[NDK] JNI 中编译两个库文件。

╰半橙微兮° 2022-09-19 00:26 211阅读 0赞

在NDK的例子中有这个例子，先编译出一个静态库，再编译出动态库并引用之前的静态库。其他部分一样，在jni目录下，

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1. 之前一直定义不了GLfloat 数组，现在发现，因为MyRendererNative.h头文件会被com\_example\_nativeegl\_MyRenderer.h文件引用。所以在其中定义数组会有问题。数组应该直接在MyRendererNative.cpp中声明定义。

如果头文件不被引用的话，直接在.h文件中声明就可以。

Hello.h
    #include <iostream>
    using namespace std;
    class Hello {
    int test[] = {1,2,3,4};  //Its ok because Hello.h没被引用
    };

The Android.mk file content:

#Description:makefile of Helloworld  
    LOCAL_PATH := $(call my-dir)
    #=======================
    include $(CLEAR_VARS)
    
    LOCAL_CFLAGS    := -Wall
    
    LOCAL_MODULE    := libmyegl_impl
    
    LOCAL_CPP_EXTENSION := .cpp
    
    #local_ldlibs is used for system libs and does not need dependency
    LOCAL_LDLIBS += -llog -lGLESv1_CM
    
    LOCAL_SHARED_LIBRARIES += libcutils libutils
    
    LOCAL_C_INCLUDES := \
    		$(LOCAL_PATH)/include 
    LOCAL_SRC_FILES := \
    		MyRendererNative.cpp
    
    LOCAL_CFLAGS:= -DLOG_TAG=\"MyRender\"
    
    #include $(BUILD_SHARED_LIBRARY)
    include $(BUILD_STATIC_LIBRARY)
    
    #========================
    
    include $(CLEAR_VARS)
    LOCAL_CFLAGS    := -Wall
    
    LOCAL_MODULE    := myegl_jni
    
    LOCAL_C_INCLUDES := \
    		$(LOCAL_PATH)/include 
    
    LOCAL_CPP_EXTENSION := .cpp
    
    LOCAL_LDLIBS += -llog -lGLESv1_CM
    
    #LOCAL_SHARED_LIBRARIES += libmyegl_impl  
    LOCAL_STATIC_LIBRARIES := libmyegl_impl
    
    LOCAL_SRC_FILES := \
        com_example_nativeegl_MyRenderer.cpp 
    
    include $(BUILD_SHARED_LIBRARY)
    
    # Use the folloing include to make our test apk.
    #include $(call all-makefiles-under,$(LOCAL_PATH))

com\_example\_nativeegl\_MyRenderer.h

#include <jni.h>
    #include <string.h>
    #include <android/log.h>
    #include <GLES/gl.h>
    #include <GLES/glext.h>
    #include <stdio.h>
    #include <stdlib.h>
    #include <math.h>
    #include <MyRendererNative.h>
    
    extern "C" {
    #define  LOG_TAG    "libgl_jni"
    #define  LOGI(...)  __android_log_print(ANDROID_LOG_INFO,LOG_TAG,__VA_ARGS__)
    #define  LOGE(...)  __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,__VA_ARGS__)
    #define  LOGD(...)  __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,__VA_ARGS__)
    
    MyRenderer* myRenderer;
    } //end of extern "C"

cpp file

#include "com_example_nativeegl_MyRenderer.h"
    
    extern "C" {
    /*
     * Class:     com_example_nativeegl_MyRenderer
     * Method:    nativeGetHelloString
     * Signature: ()Ljava/lang/String;
     */
    jstring  nativeGetHelloString(JNIEnv *env, jobject obj) {
          return env->NewStringUTF((char*)" This is calling from JNI suckers!");
      }
    
    /*
     * Class:     com_example_nativeegl_MyRenderer
     * Method:    nativeDrawFrame
     * Signature: ()V
     */
    void nativeDrawFrame(JNIEnv *env, jobject obj) {
    	myRenderer->renderFrame();
    }
    
    /*
     * Class:     com_example_nativeegl_MyRenderer
     * Method:    nativeSurfaceChanged
     * Signature: (II)V
     */
    void nativeSurfaceChanged(JNIEnv *env, jobject obj, jint width, jint height){
    	myRenderer->resize(width, height);
    }
    
