cocos2d-xの画面サイズをいい感じに設定するユーティリティ

GLViewUtil.h

//
//  GLViewUtil.h
//
//  Created by kyokomi on 2014/10/28.
//
//

#ifndef KyokomiDemo_GLViewUtil_h
#define KyokomiDemo_GLViewUtil_h

#include "base/CCDirector.h"
#include "platform/CCGLView.h"

namespace GLViewUtil {

    enum class FitType {
        WIDTH,
        HEIGHT,
    };
    
    cocos2d::Size calcFitDesignResolutionSize(float width, float height, FitType fitType, float scale = 1.0f)
    {
        auto visibleSize = cocos2d::Director::getInstance()->getVisibleSize();
        
        float baseScaleWidth  = width * scale;
        float baseScaleHeight = height * scale;
        
        int widthDiff = abs((int)visibleSize.width - (int)width);
        int heightDiff = abs((int)visibleSize.height - (int)height);
        
        if (widthDiff == 0 && heightDiff == 0) {
            return cocos2d::Size(baseScaleWidth, baseScaleHeight);
        }
        
        float divX = visibleSize.width / baseScaleWidth;
        float divY = visibleSize.height / baseScaleHeight;
        float fixWidth = widthDiff / divY;
        float fixHeight = heightDiff / divX;
        if (fitType == FitType::HEIGHT) {
            // 縦優先
            float addWidth = (heightDiff / divY * (width / height));
            return cocos2d::Size(baseScaleWidth + fixWidth - addWidth, baseScaleHeight);
        } else {
            // 横優先
            float addheight = (widthDiff / divX * (height / width));
            return cocos2d::Size(baseScaleWidth, baseScaleHeight + fixHeight - addheight);
        }
    }

    cocos2d::Size getFitDesignResolutionSize(float width, float height, FitType fitType, float scale = 1.0f)
    {
        cocos2d::Size fitSize = GLViewUtil::calcFitDesignResolutionSize(width, height, FitType::WIDTH, scale);
        
        float baseScaleWidth  = width * scale;
        float baseScaleHeight = height * scale;
        
        if (fitType == FitType::HEIGHT && fitSize.width < baseScaleWidth) {
            return GLViewUtil::calcFitDesignResolutionSize(width, height, FitType::WIDTH, scale);
        } else if (fitType == FitType::WIDTH && fitSize.height < baseScaleHeight) {
            return GLViewUtil::calcFitDesignResolutionSize(width, height, FitType::HEIGHT, scale);
        }
        return fitSize;
    }
}

#endif

使い方

AppDelegate.cpp

#include "AppDelegate.h"
#include "GLViewUtil.h"

USING_NS_CC;

// 〜省略〜

bool AppDelegate::applicationDidFinishLaunching() {
    // initialize director
    auto director = Director::getInstance();
    auto glview = director->getOpenGLView();
    if(!glview) {
        glview = GLViewImpl::create("My Game");
        director->setOpenGLView(glview);
    }

    // turn on display FPS
    director->setDisplayStats(true);

    // set FPS. the default value is 1.0/60 if you don't call this
    director->setAnimationInterval(1.0 / 60);

    // ★640x960にフィットした画面にする（縦横の黒棒なし）
    auto fitSize = GLViewUtil::getFitDesignResolutionSize(640, 960);
    glview->setDesignResolutionSize(fitSize.width, fitSize.height, ResolutionPolicy::SHOW_ALL);

    // create a scene. it's an autorelease object
    auto scene = HelloWorld::createScene();

    // run
    director->runWithScene(scene);

    return true;
}

// 〜省略〜