How does JPCT-AE Vertex works on Object3D.addTriangle(...)?

[Hellfire]

Hello friends. How does JPCT-AE Vertex works on Object3D.addTriangle(...)?

Code Select Expand


public static Object3D createCube(float scale) {
Object3D o = new Object3D(12);
float size = scale / 2;

// FRONT
o.addTriangle(new SimpleVector(-size, size, size), new SimpleVector(-size, -size, size), new SimpleVector(size, size, size));
o.addTriangle(new SimpleVector(size, size, size), new SimpleVector(size, -size, size), new SimpleVector(-size, -size, size));

// BACK
o.addTriangle(new SimpleVector(-size, size, -size), new SimpleVector(-size, -size, -size), new SimpleVector(size, size, -size));
o.addTriangle(new SimpleVector(size, size, -size), new SimpleVector(size, -size, -size), new SimpleVector(-size, -size, -size));

// LEFT
o.addTriangle(new SimpleVector(-size, size, size), new SimpleVector(-size, -size, size), new SimpleVector(-size, size, -size));
o.addTriangle(new SimpleVector(-size, size, -size), new SimpleVector(-size, -size, -size), new SimpleVector(-size, -size, size));

// RIGHT
o.addTriangle(new SimpleVector(size, size, size), new SimpleVector(size, -size, size), new SimpleVector(size, size, -size));
o.addTriangle(new SimpleVector(size, size, -size), new SimpleVector(size, -size, -size), new SimpleVector(size, -size, size));

// UPPER
o.addTriangle(new SimpleVector(size, size, size), new SimpleVector(-size, size, size), new SimpleVector(size, size, -size));
o.addTriangle(new SimpleVector(size, size, -size), new SimpleVector(-size, size, -size), new SimpleVector(-size, size, size));

// LOWER
o.addTriangle(new SimpleVector(size, -size, size), new SimpleVector(-size, -size, size), new SimpleVector(size, -size, -size));
o.addTriangle(new SimpleVector(size, -size, -size), new SimpleVector(-size, -size, -size), new SimpleVector(-size, -size, size));
return o;
}

Result:

[EgonOlsen]

Order matters here. jPCT culls away back faces (unless you disable this with setCullling(), but the lighting will be wrong in this case). What is a back face and what isn't is defined by the order of the vertices in a triangle. In this case, reverse the order of the vertices for the faces that aren't visible and they should show up.