从零开始-边学边做-塔防游戏-七彩三国(九)--加载背景

第九章：加载背景

加载图片是游戏最基础的操作了。

我们先尝试加载一张图片，作为游戏背景显示出来。

这里我希望，游戏在不同分辨率下的手机，都可以看到一致的显示。并且显示尽可能最大化。

限定最小分辨率为 1024*768

if (g_SkyParkJni.getScreenWidth() < 1024|| g_SkyParkJni.getScreenHeight() < 768) {g_SkyparkLog.log("[%s][%d]Screen(%d*%d) < 1024*768", __FILE__, __LINE__,g_SkyParkJni.getScreenWidth(), g_SkyParkJni.getScreenHeight());exit(0);}

创建一个坐标转换体系。用来实现窗口自适应大小

C:\data\www\SanguoSDL\jni\skypark_game\SkyparkChange.hpp

#ifndef SKYPARKCHANGE_HPP_#define SKYPARKCHANGE_HPP_namespace skypark {class SkyparkChange {public:SkyparkChange() {m_iBaseWidth = 1366;m_iBaseHeight = 768;m_iPositionX = 0;m_iPositionY = 0;m_bRatio = false;m_iRatio = 1000;}void setWindowInfo(int iWidth, int iHeight) {m_iScreenWidth = iWidth;m_iScreenHeight = iHeight;if (m_iBaseWidth == iWidth && iHeight >= m_iBaseHeight) {m_iPositionY = (iHeight - m_iBaseHeight) / 2;m_iWindowWidth = m_iBaseWidth;m_iWindowHeight = m_iBaseHeight;return;}int fw = (iWidth * 1000 / m_iBaseWidth);int fh = (iHeight * 1000 / m_iBaseHeight);if (fw > fh) {fw = fh;m_iPositionX = (iWidth - m_iBaseWidth * fw / 1000) / 2;} else {m_iPositionY = (iHeight - m_iBaseHeight * fw / 1000) / 2;}m_bRatio = true;m_iRatio = fw;m_iWindowWidth = m_iBaseWidth * fw / 1000;m_iWindowHeight = m_iBaseHeight * fw / 1000;}public:int m_iBaseWidth; //游戏面板int m_iBaseHeight;int m_iScreenWidth; //手机屏幕int m_iScreenHeight;int m_iWindowWidth; //游戏面板在手机屏幕中的大小int m_iWindowHeight;int m_iPositionX; //游戏面板在手机屏幕中的位置int m_iPositionY;bool m_bRatio; //是否有缩放比例int m_iRatio; //缩放比例,千分之};}#endif /* SKYPARKCHANGE_HPP_ */

