/**
* Intersect the given Ray with this shape. Tests for every triangle of the shape. Speed depends
* hence on the complexity of the shape.
*
* @param Ray ray The Ray to be intersected
* @param Matrix4f transformation The transformation of the Shape into its actual position
* @return a RayShapeIntersection with the coordinates of the HitPoint if any.
*/
public RayShapeIntersection intersect(Ray ray, Matrix4f transformation) {
RayShapeIntersection intersection = new RayShapeIntersection();
List<RayShapeIntersection> hitTriangles = new ArrayList<RayShapeIntersection>();
// get all triangles
Iterator<Triangle> it = getTriangles().iterator();
Triangle triangle;
// calculate intersection of ray and triangle
while (it.hasNext()) {
triangle = it.next();
triangle.transform(transformation);
intersection = calculateIntersection(ray, triangle);
if (intersection.hit) {
hitTriangles.add(intersection);
}
}
Vector3f distance = new Vector3f();
float shortestDist = Float.MAX_VALUE;
for (RayShapeIntersection in : hitTriangles) {
distance.sub(ray.getOrigin(), in.hitPoint);
if (distance.length() < shortestDist) {
intersection = in;
shortestDist = distance.length();
}
}
// return the intersected point if any
return intersection;
}
private List<Triangle> getTriangles() {
List<Triangle> triangles = new ArrayList<Triangle>();
IntBuffer verticesBuffer = mVertexBuffers.getVertexBuffer();
int[] verticesInt = new int[verticesBuffer.capacity()];
for (int i = 0; i < verticesBuffer.capacity(); i++) {
verticesInt[i] = verticesBuffer.get(i);
}
// Fixed Point Conversion
float[] vertices = new float[verticesInt.length];
for (int i = 0; i < verticesInt.length; i++) {
vertices[i] = (float) verticesInt[i] / 65536;
}
ShortBuffer indicesBuffer = mVertexBuffers.getIndexBuffer();
short[] indices = new short[indicesBuffer.capacity()];
for (int i = 0; i < indicesBuffer.capacity(); i++) {
indices[i] = indicesBuffer.get(i);
}
Triangle triangle;
Point3f vec;
for (int i = 0; i < indices.length; i++) {
triangle = new Triangle();
vec = new Point3f();
vec.x = vertices[indices[i] * 3];
vec.y = vertices[indices[i] * 3 + 1];
vec.z = vertices[indices[i] * 3 + 2];
triangle.mX = vec;
i++;
vec = new Point3f();
vec.x = vertices[indices[i] * 3];
vec.y = vertices[indices[i] * 3 + 1];
vec.z = vertices[indices[i] * 3 + 2];
triangle.mY = vec;
i++;
vec = new Point3f();
vec.x = vertices[indices[i] * 3];
vec.y = vertices[indices[i] * 3 + 1];
vec.z = vertices[indices[i] * 3 + 2];
triangle.mZ = vec;
triangles.add(triangle);
}
return triangles;
}