我使用OpenTK在C中进行游戏,它不附带项目和未投影函数,它们在世界坐标和屏幕坐标之间转换。是的,但是他们被否决了,我不能让他们工作。我试过自己根据
opengl spec
(请参见左侧菜单,Glupproject和Glunproject,以及在FF中查看,而不是在Chrome中查看)。看看那些公式,我正在试着匹配它们。我的功能根本不起作用,项目返回的点都在我屏幕的中心附近,并且非常靠近,即使我正在将我的世界点移动到各处。
注意,opentk的math lib不包括将矩阵乘以向量的函数,所以我只是对结果向量中的每个条目进行矩阵行乘以向量点积(这是正确的,不是吗?)
public static Vector3d Project(Vector4d point, Matrix4d projection, Matrix4d modelview, int[] view)
{
Matrix4d temp = Matrix4d.Mult(projection, modelview);
// multiply matrix by vector
Vector4d v_prime = new Vector4d(
Vector4d.Dot(temp.Row0, point),
Vector4d.Dot(temp.Row1, point),
Vector4d.Dot(temp.Row2, point),
Vector4d.Dot(temp.Row3, point)
);
v_prime = Vector4d.Divide(v_prime, v_prime.W);
return new Vector3d(
view[0] + view[2] * (v_prime.X + 1) / 2,
view[1] + view[3] * (v_prime.Y + 1) / 2,
(v_prime.Z + 1) / 2
);
}
public static Vector3d UnProject(Vector3d window, Matrix4d modelview, Matrix4d projection, int[] view)
{
Matrix4d inv = Matrix4d.Mult(projection, modelview);
inv.Invert();
double vx = (2 * (window.X - view[0])) / view[2] - 1;
double vy = (2 * (window.Y - view[1])) / view[3] - 1;
double vz = (2 * window.Z) - 1;
Vector4d vect = new Vector4d(vx, vy, vz, 1);
// now multiply matrix times vector, which is really row (dot) vector for each value
// correct, the bottom row of the inv matrix is unused
return new Vector3d(
Vector4d.Dot(inv.Row0, vect),
Vector4d.Dot(inv.Row1, vect),
Vector4d.Dot(inv.Row2, vect)
);
}