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 := armeabi
APP_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 screen
const 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 := main
SDL_PATH := ../SDL
LOCAL_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.c
LOCAL_SHARED_LIBRARIES := SDL2
LOCAL_LDLIBS := -lGLESv1_CM -lGLESv2 -llog
include $(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: