首页 > 代码库 > [原]零基础学习SDL开发之在Android使用SDL2.0显示BMP图
[原]零基础学习SDL开发之在Android使用SDL2.0显示BMP图
关于如何移植SDL2.0到安卓上面来参考我的上一篇文章：[原]零基础学习SDL开发之移植SDL2.0到Android
在一篇文章我们主要使用SDL2.0来加载一张BMP图来渲染显示。
博主的开发环境：Ubuntu 14.04 64位，Eclipse + CDT + ADT+NDK
博主曾经自己使用NDK编译出了libSDL2.so，然后使用共享库的方式来调用libSDL2中的函数，结果发现SDL\src\core\android\SDL_android.c 这个jni函数写的实在是不够自己另外做移植用，与org.libsdl.app.SDLActivity耦合太紧密了。如果想使用共享库的方式去调用SDL中的函数，最好自己去写JNI注册与调用函数实现。
一、导入SDL源码
还是把SDL源码中的android-project工程导入到Eclipse中来，进入jni文件夹，新建一个SDL文件，将SDL2-2.0.3\src 、SDL2-2.0.3\include、SDL2-2.0.3\Android.mk文件拷贝到android-project\jni\SDL\中。
在android-project中新建Android.mk,内容如下：
include $(call all-subdir-makefiles)
在android-project中新建Application.mk,内容如下：
APP_ABI := armeabiAPP_PLATFORM := android-9
二、新建功能模块
在jni下新建一文件夹src，新建SDL_logger.h，用来使用android中的log来打印日志，内容如下：
/* * log.h * * Created on: Aug 8, 2014 * Author: clarck */#ifndef LOG_H_#define LOG_H_#include <android/log.h>#define APPNAME "SDL_Lesson"#define LOGV(...) __android_log_print(ANDROID_LOG_VERBOSE, APPNAME, __VA_ARGS__)#define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG , APPNAME, __VA_ARGS__)#define LOGI(...) __android_log_print(ANDROID_LOG_INFO , APPNAME, __VA_ARGS__)#define LOGW(...) __android_log_print(ANDROID_LOG_WARN , APPNAME, __VA_ARGS__)#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR , APPNAME, __VA_ARGS__)#endif /* LOG_H_ */
新建SDL_lesson.c，用来使用SDL window的创建，加载bmp，渲染图片的功能，具体内容：
/* * SDL_lesson.c * * Created on: Aug 8, 2014 * Author: clarck */#ifdef __ANDROID__#include <jni.h>#include "SDL.h"#include "SDL_log.h"#include "SDL_main.h"//The attributes of the screenconst int SCREEN_WIDTH = 640;const int SCREEN_HEIGHT = 480;const int SCREEN_BPP = 32;struct SDL_Window *window = NULL;struct SDL_Renderer *render = NULL;struct SDL_Surface *bmp = NULL;struct SDL_Texture *texture = NULL;int main(int argc, char *argv[]) { char *filepath = argv[1]; LOGI("natvie_SDL %s", filepath); if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER) == -1) { LOGE("SDL_Init failed %s", SDL_GetError()); } LOGI("SDL_CreateWindow"); window = SDL_CreateWindow("Hello World!", 100, 100, 640, 480, SDL_WINDOW_SHOWN); if (window == NULL) { LOGE("SDL_CreateWindow failed %s", SDL_GetError()); } LOGI("SDL_CreateRenderer"); render = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC); if (render == NULL) { LOGE("SDL_CreateRenderer failed %s", SDL_GetError()); } bmp = SDL_LoadBMP(filepath); if (bmp == NULL) { LOGE("SDL_LoadBMP failed: %s", SDL_GetError()); } texture = SDL_CreateTextureFromSurface(render, bmp); SDL_FreeSurface(bmp); SDL_RenderClear(render); SDL_RenderCopy(render, texture, NULL, NULL); SDL_RenderPresent(render); SDL_Delay(2000); SDL_DestroyTexture(texture); SDL_DestroyRenderer(render); SDL_DestroyWindow(window); //Quit SDL SDL_Quit(); return 0;}#endif /* __ANDROID__ */
