Android OpenGL ES NDK环境搭建

1.将GL线程执行函数调用转到c层代码。

import android.content.Context;
import android.opengl.GLSurfaceView;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;

class MyGLRenderer implements GLSurfaceView.Renderer
{
    public void onSurfaceCreated(GL10 gl, EGLConfig config)
    {
        NativeInterface.InitOpenGL();
    }

    public void onSurfaceChanged(GL10 gl, int width, int height)
    {
        NativeInterface.OnViewportChanged(width,height);
    }

    public void onDrawFrame(GL10 gl)
    {
        NativeInterface.RenderOneFrame();
    }
}

class MyGLSurface extends GLSurfaceView
{
    MyGLRenderer mRenderer;
    public MyGLSurface(Context context)
    {
        super(context);
        setEGLContextClientVersion(2);
        mRenderer=new MyGLRenderer();
        setRenderer(mRenderer);
    }
}

public class MainActivity extends AppCompatActivity {
    MyGLSurface mView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mView=new MyGLSurface(getApplication());
        setContentView(mView);
    }
}

2.创建jni接口。

public class NativeInterface {
    static {
        System.loadLibrary("mygles");
    }

    public static native void InitOpenGL();
    public static native void OnViewportChanged(float width,float height);
    public static native void RenderOneFrame();
}

3.jni层处理
Android.mk

LOCAL_PATH:=$(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE:=libmygles
LOCAL_SRC_FILES:=opengl.cpp


LOCAL_LDLIBS:=-llog -lGLESv2

include $(BUILD_SHARED_LIBRARY)

Application.mk

APP_ABI:=all
APP_STL:=gnustl_static
APP_CPPFLAGS:=-std=c++11 

opengl.cpp

#include
#include
#include
#include


extern "C" JNIEXPORT void Java_cn_battlefire_firstandroidapp_NativeInterface_InitOpenGL(JNIEnv*env,jobject obj)
{
    glClearColor(0.1f,0.4f,0.7f,1.0f);
}

extern "C" JNIEXPORT void Java_cn_battlefire_firstandroidapp_NativeInterface_OnViewportChanged(JNIEnv*env,jobject obj,jfloat width,jfloat height)
{
    glViewport(0,0,width,height);
}

extern "C" JNIEXPORT void Java_cn_battlefire_firstandroidapp_NativeInterface_RenderOneFrame(JNIEnv*env,jobject obj)
{
    glClear(GL_COLOR_BUFFER_BIT);
}

画三角形demo：
opengl.cpp

#include
#include
#include
#include
#include"Glm/glm.hpp"
#include"Glm/ext.hpp"

GLuint vbo;
GLuint simple_program;
GLint MLocation,VLocation,PLocation,positionLocation;

glm::mat4 identityMatrix;
glm::mat4 projectionMatrix;

#define info(...) __android_log_print(ANDROID_LOG_INFO,"BattleFire",__VA_ARGS__)

const char*vsCode="attribute vec3 position;\n"
"uniform mat4 M;\n"
"uniform mat4 V;\n"
"uniform mat4 P;\n"
"void main()\n"
"{\n"
"gl_Position=P*V*M*vec4(position,1.0);\n"
"}\n";

const char*fsCode="void main()\n"
"{\n"
"gl_FragColor=vec4(1.0,1.0,1.0,1.0);\n"
"}\n";

GLuint CompileShader(GLenum shaderType,const char*code)
{
    if(code==nullptr)
    {
        info("compile shader error,code is null");
        return 0;
    }
    GLuint shader=glCreateShader(shaderType);
    glShaderSource(shader,1,&code,nullptr);
    glCompileShader(shader);
    //check error
    GLint compileResult=0;
    glGetShaderiv(shader,GL_COMPILE_STATUS,&compileResult);
    if(compileResult==GL_FALSE)
    {
        info("compile shader error with code : %s",code);
        char szLogBuffer[1024]={0};
        GLsizei realLogLen=0;
        glGetShaderInfoLog(shader,1024,&realLogLen,szLogBuffer);
        info("error log : %s",szLogBuffer);
        glDeleteShader(shader);
        return 0;
    }
    return shader;
}