下面的代码实现游戏背景加载：

C:\data\www\SanguoSDL\jni\src\SanguoMain.cpp

#include <stdlib.h>#include <stdio.h>#include <time.h>#include <dirent.h>#include <jni.h>#include <android/asset_manager.h>#include <android/asset_manager_jni.h>#include "SDL_config.h"#include "SDL_test.h"#include "SDL.h"#include "SDL_image.h"#include "../skypark_game/skypark.h"using namespace skypark;//定义我的全局变量 --beginstatic SDL_Window * g_screen_window = NULL;static SDL_Renderer* g_screen_renderer = NULL;static skypark::SkyparkLog g_SkyparkLog;static skypark::SkyparkJni g_SkyparkJni;static skypark::SkyparkChange g_SkyparkChange;//定义我的全局变量 --end//初始化int skypark_sdl_init(char **argv) {int iRet = SDL_Init(SDL_INIT_EVERYTHING);if (iRet < 0) {return -1;}g_screen_window = SDL_CreateWindow("skypark", 0, 0,g_SkyparkJni.getScreenWidth(), g_SkyparkJni.getScreenHeight(),SDL_WINDOW_FULLSCREEN);if (g_screen_window == NULL) {return -2;}g_screen_renderer = SDL_CreateRenderer(g_screen_window, -1,SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);if (g_screen_renderer == NULL) {return -3;}g_SkyparkJni.setScreen(g_screen_window, g_screen_renderer);g_SkyparkChange.setWindowInfo(g_SkyparkJni.getScreenWidth(),g_SkyparkJni.getScreenHeight());return 0;}void ShowScreen(SDL_Texture * pSDL_Texture) {sleep(1);static Uint64 i = 0;i++;if (i % 10 == 0) {g_SkyparkLog.log("[%s][%d]run...", __FILE__, __LINE__);}if (g_screen_renderer == NULL) {return;}//设置颜色SDL_SetRenderDrawColor(g_screen_renderer, 0x00, 0x00, 0x00, 0xFF);//以上面的颜色擦除SDL_RenderClear(g_screen_renderer);//绘制背景SDL_Rect stPos;stPos.x = g_SkyparkChange.m_iPositionX;stPos.y = g_SkyparkChange.m_iPositionY;stPos.w = g_SkyparkChange.m_iWindowWidth;stPos.h = g_SkyparkChange.m_iWindowHeight;SDL_RenderCopy(g_screen_renderer, pSDL_Texture, NULL, &stPos);//绘制一个矩形SDL_Rect stRect;stRect.w = 100;stRect.h = 100;stRect.x = 1024 - stRect.w;stRect.y = 768 - stRect.h;SDL_SetRenderDrawColor(g_screen_renderer, 0x00, 0x00, 0xFF, 0xFF);SDL_RenderFillRect(g_screen_renderer, &stRect);//将缓存刷新到实际屏幕SDL_RenderPresent(g_screen_renderer);}#ifdef __cplusplusextern "C" {#endif//jni接口 --beginvoid Java_cn_skypark_sanguo_SanguoSDL_mySetAsset(JNIEnv* env, jclass tis,jobject assetManager) {AAssetManager * pAAssetManager = AAssetManager_fromJava(env, assetManager);g_SkyparkJni.setAAssetManager(env, pAAssetManager);}//jni接口 --end#ifdef __cplusplus}#endifint main(int argc, char *argv[]) {g_SkyparkLog.log("[%s][%d]begin w:%d h:%d f:%d", __FILE__, __LINE__,Android_ScreenWidth, Android_ScreenHeight, Android_ScreenFormat);int iRet = skypark_sdl_init(argv);g_SkyparkLog.log("[%s][%d]skypark_sdl_init = %d", __FILE__, __LINE__, iRet);if (g_SkyparkJni.getScreenWidth() < 1024|| g_SkyparkJni.getScreenHeight() < 768) {g_SkyparkLog.log("[%s][%d]Screen(%d*%d) < 1024*768", __FILE__, __LINE__,g_SkyparkJni.getScreenWidth(), g_SkyparkJni.getScreenHeight());exit(0);}//加载背景图片SDL_Surface * pSDL_Surface = g_SkyparkJni.getPic("pic/bg.png");if (pSDL_Surface == NULL) {g_SkyparkLog.log("[%s][%d]pSDL_Surface = null", __FILE__, __LINE__);exit(0);}g_SkyparkLog.log("[%s][%d]pic_w:%d pic_h:%d\n", __FILE__, __LINE__,pSDL_Surface->w, pSDL_Surface->h);SDL_Texture * pSDL_Texture = SDL_CreateTextureFromSurface(g_screen_renderer,pSDL_Surface);if (pSDL_Texture == NULL) {g_SkyparkLog.log("[%s][%d]pSDL_Texture = null", __FILE__, __LINE__);exit(0);}while (true) {//sleep(60);//g_SkyparkLog.log("[%s][%d]run...", __FILE__, __LINE__);ShowScreen(pSDL_Texture);}g_SkyparkLog.log("[%s][%d]end", __FILE__, __LINE__);return 0;}

真机测试如下：

附上项目代码：

http://download.csdn.net/detail/ycg01/6792211