diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..616612c
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,2 @@
+*.pdf linguist-detectable=false
+*.tm linguist-detectable=false
diff --git a/LightRays.xcodeproj/project.pbxproj b/LightRays.xcodeproj/project.pbxproj
index cfd0d6e..114762c 100644
--- a/LightRays.xcodeproj/project.pbxproj
+++ b/LightRays.xcodeproj/project.pbxproj
@@ -10,6 +10,7 @@
 		022C25F6239ADF4400E2D35D /* Source.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 022C25F4239ADF4400E2D35D /* Source.cpp */; };
 		026842D323D727A70023E614 /* ObjetDiffusant.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 026842D123D727A70023E614 /* ObjetDiffusant.cpp */; };
 		02862264240ED9750000A6ED /* Scene.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 02F319B423DA713B0059D3AF /* Scene.cpp */; };
+		02A50045242ADE2000252D54 /* main_diffus_test.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 02B2BEE523FEAF75009FDF7F /* main_diffus_test.cpp */; };
 		02AEC71D23F2CB8900816C72 /* ObjetsOptiques.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 02AEC71B23F2CB8900816C72 /* ObjetsOptiques.cpp */; };
 		02B2BEE923FF44B8009FDF7F /* SceneTest.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 02B2BEE723FF44B8009FDF7F /* SceneTest.cpp */; };
 		02C0BBF923F99485006F99C7 /* Brouillard.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 02C0BBF723F99485006F99C7 /* Brouillard.cpp */; };
@@ -220,6 +221,7 @@
 				02C0BBF923F99485006F99C7 /* Brouillard.cpp in Sources */,
 				02D1B5972376EC0E00B7FC13 /* Rayon.cpp in Sources */,
 				02B2BEE923FF44B8009FDF7F /* SceneTest.cpp in Sources */,
+				02A50045242ADE2000252D54 /* main_diffus_test.cpp in Sources */,
 				02D1B59A2377242B00B7FC13 /* Util.cpp in Sources */,
 				02AEC71D23F2CB8900816C72 /* ObjetsOptiques.cpp in Sources */,
 			);
diff --git a/LightRays/sfml_c01.hpp b/LightRays/sfml_c01.hpp
index 69f67ea..18f3d5e 100644
--- a/LightRays/sfml_c01.hpp
+++ b/LightRays/sfml_c01.hpp
@@ -1,15 +1,18 @@
 #include <SFML/Graphics.hpp>
 #include <string>
+#ifndef SFMLC01_WINDOW_HEIGHT
+#define SFMLC01_WINDOW_HEIGHT SFMLC01_WINDOW_UNIT
+#endif
 
 namespace sf { namespace c01 {
 	
 	inline sf::Vector2f toWin (pt2_t p) {
-		return sf::Vector2f( p.x*SFMLC01_WINDOW_UNIT, (1.f-p.y)*SFMLC01_WINDOW_UNIT );
+		return sf::Vector2f( p.x*SFMLC01_WINDOW_UNIT, SFMLC01_WINDOW_HEIGHT-p.y*SFMLC01_WINDOW_UNIT );
 	}
 	
 	inline void setCircleCR (sf::CircleShape& circle, pt2_t c, float r) {
 		circle.setRadius(r*SFMLC01_WINDOW_UNIT);
-		circle.setPosition( (c.x-r)*SFMLC01_WINDOW_UNIT, (1.f-c.y-r)*SFMLC01_WINDOW_UNIT );
+		circle.setPosition( (c.x-r)*SFMLC01_WINDOW_UNIT, SFMLC01_WINDOW_HEIGHT-(c.y+r)*SFMLC01_WINDOW_UNIT );
 	}
 	inline sf::CircleShape buildCircleShapeCR (pt2_t c, float r) {
 		sf::CircleShape circle; sf::c01::setCircleCR(circle, c, r); return circle;