gamnit: 3 Euler rotation angles for actors

[nit.git] / lib / matrix / projection.nit

diff --git a/lib/matrix/projection.nit b/lib/matrix/projection.nit
index 908761a..a9bf8b8 100644 (file)
--- a/lib/matrix/projection.nit
+++ b/lib/matrix/projection.nit
@@ -150,4 +150,27 @@ redef class Matrix
                var rotated = self * rotation
                self.items = rotated.items
        end
+
+       # Rotation matrix from Euler angles `pitch`, `yaw` and `roll` in radians
+       #
+       # Apply a composition of intrinsic rotations around the axes x-y'-z''.
+       # Or `pitch` around the X axis, `yaw` around Y and `roll` around Z,
+       # applied successively. All rotations follow the right hand rule.
+       #
+       # This service aims to respect the world axes and logic of `gamnit`,
+       # it may not correspond to all needs.
+       new gamnit_euler_rotation(pitch, yaw, roll: Float)
+       do
+               var c1 = pitch.cos
+               var s1 = pitch.sin
+               var c2 = yaw.cos
+               var s2 = yaw.sin
+               var c3 = roll.cos
+               var s3 = roll.sin
+               return new Matrix.from(
+                       [[          c2*c3,          -c2*s3,   -s2, 0.0],
+                        [ c1*s3+c3*s1*s2,  c1*c3-s1*s2*s3, c2*s1, 0.0],
+                        [-s1*s3+c1*c3*s2, -c3*s1-c1*s2*s3, c1*c2, 0.0],
+                        [            0.0,             0.0,   0.0, 1.0]])
+       end
 end