From: Alexis Laferrière <alexis.laf@xymus.net>
Date: Sat, 22 Apr 2017 17:52:40 +0000 (-0400)
Subject: gamnit: intro cache for `Camera::mvp_matrix`
X-Git-Url: http://nitlanguage.org

gamnit: intro cache for `Camera::mvp_matrix`

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

diff --git a/lib/gamnit/cameras.nit b/lib/gamnit/cameras.nit
index 401e1ce..c9754f7 100644
--- a/lib/gamnit/cameras.nit
+++ b/lib/gamnit/cameras.nit
@@ -264,7 +264,7 @@ class UICamera
 	# Bottom right corner of the screen, at z = 0
 	fun bottom_right: Point3d[Float] do return new Point3d[Float](position.x + width, position.y - height, 0.0)
 
-	# TODO cache the anchors and the matrix
+	# TODO cache the anchors
 
 	redef fun mvp_matrix
 	do
diff --git a/lib/gamnit/cameras_cache.nit b/lib/gamnit/cameras_cache.nit
new file mode 100644
index 0000000..08adc8f
--- /dev/null
+++ b/lib/gamnit/cameras_cache.nit
@@ -0,0 +1,124 @@
+# This file is part of NIT ( http://www.nitlanguage.org ).
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Cache the `Matrix` produced by `Camera::mvp_matrix`
+module cameras_cache
+
+import cameras
+
+redef class Camera
+	private var mvp_matrix_cache: nullable Matrix = null
+
+	private var position_cache = new Point3d[Float](0.0, 0.0, 0.0)
+
+	# Has `position` changed from `position_cache`? Update the cache at the same time
+	private fun check_position_changed: Bool
+	do
+		if position.x != position_cache.x or
+		   position.y != position_cache.y or
+		   position.z != position_cache.z then
+			position_cache.x = position.x
+			position_cache.y = position.y
+			position_cache.z = position.z
+			return true
+		end
+		return false
+	end
+end
+
+redef class EulerCamera
+	# The returned matrix must not be modified as it is cached.
+	redef fun mvp_matrix
+	do
+		var m = mvp_matrix_cache
+		if m == null or check_position_changed then
+			m = super
+			mvp_matrix_cache = m
+		end
+		return m
+	end
+
+	redef fun pitch=(value)
+	do
+		super
+		mvp_matrix_cache = null
+	end
+
+	redef fun yaw=(value)
+	do
+		super
+		mvp_matrix_cache = null
+	end
+
+	redef fun roll=(value)
+	do
+		super
+		mvp_matrix_cache = null
+	end
+
+	redef fun field_of_view_y=(value)
+	do
+		super
+		mvp_matrix_cache = null
+	end
+
+	redef fun near=(value)
+	do
+		super
+		mvp_matrix_cache = null
+	end
+
+	redef fun far=(value)
+	do
+		super
+		mvp_matrix_cache = null
+	end
+end
+
+redef class UICamera
+	# The returned matrix must not be modified as it is cached.
+	redef fun mvp_matrix
+	do
+		var m = mvp_matrix_cache
+		if m == null or check_position_changed then
+			m = super
+			mvp_matrix_cache = m
+		end
+		return m
+	end
+
+	redef fun near=(value)
+	do
+		super
+		mvp_matrix_cache = null
+	end
+
+	redef fun far=(value)
+	do
+		super
+		mvp_matrix_cache = null
+	end
+
+	redef fun width=(value)
+	do
+		super
+		mvp_matrix_cache = null
+	end
+
+	redef fun height=(value)
+	do
+		super
+		mvp_matrix_cache = null
+	end
+end
diff --git a/lib/gamnit/flat.nit b/lib/gamnit/flat.nit
index cfd8150..d5d2ef1 100644
--- a/lib/gamnit/flat.nit
+++ b/lib/gamnit/flat.nit
@@ -40,7 +40,7 @@ import more_collections
 import performance_analysis
 
 import gamnit
-import gamnit::cameras
+import gamnit::cameras_cache
 import gamnit::dynamic_resolution
 import gamnit::limit_fps
 import gamnit::camera_control