osg学习（五十六）osg::State的AttributeMap作用

Posted 2022-02-10 hankern

记录当前状态机的所有StateAttribute，比如着色器、视口等。

osg/State
class OSG_EXPORT State : public Referenced

        typedef std::pair<const StateAttribute*,StateAttribute::OverrideValue>  AttributePair;
        typedef std::vector<AttributePair>                                      AttributeVec;
        struct AttributeStack
        
            AttributeStack()
            
                changed = false;
                last_applied_attribute = 0L;
                last_applied_shadercomponent = 0L;
                global_default_attribute = 0L;

            

            void print(std::ostream& fout) const;

            /** apply an attribute if required, passing in attribute and appropriate attribute stack */
            bool                    changed;
            const StateAttribute*   last_applied_attribute;
            const ShaderComponent*  last_applied_shadercomponent;
            ref_ptr<const StateAttribute> global_default_attribute;
            AttributeVec            attributeVec;
        ;
        typedef std::map<StateAttribute::TypeMemberPair,AttributeStack> AttributeMap;



osg/StateAttribute
class OSG_EXPORT StateAttribute : public Object

    typedef std::pair<Type,unsigned int> TypeMemberPair;