cocos2d-lua gl.clearColor（r,g,b,a）这4个参数本应该传递之间任意数，可是传比如r=0.9 最终传递的是r=0
找到该函数的lua绑定接口
在LuaOpengl.cpp的static int tolua_Cocos2d_glClearColor00(lua_State* tolua_S)函数里
unsigned int red = (unsigned int)tolua_tonumber(tolua_S,1,0);
unsigned int green = (unsigned int)tolua_tonumber(tolua_S,2,0);
unsigned int blue = (unsigned int)tolua_tonumber(tolua_S,3,0);
unsigned int alpha = (unsigned int)tolua_tonumber(tolua_S,4,0);
glClearColor((GLclampf)red , (GLclampf)green , (GLclampf)blue , (GLclampf)alpha);
(unsigned int)为毛要强转成int！