绘制一个三角形的步骤：
创建 OpenGLES 环境（可以借助于 GLSurfaceView 创建的上下文对象）；
编译并链接着色器程序；
指定着色器程序，为着色器程序中的变量赋值；
绘制。
基于 GLSurfaceView 搭建 OpenGLES 环境
简单自定义 GLSurfaceView。
package com.byteflow.app;
import android.content.Context;
import android.opengl.GLSurfaceView;
import android.util.AttributeSet;
import android.util.Log;
import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;
public class MyGLSurfaceView extends GLSurfaceView {
private static final String TAG = "MyGLSurfaceView";
public static final int IMAGE_FORMAT_RGBA = 0x01;
public static final int IMAGE_FORMAT_NV21 = 0x02;
public static final int IMAGE_FORMAT_NV12 = 0x03;
public static final int IMAGE_FORMAT_I420 = 0x04;
private MyGLRender mGLRender;
private MyNativeRender mNativeRender;
public MyGLSurfaceView(Context context) {
this(context, null);
}
public MyGLSurfaceView(Context context, AttributeSet attrs) {
super(context, attrs);
this.setEGLContextClientVersion(3);
mNativeRender = new MyNativeRender();
mGLRender = new MyGLRender(mNativeRender);
setRenderer(mGLRender);
setRenderMode(RENDERMODE_CONTINUOUSLY);
}
public MyNativeRender getNativeRender() {
return mNativeRender;
}
public static class MyGLRender implements GLSurfaceView.Renderer {
private MyNativeRender mNativeRender;
MyGLRender(MyNativeRender myNativeRender) {
mNativeRender = myNativeRender;
}
@Override
public void onSurfaceCreated(GL10 gl, EGLConfig config) {
Log.d(TAG, "onSurfaceCreated() called with: gl = [" + gl + "], config = [" + config + "]");
mNativeRender.native_OnSurfaceCreated();
}
@Override
public void onSurfaceChanged(GL10 gl, int width, int height) {
Log.d(TAG, "onSurfaceChanged() called with: gl = [" + gl + "], width = [" + width + "], height = [" + height + "]");
mNativeRender.native_OnSurfaceChanged(width, height);
}
@Override
public void onDrawFrame(GL10 gl) {
Log.d(TAG, "onDrawFrame() called with: gl = [" + gl + "]");
mNativeRender.native_OnDrawFrame();
}
}
}
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JNI 类。
package com.byteflow.app;
public class MyNativeRender {
static {
System.loadLibrary("native-render");
}
public native void native_OnInit();
public native void native_OnUnInit();
public native void native_SetImageData(int format, int width, int height, byte[] bytes);
public native void native_OnSurfaceCreated();
public native void native_OnSurfaceChanged(int width, int height);
public native void native_OnDrawFrame();
}
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Native 层简单实现 JNI 。
//
// Created by ByteFlow on 2019/7/9.
//
#include "util/LogUtil.h"
#include <MyGLRenderContext.h>
#include "jni.h"
#define NATIVE_RENDER_CLASS_NAME "com/byteflow/app/MyNativeRender"
#ifdef __cplusplus
extern "C" {
#endif
/*
* Class: com_byteflow_app_MyNativeRender
* Method: native_OnInit
* Signature: ()V
*/
JNIEXPORT void JNICALL native_OnInit(JNIEnv *env, jobject instance)
{
MyGLRenderContext::GetInstance();
}
/*
* Class: com_byteflow_app_MyNativeRender
* Method: native_OnUnInit
* Signature: ()V
*/
JNIEXPORT void JNICALL native_OnUnInit(JNIEnv *env, jobject instance)
{
MyGLRenderContext::DestroyInstance();
}
/*
* Class: com_byteflow_app_MyNativeRender
* Method: native_SetImageData
* Signature: (III[B)V
*/
JNIEXPORT void JNICALL native_SetImageData
(JNIEnv *env, jobject instance, jint format, jint width, jint height, jbyteArray imageData)
{
int len = env->GetArrayLength (imageData);
uint8_t* buf = new uint8_t[len];
env->GetByteArrayRegion(imageData, 0, len, reinterpret_cast<jbyte*>(buf));
MyGLRenderContext::GetInstance()->SetImageData(format, width, height, buf);
delete[] buf;
env->DeleteLocalRef(imageData);
}
/*
* Class: com_byteflow_app_MyNativeRender
* Method: native_OnSurfaceCreated
* Signature: ()V
*/
JNIEXPORT void JNICALL native_OnSurfaceCreated(JNIEnv *env, jobject instance)
{
MyGLRenderContext::GetInstance()->OnSurfaceCreated();
}
/*
* Class: com_byteflow_app_MyNativeRender
* Method: native_OnSurfaceChanged
* Signature: (II)V
*/
JNIEXPORT void JNICALL native_OnSurfaceChanged
(JNIEnv *env, jobject instance, jint width, jint height)
{
