Triangle

If you don't remember how an obj is loaded / constructred, now would be a good time to review that before moving on. It's going to be important later in the chapter.

All 3D models are just a collection of triangles! As such, let's create a triangle primitive. A triangle is just a collection of 3 points. Be sure to add this class to your primitives folder, as a triangle is a primitive.

I'll implemented the entire triangle class below, it's so simple there is nothing else to do.

using System;
using OpenTK.Graphics.OpenGL;
using Math_Implementation;

namespace CollisionDetectionSelector.Primitives {
    class Triangle {
        public Point p0 = new Point();
        public Point p1 = new Point();
        public Point p2 = new Point();

        public Triangle() {

        }

        public Triangle(Point _p0, Point _p1, Point _p2) {
            p0 = new Point(_p0.ToVector());
            p1 = new Point(_p1.ToVector());
            p2 = new Point(_p2.ToVector());
        }

        public Triangle(Vector3 _p0, Vector3 _p1, Vector3 _p2) {
            p0 = new Point(_p0);
            p1 = new Point(_p1);
            p2 = new Point(_p2);
        }

        public void Render() {
            GL.Begin(PrimitiveType.Triangles);

            GL.Vertex3(p0.X, p0.Y, p0.Z);
            GL.Vertex3(p1.X, p1.Y, p1.Z);
            GL.Vertex3(p2.X, p2.Y, p2.Z);

            GL.End();
        }

        public override string ToString() {
            return "p0: " + p0.ToString() + ", p1: " + p1.ToString() + ", p2: " + p2.ToString();
        }
    }
}