gamnit: cache the light mvp_matrix

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

diff --git a/lib/gamnit/depth/more_lights.nit b/lib/gamnit/depth/more_lights.nit
index 7637e02..3512f27 100644 (file)
--- a/lib/gamnit/depth/more_lights.nit
+++ b/lib/gamnit/depth/more_lights.nit
@@ -16,6 +16,7 @@
 module more_lights
 
 import depth_core
+intrude import cameras_cache
 
 # TODO
 #class PointLight
@@ -57,10 +58,8 @@ private class ParallelLightCamera
                return view
        end
 
-       redef fun mvp_matrix
+       private fun create_mvp_matrix: Matrix
        do
-               # TODO cache
-
                var near = -light.depth/2.0
                var far = light.depth/2.0
 
@@ -72,4 +71,40 @@ private class ParallelLightCamera
                                                       near, far)
                return view * projection
        end
+
+       redef fun mvp_matrix
+       do
+               var m = mvp_matrix_cache
+               if m == null or check_position_changed then
+                       m = create_mvp_matrix
+                       mvp_matrix_cache = m
+               end
+               return m
+       end
+
+       private var pitch_cache = 0.0
+       private var yaw_cache = 0.0
+       private var width_cache = 0.0
+       private var height_cache = 0.0
+       private var depth_cache = 0.0
+
+       redef fun check_position_changed
+       do
+               if super then return true
+
+               if light.pitch != pitch_cache or
+                  light.yaw != yaw_cache or
+                  light.width != width_cache or
+                  light.height != height_cache or
+                  light.depth != depth_cache then
+                       pitch_cache = light.pitch
+                       yaw_cache = light.yaw
+                       width_cache = light.width
+                       height_cache = light.height
+                       depth_cache = light.depth
+                       return true
+               end
+
+               return false
+       end
 end