small chagnes to c core

src/map.c

@@ -209,8 +209,12 @@ static int map_object_texture(lua_State *L)
 static int map_object_shader(lua_State *L)
 {
 	map_object *obj = (map_object*)auxiliar_checkclass(L, "core{mapobj}", 1);
-	shader_type *s = (shader_type*)auxiliar_checkclass(L, "gl{program}", 2);
-	obj->shader = s;
+	if (!lua_isnil(L, 2)) {
+		shader_type *s = (shader_type*)auxiliar_checkclass(L, "gl{program}", 2);
+		obj->shader = s;
+	} else {
+		obj->shader = NULL;
+	}
 	return 0;
 }
 

src/particles.c

@@ -244,7 +244,6 @@ static void particles_draw(particles_type *ps, float x, float y, float zoom)
 
 	if (ps->shader) glUseProgramObjectARB(0);
 
-	glRotatef(-ps->rotate, 0, 0, 1);
 	glPopMatrix();
 	glTranslatef(-x, -y, 0);