec2(), new vec3()),
new vertex(new vec3(k, n, n), new vec2(), new vec3()),
new vertex(new vec3(n, k, n), new vec2(), new vec3()),
new vertex(new vec3(k, k, n), new vec2(), new vec3()),
// back side
new vertex(new vec3(n, n, k), new vec2(), new vec3()),
new vertex(new vec3(k, n, k), new vec2(), new vec3()),
new vertex(new vec3(n, k, k), new vec2(), new vec3()),
new vertex(new vec3(k, k, k), new vec2(), new vec3()),
// right side
new vertex(new vec3(n, n, n), new vec2(), new vec3()),
new vertex(new vec3(n, k, n), new vec2(), new vec3()),
new vertex(new vec3(n, n, k), new vec2(), new vec3()),
new vertex(new vec3(n, k, k), new vec2(), new vec3()),
// left side
new vertex(new vec3(k, n, n), new vec2(), new vec3()),
new vertex(new vec3(k, n, k), new vec2(), new vec3()),
new vertex(new vec3(k, k, n), new vec2(), new vec3()),
new vertex(new vec3(k, k, k), new vec2(), new vec3()),
// top side
new vertex(new vec3(n, k, n), new vec2(), new vec3()),
new vertex(new vec3(k, k, n), new vec2(), new vec3()),
new vertex(new vec3(k, k, k), new vec2(), new vec3()),
new vertex(new vec3(n, k, k), new vec2(), new vec3()),
// bottom side
new vertex(new vec3(n, n, n), new vec2(), new vec3()),
new vertex(new vec3(k, n, n), new vec2(), new vec3()),
new vertex(new vec3(k, n, k), new vec2(), new vec3()),
new vertex(new vec3(n, n, k), new vec2(), new vec3()),
};
var ind = new uint[] {
/*0,1,2, 2,1,3, // front
* 4,6,5, 7,5,6, // back
* 8,9,10, 11,10,9, // right
* 12,13,14, 15,14,13, // left
* 16,17,18, 19,16,18, // top
* 20,23,22, 21,20,22 // bottom
*/
2, 1, 0, 3, 1, 2, // front
5, 6, 4, 6, 5, 7, // back
10, 9, 8, 9, 10, 11, // right
14, 13, 12, 13, 14, 15, // left
18, 17, 16, 18, 16, 19, // top
22, 23, 20, 22, 20, 21 // bottom
};
var m = new Mesh(verts, ind);
m.GenNormals();
return(m);
}
public vertex lerp(vertex other, float time)
{
return(new vertex(pos.lerp(other.pos, time), texcoord.lerp(other.texcoord, time), normal.lerp(other.normal, time)));
}
private void subdivide()
{
int icount = indices.Count;
var ind = new uint[icount];
indices.CopyTo(ind);
indices.Clear();
var vex = new vertex[vertices.Count];
vertices.CopyTo(vex);
vertices.Clear();
void _vertex(vertex v)
{
var i = vertices.IndexOf(v);
if (i == -1)
{
vertices.Add(v);
i = vertices.Count - 1;
}
indices.Add((uint)i);
}
for (int i = 0; i < icount; i += 3)
{
uint i1 = ind[i],
i2 = ind[i + 1],
i3 = ind[i + 2];
vertex v1 = vex[i1],
v2 = vex[i2],
v3 = vex[i3];
/* v3
* o
* / \
* vm2 o---o vm3
* / \ / \
* o---o---o
* v1 vm1 v2 */
vertex vm1 = v1.lerp(v2, .5f),
vm2 = v1.lerp(v3, .5f),
vm3 = v2.lerp(v3, .5f);
// triangle 1 (lower left)
_vertex(v1); _vertex(vm1); _vertex(vm2);
// triangle 2 (middle)
_vertex(vm1); _vertex(vm3); _vertex(vm2);
// triangle 3 (lower right)
_vertex(vm1); _vertex(v2); _vertex(vm3);
// triangle 4 (top)
_vertex(vm2); _vertex(vm3); _vertex(v3);
}
}