Ray Picking Problems
- by A Name I Haven't Decided On
I've read so many answers on here about how to do Ray Picking, that I thought I had the idea of it down. But when I try to implement it in my game, I get garbage.
I'm working with LWJGL.
Here's the code:
public static Ray getPick(int mouseX, int mouseY){
glPushMatrix();
//Setting up the Mouse Clip
Vector4f mouseClip = new Vector4f((float)mouseX * 2 / 960f - 1, 1 - (float)mouseY * 2 / 640f ,0 ,1);
//Loading Matrices
FloatBuffer modMatrix = BufferUtils.createFloatBuffer(16);
FloatBuffer projMatrix = BufferUtils.createFloatBuffer(16);
glGetFloat(GL_MODELVIEW_MATRIX, modMatrix);
glGetFloat(GL_PROJECTION_MATRIX, projMatrix);
//Assigning Matrices
Matrix4f proj = new Matrix4f();
Matrix4f model = new Matrix4f();
model.load(modMatrix);
proj.load(projMatrix);
//Multiplying the Projection Matrix by the Model View Matrix
Matrix4f tempView = new Matrix4f();
Matrix4f.mul(proj, model, tempView);
tempView.invert();
//Getting the Camera Position in World Space. The 4th Column of the Model View Matrix.
model.invert();
Point cameraPos = new Point(model.m30, model.m31, model.m32);
//Theoretically getting the vector the Picking Ray goes
Vector4f rayVector = new Vector4f();
Matrix4f.transform(tempView, mouseClip, rayVector);
rayVector.translate((float)-cameraPos.getX(),(float) -cameraPos.getY(),(float) -cameraPos.getZ(), 0f);
rayVector.normalise();
glPopMatrix();
//This Basically Spits out a value that changes as the Camera moves.
//When the Mouse moves, the values change around 0.001 points from screen edge to edge.
System.out.format("Vector: %f %f %f%n", rayVector.x, rayVector.y, rayVector.z);
//return new Ray(cameraPos, rayVector);
return null;
}
I don't really know why this isn't working. I was hoping some more experienced eyes might be able to help me out.
I can get the camera position like a champ, it's the vector the rays going in that I can't seem to get right.
Thanks.
