Linetest Triangle

Much like testing a line and an axis aligned or OBB intersection, testing a line and triangle intersection utilizes the existing Raycast function. We are going to cast a ray against the triangle being tested. If the Raycast succeeds, we need to make sure that the t value is along the line segment being tested.

Getting ready

We are about to implement a new Linetest function, which will test if a line and a triangle intersect. This function returns a Boolean result.

How to do it…

Follow these steps to check if a line intersects a triangle:

1. Declare the new Linetest function in Geometry3D.h:

   bool Linetest(const Triangle& triangle, const Line& line);

2. Implement the Linetest function in Geometry3D.cpp:

   bool Linetest(const Triangle& triangle, const Line& line) {

3. Construct a ray out of the line being tested:

       Ray ray;
       ray.origin = line.start;
       ray.direction = Normalized(line.end - line.start);

4. Perform a Raycast:

       float t = Raycast(triangle, ray);

5. Check that...