/**
* Project a world point through the matrix to get its screen position.
*
* @param world the point to project
* @return its screen position
*/
@Nullable
public Vec2i project(@NotNull Vec3f world) {
Vec4f vec = Matrix.mul(getPmvMatrix(), new Vec4f(world, 1.0f));
Vec2i screen = null;
if (vec.getW() != 0.0f) {
double z = vec.getZ() / vec.getW();
if (z < 1) {
int x = (int) ((vec.getX() / vec.getW() * 0.5 + 0.5) * viewport.getWidth());
int y =
(int)
(viewport.getHeight()
- (vec.getY() / vec.getW() * 0.5 + 0.5) * viewport.getHeight());
screen = new Vec2i(x, y);
}
}
return screen;
}
/** Transforms a pixel in window coordinates to a ray in world coordinates. */
public static Ray windowToWorld(Camera camera, Viewport viewport, Point windowCoords) {
Vec2f ndc = viewport.windowToNDC(windowCoords);
Vec4f n =
camera
.getViewInverse()
.times(camera.getProjectionInverse().times(new Vec4f(ndc.x, ndc.y, -1, 1)));
n.divide(n.w);
Vec4f f =
camera
.getViewInverse()
.times(camera.getProjectionInverse().times(new Vec4f(ndc.x, ndc.y, 1, 1)));
f.divide(f.w);
return new Ray(n.xyz(), f.minus(n).xyz().normalized());
}
/** Transforms a point in world coordinates to a pixel in window coordinates. */
public static Point worldToWindow(Camera camera, Viewport viewport, Vec3f worldCoords) {
Vec4f clip = camera.getProjection().times(camera.getView().times(new Vec4f(worldCoords, 1)));
Vec2f ndc = clip.over(clip.w).xy();
return viewport.ndcToWindow(ndc);
}