GLuint CreateProgram(const char*vsCode,const char*fsCode)
{
    GLuint program=glCreateProgram();
    GLuint vsShader=CompileShader(GL_VERTEX_SHADER,vsCode);
    if(vsShader==0)
    {
        info("compile vs shader fail");
        return 0;
    }
    GLuint  fsShader=CompileShader(GL_FRAGMENT_SHADER,fsCode);
    if(fsShader==0)
    {
        info("compile fs shader fail");
        return 0;
    }
    glAttachShader(program,vsShader);
    glAttachShader(program,fsShader);
    glLinkProgram(program);
    //check error 
    glDetachShader(program,vsShader);
    glDetachShader(program,fsShader);
    glDeleteShader(vsShader);
    glDeleteShader(fsShader);
    
    GLint linkResult=0;
    glGetProgramiv(program,GL_LINK_STATUS,&linkResult);
    if(linkResult==GL_FALSE)
    {
        info("link program error ");
        char szLogBuffer[1024];
        GLsizei realLogLen=0;
        glGetShaderInfoLog(program,1024,&realLogLen,szLogBuffer);
        info("error log : %s",szLogBuffer);
        glDeleteProgram(program);
        return 0;
    }
    return program;
}

extern "C" JNIEXPORT void Java_cn_battlefire_firstandroidapp_NativeInterface_InitOpenGL(JNIEnv*env,jobject obj)
{
    glClearColor(0.1f,0.4f,0.7f,1.0f);
    float vertices[]={
        -5.0f,-5.0f,-10.0f,
        5.0f,-5.0f,-10.0f,
        0.0f,5.0f,-10.0f
    };
    simple_program=CreateProgram(vsCode,fsCode);
    positionLocation=glGetAttribLocation(simple_program,"position");
    
    MLocation=glGetUniformLocation(simple_program,"M");
    VLocation=glGetUniformLocation(simple_program,"V");
    PLocation=glGetUniformLocation(simple_program,"P");
    
    glGenBuffers(1,&vbo);
    glBindBuffer(GL_ARRAY_BUFFER,vbo);
    glBufferData(GL_ARRAY_BUFFER,sizeof(float)*9,vertices,GL_STATIC_DRAW);
    glBindBuffer(GL_ARRAY_BUFFER,0);
}

extern "C" JNIEXPORT void Java_cn_battlefire_firstandroidapp_NativeInterface_OnViewportChanged(JNIEnv*env,jobject obj,jfloat width,jfloat height)
{
    glViewport(0,0,width,height);
    projectionMatrix=glm::perspective(50.0f,width/height,0.1f,1000.0f);
}

extern "C" JNIEXPORT void Java_cn_battlefire_firstandroidapp_NativeInterface_RenderOneFrame(JNIEnv*env,jobject obj)
{
    glClear(GL_COLOR_BUFFER_BIT);
    glUseProgram(simple_program);
    //update gpu program args
    glUniformMatrix4fv(MLocation,1,GL_FALSE,glm::value_ptr(identityMatrix));
    glUniformMatrix4fv(VLocation,1,GL_FALSE,glm::value_ptr(identityMatrix));
    glUniformMatrix4fv(PLocation,1,GL_FALSE,glm::value_ptr(projectionMatrix));
    
    glBindBuffer(GL_ARRAY_BUFFER,vbo);
    //set vertex data
    glEnableVertexAttribArray(positionLocation);
    glVertexAttribPointer(positionLocation,3,GL_FLOAT,GL_FALSE,sizeof(float)*3,0);
    
    glBindBuffer(GL_ARRAY_BUFFER,0);
    //draw
    glDrawArrays(GL_TRIANGLES,0,3);
    glUseProgram(0);
    glFlush();
}