利用JNI技术在Android中调用C++形式的OpenGL ES 2.0函数
1、 打开Eclipse，File-->New-->Project…-->Android-->AndroidApplication Project,Next-->Application Name:FillTriangle, PackageName:com.filltriangle.android,Minimum Required SDK:API 10Android2.3.3(Gingerbread),Next-->不勾选Create customlauncher icon，Next-->选中Blank Activity,Next-->Activity Name:FillTriangle,Finish-->Runas Android Application，查看是否一切运行正常；
2、 打开FillTriangleActivity.java，将其内容改为：
/* * Copyright (C) 2009 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */// OpenGL ES 2.0 code#include <jni.h>#include <android/log.h>#include <GLES2/gl2.h>#include <GLES2/gl2ext.h>#include <stdio.h>#include <stdlib.h>#include <math.h>#define LOG_TAG "libgl2jni"#define LOGI(...) __android_log_print(ANDROID_LOG_INFO,LOG_TAG,__VA_ARGS__)#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,__VA_ARGS__)static void printGLString(const char *name, GLenum s) { const char *v = (const char *) glGetString(s); LOGI("GL %s = %s\n", name, v);}static void checkGlError(const char* op) { for (GLint error = glGetError(); error; error = glGetError()) { LOGI("after %s() glError (0x%x)\n", op, error); }}static const char gVertexShader[] = "attribute vec4 vPosition;\n" "void main() {\n" " gl_Position = vPosition;\n" "}\n";static const char gFragmentShader[] = "precision mediump float;\n" "void main() {\n" " gl_FragColor = vec4(0.0, 1.0, 0.0, 1.0);\n" "}\n";GLuint loadShader(GLenum shaderType, const char* pSource) { GLuint shader = glCreateShader(shaderType); if (shader) { glShaderSource(shader, 1, &pSource, NULL); glCompileShader(shader); GLint compiled = 0; glGetShaderiv(shader, GL_COMPILE_STATUS, &compiled); if (!compiled) { GLint infoLen = 0; glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &infoLen); if (infoLen) { char* buf = (char*) malloc(infoLen); if (buf) { glGetShaderInfoLog(shader, infoLen, NULL, buf); LOGE("Could not compile shader %d:\n%s\n", shaderType, buf); free(buf); } glDeleteShader(shader); shader = 0; } } } return shader;}GLuint createProgram(const char* pVertexSource, const char* pFragmentSource) { GLuint vertexShader = loadShader(GL_VERTEX_SHADER, pVertexSource); if (!vertexShader) { return 0; } GLuint pixelShader = loadShader(GL_FRAGMENT_SHADER, pFragmentSource); if (!pixelShader) { return 0; } GLuint program = glCreateProgram(); if (program) { glAttachShader(program, vertexShader); checkGlError("glAttachShader"); glAttachShader(program, pixelShader); checkGlError("glAttachShader"); glLinkProgram(program); GLint linkStatus = GL_FALSE; glGetProgramiv(program, GL_LINK_STATUS, &linkStatus); if (linkStatus != GL_TRUE) { GLint bufLength = 0; glGetProgramiv(program, GL_INFO_LOG_LENGTH, &bufLength); if (bufLength) { char* buf = (char*) malloc(bufLength); if (buf) { glGetProgramInfoLog(program, bufLength, NULL, buf); LOGE("Could not link program:\n%s\n", buf); free(buf); } } glDeleteProgram(program); program = 0; } } return program;}GLuint gProgram;GLuint gvPositionHandle;bool setupGraphics(int w, int h) { printGLString("Version", GL_VERSION); printGLString("Vendor", GL_VENDOR); printGLString("Renderer", GL_RENDERER); printGLString("Extensions", GL_EXTENSIONS); LOGI("setupGraphics(%d, %d)", w, h); gProgram = createProgram(gVertexShader, gFragmentShader); if (!gProgram) { LOGE("Could not create program."); return false; } gvPositionHandle = glGetAttribLocation(gProgram, "vPosition"); checkGlError("glGetAttribLocation"); LOGI("glGetAttribLocation(\"vPosition\") = %d\n", gvPositionHandle); glViewport(0, 0, w, h); checkGlError("glViewport"); return true;}const GLfloat gTriangleVertices[] = { 0.0f, 0.5f, -0.5f, -0.5f, 0.5f, -0.5f };void renderFrame() { static float grey; grey += 0.01f; if (grey > 1.0f) { grey = 0.0f; } glClearColor(grey, grey, grey, 1.0f); checkGlError("glClearColor"); glClear( GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT); checkGlError("glClear"); glUseProgram(gProgram); checkGlError("glUseProgram"); glVertexAttribPointer(gvPositionHandle, 2, GL_FLOAT, GL_FALSE, 0, gTriangleVertices); checkGlError("glVertexAttribPointer"); glEnableVertexAttribArray(gvPositionHandle); checkGlError("glEnableVertexAttribArray"); glDrawArrays(GL_TRIANGLES, 0, 3); checkGlError("glDrawArrays");}extern "C" { JNIEXPORT void JNICALL Java_com_android_gl2jni_GL2JNILib_init(JNIEnv * env, jobject obj, jint width, jint height); JNIEXPORT void JNICALL Java_com_android_gl2jni_GL2JNILib_step(JNIEnv * env, jobject obj);};JNIEXPORT void JNICALL Java_com_android_gl2jni_GL2JNILib_init(JNIEnv * env, jobject obj, jint width, jint height){ setupGraphics(width, height);}JNIEXPORT void JNICALL Java_com_android_gl2jni_GL2JNILib_step(JNIEnv * env, jobject obj){ renderFrame();}12、利用NDK生成.so文件：选中工程，点击右键-->Properties-->Builders-->New,新建立一个Builder,在弹出的对话框上点中Program,点击OK；在弹出对话框EditConfiguration中，配置选项卡Main：Location中填入NDK安装目录，D:\ProgramFiles\Android\android-sdk\android-ndk-r9\ndk-build.cmd；WorkingDirectory中填入工程的根目录，E:\Test\Android\FillTriangle,点击Apply；配置选项卡Refresh,勾选Refreshresources upon completion, The entire workspace, Recursively includesub-folders,点击Apply;配置Build Options选项卡，勾选Allocate Console(necessary for input), After a “Clean”, Duringmanual builds, During auto builds, Specify working set of relevant resources,点击SpecifyResources..,勾选FillTriangle工程的jni目录，点击Finish,点击Apply，点击OK,会在\libs\armeabi目录下生成相应的libgl2jni.so库；
13、运行该工程，会显示绿色三角。
参考文献：
1、 以上代码来自adt-bundle-windows-x86_64-20130729中的例程；
2、 http://blog.csdn.net/fengbingchun/article/details/11580983