matrix: cache the last `gamnit_euler_rotation` matrix created

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>

diff --git a/lib/matrix/projection.nit b/lib/matrix/projection.nit
index a9bf8b8..368ef11 100644 (file)
--- a/lib/matrix/projection.nit
+++ b/lib/matrix/projection.nit
@@ -159,18 +159,43 @@ redef class Matrix
        #
        # This service aims to respect the world axes and logic of `gamnit`,
        # it may not correspond to all needs.
+       #
+       # The returned `Matrix` may be cached, it must not be modified.
        new gamnit_euler_rotation(pitch, yaw, roll: Float)
        do
+               if pitch == 0.0 and yaw == 0.0 and roll == 0.0 then
+                       return once new Matrix.identity(4)
+               end
+
+               if rotation_pitch == pitch and rotation_yaw == yaw and rotation_roll == roll then
+                       var rot = rotation_matrix_cache
+                       if rot != null then return rot
+               end
+
                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(
+               var rot = 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]])
+
+               rotation_matrix_cache = rot
+               rotation_pitch = pitch
+               rotation_yaw = yaw
+               rotation_roll = roll
+               return rot
        end
 end
+
+redef class Sys
+
+       private var rotation_matrix_cache: nullable Matrix = null
+       private var rotation_pitch = 0.0
+       private var rotation_yaw = 0.0
+       private var rotation_roll = 0.0
+end