Are you using the template keyword?

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#1

Hi,
Are some of you using the template keyword and if yes, when/for what? I mean I have never really encountered the need of using it for game development…

#2

Yes there are many use case for that, for example a prefab made just to serve the purpose of a template. Like you have a consumable item prefab as a template, extra configuration on top will need to be made during runtime such as changing certain label strings.

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#3

thanks for the quick reply! But can you give an example of a “consumable item prefab as a template” because I do not know if I get what you mean by that. :slight_smile:

#4

This pice of code creates autorelease cocos object with arguments forwarding to constructor. That allows me to not write ‘create’ static method in each coocs2d child class

#pragma once
#ifndef COCOS_HELPER_HPP
#define COCOS_HELPER_HPP

#include <type_traits>

namespace app { namespace util {
	/*
		Create autorelease cocos object

		@note T must be derived from cocos2d::Ref
		@param args [optional] arguments that forwards to T constructor
		@return autorelease object
	*/
	template<typename T, typename... Args>
	inline T* make_autorelease( Args&&... args )noexcept {
		static_assert( std::is_base_of<cocos2d::Ref, T>::value,
						"T must be derived from cocos2d::Ref" );

		auto pRet = new( std::nothrow ) T{ std::forward<Args>( args )... };
		if ( pRet && pRet->init( ) ) {
			pRet->autorelease( );
			return pRet;
		} else {
			delete pRet;
			pRet = nullptr;
			return nullptr;
		}
	}
} }
#endif
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#5

Thank you. Fantastic with an example :slight_smile:

#6

You could also use templates for container class that could have many type parameters on it

class Vector {
private:
    std::array<T, size> data;

public:
    Vector() : Vector<T, size>(T(0)) {}

    Vector(T value) {
        for (int i = 0; i < size; ++i) {
            data[i] = value;
        }
    }

    Vector(std::array<T, size> data) {
        this->data = data;
    }

    template<typename scalar>
    Vector<T, size>& multiply(scalar factor) {
        for (int i = 0; i < size; ++i) {
            data[i] *= factor;
        }
        return *this;
    }
}

with this you could easily use a vector of int or vector of floats, etc