如下程序将一张图片显示到屏幕上。

首先是android jni程序公共头文件：

#include <jni.h>
#include <time.h>
#include <android/log.h>
#include <android/bitmap.h>

用宏来控制是否使用es1.x

//#define USING_ES11

分别包含两种情况下的头文件：

#ifdef USING_ES11
#include <GLES/gl.h>
#include <GLES/glext.h>
#else
#include <GLES2/gl2.h>
#include <GLES2/gl2ext.h>
#endif

接着添加一些公共头文件：

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

下面是一些通用函数， 主要是一些错误处理函数：

/***********************common function*************************/
#define  LOG_TAG    "libtexture_test.so"
#define  LOGI(...)  __android_log_print(ANDROID_LOG_INFO,LOG_TAG,__VA_ARGS__)
#define  LOGE(...)  __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,__VA_ARGS__)const static GLfloat PI = 3.1415f;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);}
}

然后是相关数据定义：

//data
const GLfloat gVertices[] = { -1, -1, 1, -1, -1, 1, 1, 1 };
const GLfloat gTexCoords[] = { 0, 1, 1, 1, 0, 0, 1, 0};

定义纹理ID：

GLuint textureID;

定义es2.0相关的Shader和函数：

#ifndef USING_ES11
static const char gVertexShader[] ="attribute vec4 a_Position;\n""attribute vec2 a_TexCoords; \n""varying vec2 v_TexCoords; \n""void main() {\n""  gl_Position = a_Position;\n"" v_TexCoords = a_TexCoords; \n""}\n";static const char gFragmentShader[] ="precision mediump float;\n""uniform sampler2D u_Texture; \n""varying vec2 v_TexCoords; \n""void main() {\n""  gl_FragColor = texture2D(u_Texture, v_TexCoords);\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 gPositionHandle;
GLuint gTexCoordsHandle;
GLuint gTexHandle;#endif

下面是我们的初始化函数：

首先第一部分是加载纹理数据：

static void init(JNIEnv * env, jobject bitmap)
{AndroidBitmapInfo  info;void*  pixels;int format;int ret;if ((ret = AndroidBitmap_getInfo(env, bitmap, &info)) < 0) {LOGE("AndroidBitmap_getInfo() failed ! error=%d", ret);return;}if (info.format == ANDROID_BITMAP_FORMAT_RGBA_8888) {LOGI("Bitmap format is  RGBA_8888 !");format = GL_RGBA;} else if (info.format == ANDROID_BITMAP_FORMAT_RGB_565) {LOGI("Bitmap format is  RGB_565 !");format = GL_RGB;}if ((ret = AndroidBitmap_lockPixels(env, bitmap, &pixels)) < 0) {LOGE("AndroidBitmap_lockPixels() failed ! error=%d", ret);}glGenTextures(1, &textureID);glBindTexture(GL_TEXTURE_2D, textureID);// Set filteringglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);glTexImage2D(GL_TEXTURE_2D, 0, format, info.width, info.height, 0, format, GL_UNSIGNED_BYTE, pixels);AndroidBitmap_unlockPixels(env, bitmap);

接着是es1.x相关的初始化：

#ifdef USING_ES11glShadeModel(GL_SMOOTH);                      // 启用阴影平滑glClearColor(0.0f, 0.0f, 0.0f, 0.0f);                  // 黑色背景glClearDepthf(1.0f);                         // 设置深度缓存glEnable(GL_DEPTH_TEST);                       // 启用深度测试glDepthFunc(GL_LEQUAL);                            // 所作深度测试的类型glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);          // 告诉系统对透视进行修正
#endif

接下来是es2.0相关始化：

#ifndef USING_ES11gProgram = createProgram(gVertexShader, gFragmentShader);if (!gProgram) {LOGE("Could not create program.");return ;}gPositionHandle = glGetAttribLocation(gProgram, "a_Position");checkGlError("glGetAttribLocation");LOGI("glGetAttribLocation(\"a_Position\") = %d\n",gPositionHandle);gTexCoordsHandle = glGetAttribLocation(gProgram, "a_TexCoords");checkGlError("glGetAttribLocation");LOGI("glGetAttribLocation(\"a_TexCoords\") = %d\n",gTexCoordsHandle);gTexHandle = glGetUniformLocation(gProgram, "u_Texture");checkGlError("glGetUniformLocation");LOGI("glGetUniformLocation(\"u_Texture\") = %d\n",gTexHandle);
#endif}

定义es1.x下的视角设置函数：

#ifdef USING_ES11
static void _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);
}
#endif

接下来定义视口大小：

static void resize(int w, int h)
{if (h==0)                                // 防止被零除{h=1;                          // 将Height设为1}glViewport(0, 0, w, h);                   // 重置当前的视口#if USING_ES11glMatrixMode(GL_PROJECTION);                        // 选择投影矩阵glLoadIdentity();                          // 重置投影矩阵GLfloat ratio = (GLfloat)w/(GLfloat)h;// 设置视口的大小_gluPerspective(45.0f,(GLfloat)w/(GLfloat)h,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
#endif}

接下来是绘制函数：

static void update()
{glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);#ifdef USING_ES11glLoadIdentity();glTranslatef(0, 0, -3.0f);glEnable(GL_TEXTURE_2D);glEnableClientState(GL_VERTEX_ARRAY);glEnableClientState(GL_TEXTURE_COORD_ARRAY);glVertexPointer(2, GL_FLOAT, 0, gVertices);glTexCoordPointer(2, GL_FLOAT, 0, gTexCoords);glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
#elseglUseProgram(gProgram);checkGlError("glUseProgram");glVertexAttribPointer(gPositionHandle, 2, GL_FLOAT, GL_FALSE, 0, gVertices);checkGlError("glVertexAttribPointer");glEnableVertexAttribArray(gPositionHandle);checkGlError("glEnableVertexAttribArray");glVertexAttribPointer(gTexCoordsHandle, 2, GL_FLOAT, GL_FALSE, 0, gTexCoords);checkGlError("glVertexAttribPointer");glEnableVertexAttribArray(gTexCoordsHandle);checkGlError("glEnableVertexAttribArray");glActiveTexture(GL_TEXTURE0);glUniform1i(gTexHandle, 0);glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);#endif
}