    
    /*
     * Class:     com_example_nativeegl_MyRenderer
     * Method:    nativeSurfaceCreated
     * Signature: ()V
     */
     void nativeSurfaceCreated(JNIEnv *env, jobject obj) {
    	 myRenderer = new MyRenderer();
    	 myRenderer->init();
     }
    
    //----------------------------JNI part:Native register------------------------------------------------------
    static JNINativeMethod gMethods[] = {
    		//{"native method name from Java","(arguments type)return type", "(void*)local_native_name"
    		{"nativeGetHelloString", "()Ljava/lang/String;", (void *)nativeGetHelloString},
    		{"nativeDrawFrame", "()V", (void *)nativeDrawFrame},
    		{"nativeSurfaceChanged", "(II)V", (void *)nativeSurfaceChanged},
    		{"nativeSurfaceCreated", "()V", (void *)nativeSurfaceCreated},
    };
    
    static const char* className="com/example/nativeegldynamicjni/MyRenderer";
    
    static int registerNativeMethods(JNIEnv *env) {
    	jclass clazz;
    	clazz = env->FindClass(className);
    	if (clazz == NULL) {
    		LOGD("failed to load the class %s", className);
    		return JNI_FALSE;
    	}
    	if (env->RegisterNatives(clazz, gMethods, sizeof(gMethods)/sizeof(gMethods[0])) < 0) {
    		return JNI_FALSE;
    	}
    	return JNI_TRUE;
    } //end of registerNativeMethods
    
    jint JNI_OnLoad(JavaVM* vm, void* reserved) {
    	JNIEnv* env = NULL;
    	jint result = -1;
    	if (vm->GetEnv((void**) &env, JNI_VERSION_1_4) != JNI_OK)
    	{
    		LOGE("ERROR: GetEnv failed\n");
    		goto bail;
    	}
    
    	if (registerNativeMethods(env) < 0) {
    		LOGE("ERROR: jnitest native registration failed\n");
    		goto bail;
    	}
    	result = JNI_VERSION_1_4;
    
    	bail:
    	return result;
    }
    
    } //end of extern "C"

MyRendererNative.h

#include <string.h>
    #include <GLES/gl.h>
    #include <GLES/gl.h>
    #include <GLES/glext.h>
    #include <stdio.h>
    #include <stdlib.h>
    #include <math.h>
    #include <android/log.h>
    
    #define  LOG_TAG    "libgl_impl"
    #define  LOGI(...)  __android_log_print(ANDROID_LOG_INFO,LOG_TAG,__VA_ARGS__)
    #define  LOGE(...)  __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,__VA_ARGS__)
    #define  LOGD(...)  __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,__VA_ARGS__)
    
    class MyRenderer {
    private:
    	GLfloat rtri;  //三角形的旋转变量
    	GLfloat rquad;  //四边形的旋转变量
    	int testintprivate;   //non-static variable need to be initialised in constructor method
    
    public:
    	static const GLfloat PI = 3.1415f;
    	static int testintpublic;
    
    public:
    	MyRenderer();
    	virtual ~MyRenderer();
    
    	void printGLString(char* name, GLenum s);
    	void init();
    	void resize(int width, int height);
    	void gluPerspective(GLfloat fovy, GLfloat aspect, GLfloat zNear, GLfloat zFar);
    	void renderFrame();
    };

cpp file

#include "MyRendererNative.h"
    
    MyRenderer::MyRenderer():testintprivate(0) {
    }
    
    MyRenderer::~MyRenderer() {
    
    }
    
    int testintpublic = 12;   //static variable initialisation.
    