MyGLRenderContext::GetInstance()->OnSurfaceChanged(width, height);
}
/*
* Class: com_byteflow_app_MyNativeRender
* Method: native_OnDrawFrame
* Signature: ()V
*/
JNIEXPORT void JNICALL native_OnDrawFrame(JNIEnv *env, jobject instance)
{
MyGLRenderContext::GetInstance()->OnDrawFrame();
}
#ifdef __cplusplus
}
#endif
static JNINativeMethod g_RenderMethods[] = {
{"native_OnInit", "()V", (void *)(native_OnInit)},
{"native_OnUnInit", "()V", (void *)(native_OnUnInit)},
{"native_SetImageData", "(III[B)V", (void *)(native_SetImageData)},
{"native_OnSurfaceCreated", "()V", (void *)(native_OnSurfaceCreated)},
{"native_OnSurfaceChanged", "(II)V", (void *)(native_OnSurfaceChanged)},
{"native_OnDrawFrame", "()V", (void *)(native_OnDrawFrame)},
};
static int RegisterNativeMethods(JNIEnv *env, const char *className, JNINativeMethod *methods, int methodNum)
{
LOGCATE("RegisterNativeMethods");
jclass clazz = env->FindClass(className);
if (clazz == NULL)
{
LOGCATE("RegisterNativeMethods fail. clazz == NULL");
return JNI_FALSE;
}
if (env->RegisterNatives(clazz, methods, methodNum) < 0)
{
LOGCATE("RegisterNativeMethods fail");
return JNI_FALSE;
}
return JNI_TRUE;
}
static void UnregisterNativeMethods(JNIEnv *env, const char *className)
{
LOGCATE("UnregisterNativeMethods");
jclass clazz = env->FindClass(className);
if (clazz == NULL)
{
LOGCATE("UnregisterNativeMethods fail. clazz == NULL");
return;
}
if (env != NULL)
{
env->UnregisterNatives(clazz);
}
}
// call this func when loading lib
extern "C" jint JNI_OnLoad(JavaVM *jvm, void *p)
{
LOGCATE("===== JNI_OnLoad =====");
jint jniRet = JNI_ERR;
JNIEnv *env = NULL;
if (jvm->GetEnv((void **) (&env), JNI_VERSION_1_6) != JNI_OK)
{
return jniRet;
}
jint regRet = RegisterNativeMethods(env, NATIVE_RENDER_CLASS_NAME, g_RenderMethods,
sizeof(g_RenderMethods) /
sizeof(g_RenderMethods[0]));
if (regRet != JNI_TRUE)
{
return JNI_ERR;
}
return JNI_VERSION_1_6;
}
extern "C" void JNI_OnUnload(JavaVM *jvm, void *p)
{
JNIEnv *env = NULL;
if (jvm->GetEnv((void **) (&env), JNI_VERSION_1_6) != JNI_OK)
{
return;
}
UnregisterNativeMethods(env, NATIVE_RENDER_CLASS_NAME);
}
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Native 层的 Render 封装类，其他的 Sample 都在此类中实现。
//
// Created by ByteFlow on 2019/7/9.
//
#include <TriangleSample.h>
#include "MyGLRenderContext.h"
#include "LogUtil.h"
MyGLRenderContext* MyGLRenderContext::m_pContext = nullptr;
MyGLRenderContext::MyGLRenderContext()
{
}
MyGLRenderContext::~MyGLRenderContext()
{
}
void MyGLRenderContext::SetImageData(int format, int width, int height, uint8_t *pData)
{
LOGCATE("MyGLRenderContext::SetImageData format=%d, width=%d, height=%d, pData=%p", format, width, height, pData);
NativeImage nativeImage;
nativeImage.format = format;
nativeImage.width = width;
nativeImage.height = height;
nativeImage.ppPlane[0] = pData;
switch (format)
{
case IMAGE_FORMAT_NV12:
case IMAGE_FORMAT_NV21:
nativeImage.ppPlane[1] = nativeImage.ppPlane[0] + width * height;
break;
case IMAGE_FORMAT_I420:
nativeImage.ppPlane[1] = nativeImage.ppPlane[0] + width * height;
nativeImage.ppPlane[2] = nativeImage.ppPlane[1] + width * height / 4;
break;
default:
break;
}
//m_TextureMapSample->LoadImage(&nativeImage);
}
void MyGLRenderContext::OnSurfaceCreated()
{
LOGCATE("MyGLRenderContext::OnSurfaceCreated");
glClearColor(1.0f,1.0f,0.5f, 1.0f);
m_Sample.Init();
}
void MyGLRenderContext::OnSurfaceChanged(int width, int height)
{
LOGCATE("MyGLRenderContext::OnSurfaceChanged [w, h] = [%d, %d]", width, height);
glViewport(0, 0, width, height);
}
void MyGLRenderContext::OnDrawFrame()
{
LOGCATE("MyGLRenderContext::OnDrawFrame");
glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
m_Sample.Draw();
}
MyGLRenderContext *MyGLRenderContext::GetInstance()
{
LOGCATE("MyGLRenderContext::GetInstance");
if (m_pContext == nullptr)
{
m_pContext = new MyGLRenderContext(http://www.amjmh.com/v/);
}
return m_pContext;
}
void MyGLRenderContext::DestroyInstance()
{
LOGCATE("MyGLRenderContext::DestroyInstance");
if (m_pContext)
{
delete m_pContext;
m_pContext = nullptr;
}
}