在src下编写Android.mk，用来编译SDL_lesson.c，内容如下：
LOCAL_PATH := $(call my-dir)include $(CLEAR_VARS)LOCAL_MODULE := mainSDL_PATH := ../SDLLOCAL_C_INCLUDES := $(LOCAL_PATH)/$(SDL_PATH)/include# Add your application source files here...LOCAL_SRC_FILES := $(SDL_PATH)/src/main/android/SDL_android_main.c SDL_Lesson.cLOCAL_SHARED_LIBRARIES := SDL2LOCAL_LDLIBS := -lGLESv1_CM -lGLESv2 -lloginclude $(BUILD_SHARED_LIBRARY)
三、修改SDLActivity、SDL\src\main\SDL_android_main.c以便接受传入的参数：
修改SDLActivity中的 SDLMain类，修改内容如下：
/** Simple nativeInit() runnable*/class SDLMain implements Runnable { @Override public void run() { // Runs SDL_main() String sdcard = Environment.getExternalStorageDirectory().getAbsolutePath(); SDLActivity.nativeInit(sdcard + File.separator + "hello.bmp"); //Log.v("SDL", "SDL thread terminated"); }}
修改SDL\src\main\SDL_android_main.c，修改如下：
/* SDL_android_main.c, placed in the public domain by Sam Lantinga 3/13/14*/#include "../../SDL_internal.h"#ifdef __ANDROID__/* Include the SDL main definition header */#include "SDL_main.h"/******************************************************************************* Functions called by JNI*******************************************************************************/#include <jni.h>/* Called before SDL_main() to initialize JNI bindings in SDL library */extern void SDL_Android_Init(JNIEnv* env, jclass cls);char* jstringTostr(JNIEnv* env, jstring jstr) { char* pStr = NULL; jclass jstrObj = (*env)->FindClass(env, "java/lang/String"); jstring encode = (*env)->NewStringUTF(env, "utf-8"); jmethodID methodId = (*env)->GetMethodID(env, jstrObj, "getBytes", "(Ljava/lang/String;)[B"); jbyteArray byteArray = (jbyteArray) (*env)->CallObjectMethod(env, jstr, methodId, encode); jsize strLen = (*env)->GetArrayLength(env, byteArray); jbyte *jBuf = (*env)->GetByteArrayElements(env, byteArray, JNI_FALSE); if (jBuf > 0) { pStr = (char*) malloc(strLen + 1); if (!pStr) { return NULL ; } memcpy(pStr, jBuf, strLen); pStr[strLen] = 0; } (*env)->ReleaseByteArrayElements(env, byteArray, jBuf, 0); return pStr;}/* Start up the SDL app */void Java_org_libsdl_app_SDLActivity_nativeInit(JNIEnv* env, jclass cls, jobject obj){ /* This interface could expand with ABI negotiation, calbacks, etc. */ SDL_Android_Init(env, cls); SDL_SetMainReady(); char *filePath = jstringTostr(env, obj); /* Run the application code! */ int status; char *argv[2]; argv[0] = SDL_strdup("SDL_app"); argv[1] = filePath; status = SDL_main(1, argv); /* Do not issue an exit or the whole application will terminate instead of just the SDL thread */ /* exit(status); */}#endif /* __ANDROID__ *//* vi: set ts=4 sw=4 expandtab: */
最后，上一张运行的截图：
声明：以上内容来自用户投稿及互联网公开渠道收集整理发布，本网站不拥有所有权，未作人工编辑处理，也不承担相关法律责任，若内容有误或涉及侵权可进行投诉： 投诉/举报 工作人员会在5个工作日内联系你，一经查实，本站将立刻删除涉嫌侵权内容。