    void MyRenderer::printGLString(char* name, GLenum s) {
    	char *v = (char *) glGetString(s);
    	LOGI("GL %s = %s", name, v);
    }
    
    void MyRenderer::init() {
    	LOGD("init the renderer");
    	rtri= 0;
    	glShadeModel(GL_SMOOTH);
    	glClearColor(0.0f,0.0f, 0.0f, 0.0f);            //set the background color to black when starts to glclear
    	glClearDepthf(1.0f);                               //set clear depth buffer bit to 1 when starts to glclear
    	glEnable(GL_DEPTH_TEST);
    	glDepthFunc(GL_LEQUAL);
    	glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
    }
    
    void MyRenderer::resize(int width, int height) {
    	LOGD("resize the renderer");
    	glViewport(0,0, width, height);  //window size
    	glMatrixMode(GL_PROJECTION);
    	glLoadIdentity();
    
    //	GLfloat ratio = (GLfloat)width/(GLfloat)height;
    	gluPerspective(45.0f, (GLfloat)width/(GLfloat)height, 0.1f, 100.0f);
    	//glOrthof(-2.0f, 2.0f, -2.0f, 2.0f, -2.0f, 2.0f);
    
    	glMatrixMode(GL_MODELVIEW);     // 选择模型观察矩阵
    	glLoadIdentity();                         // 重置模型观察矩阵
    }
    void MyRenderer::gluPerspective(GLfloat fovy, GLfloat aspect, GLfloat zNear, GLfloat zFar)
    {
        GLfloat top = zNear * ((GLfloat) tan(fovy * PI / 360.0));
        GLfloat bottom = -top;
        GLfloat left = bottom * aspect;
        GLfloat right = top * aspect;
        glFrustumf(left, right, bottom, top, zNear, zFar);
    }
    
    static GLfloat gColors[] = {
    	        1.0f,0.0f,0.0f, 1.0f,
    	        0.0f,1.0f,0.0f, 1.0f,
    	        0.0f,0.0f,1.0f, 1.0f,
    
    	        1.0f,0.0f,0.0f, 1.0f,
    	        0.0f,0.0f,1.0f, 1.0f,
    	        0.0f,1.0f,0.0f, 1.0f,
    
    	        1.0f,0.0f,0.0f, 1.0f,
    	        0.0f,1.0f,0.0f, 1.0f,
    	        0.0f,0.0f,1.0f, 1.0f,
    
    	        1.0f,0.0f,0.0f, 1.0f,
    	        0.0f,0.0f,1.0f, 1.0f,
    	        0.0f,1.0f,0.0f, 1.0f
    };

static GLfloat gVertices[]= {
    	        0.0f, 1.0f, 0.0f,
    	        -1.0f,-1.0f, 1.0f,
    	        1.0f,-1.0f, 1.0f,
    
    	        0.0f, 1.0f, 0.0f,
    	        1.0f,-1.0f, 1.0f,
    	        1.0f,-1.0f, -1.0f,
    
    	        0.0f, 1.0f, 0.0f,
    	        1.0f,-1.0f, -1.0f,
    	        -1.0f,-1.0f, -1.0f,
    
    	         0.0f, 1.0f, 0.0f,
    	        -1.0f,-1.0f,-1.0f,
    	        -1.0f,-1.0f, 1.0f
    };
    
    void MyRenderer::renderFrame() {
    	LOGD("renderFrame the renderer");
    
    
    	// starts to clear the color buffer and depth buffer with the value set in glclearcolor and glcleardepthf
    	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    	glLoadIdentity();                              // 重置模型观察矩阵
    	glTranslatef(0.0f,0.0f, -6.0f);             // 移入屏幕 6.0
    
    	glRotatef(rtri,0.0f,1.0f,0.0f);             // 绕Y轴旋转金字塔
    	glEnableClientState(GL_VERTEX_ARRAY);
    	glEnableClientState(GL_COLOR_ARRAY);
    	glColorPointer(4, GL_FLOAT, 0, gColors);
    
    	glVertexPointer(3, GL_FLOAT, 0, gVertices);
    	glDrawArrays(GL_TRIANGLES, 0, 12);
    	rtri += 0.2f;                       // 增加三角形的旋转变量
    	//LOGI("xxxxx");
    	glDisableClientState(GL_VERTEX_ARRAY);
    	glDisableClientState(GL_COLOR_ARRAY);
    	glFlush();              //force the OpenGL commands set above to execute
    
    	//force the OpenGL commands set above to execute. It will block the thread until above commands executed and returned.
    	//glFinish();
    }

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