EGL和OpenGLESGLES顯示YUV視訊
1.EGL
EGL是OpenGL ES與系統原始視窗的適配層：
2.GLSL
頂點著色器針對每個頂點執行一次，用於確定頂點的位置。
片元著色器針對每個片元（畫素）執行一次，用於確定片元（畫素）的顏色。
3.Android向底層傳遞Surface控制程式碼
public class XPlay extends GLSurfaceView implements Runnable,SurfaceHolder.Callback
{
public XPlay(Context context, AttributeSet attrs) {
super( context, attrs );
}
@Override
public void run() {
Open("/sdcard/outyuv",getHolder().getSurface());
}
@Override
public void surfaceCreated(SurfaceHolder var1)
{
new Thread( this ).start();
}
@Override
public void surfaceChanged(SurfaceHolder var1, int var2, int var3, int var4)
{
}
@Override
public void surfaceDestroyed(SurfaceHolder var1)
{
}
public native void Open(String url,Object surface);
}
複製程式碼4.獲取原始視窗
#include <android/native_window_jni.h>
複製程式碼extern "C"
JNIEXPORT void JNICALL
Java_aplay_testopengles_XPlay_Open(JNIEnv *env, jobject instance, jstring url_, jobject surface) {
//1 獲取原始視窗
ANativeWindow *nwin = ANativeWindow_fromSurface(env,surface);
}
複製程式碼ANativeWindow_fromSurface()：返回與Java Surface物件關聯的ANativeWindow，通過原生程式碼與之互動。這獲得了返回的ANativeWindow的引用; 使用結束之後要使用ANativeWindow_release()，這樣它才不會洩漏。
ANativeWindow * ANativeWindow_fromSurface(
JNIEnv *env,
jobject surface
)
複製程式碼ANativeWindow：不透明型別，提供對本地視窗的訪問。
struct ANativeWindow
{
#ifdef __cplusplus
ANativeWindow()
: flags(0), minSwapInterval(0), maxSwapInterval(0), xdpi(0), ydpi(0)
{
common.magic = ANDROID_NATIVE_WINDOW_MAGIC;
common.version = sizeof(ANativeWindow);
memset(common.reserved, 0, sizeof(common.reserved));
}
/* Implement the methods that sp<ANativeWindow> expects so that it
can be used to automatically refcount ANativeWindow's. */
void incStrong(const void* id) const {
common.incRef(const_cast<android_native_base_t*>(&common));
}
void decStrong(const void* id) const {
common.decRef(const_cast<android_native_base_t*>(&common));
}
#endif
struct android_native_base_t common;
/* flags describing some attributes of this surface or its updater */
const uint32_t flags;
/* min swap interval supported by this updated */
const int minSwapInterval;
/* max swap interval supported by this updated */
const int maxSwapInterval;
/* horizontal and vertical resolution in DPI */
const float xdpi;
const float ydpi;
/* Some storage reserved for the OEM's driver. */
intptr_t oem[4];
/*
* Set the swap interval for this surface.
*
* Returns 0 on success or -errno on error.
*/
int (*setSwapInterval)(struct ANativeWindow* window,
int interval);
/*
* Hook called by EGL to acquire a buffer. After this call, the buffer
* is not locked, so its content cannot be modified. This call may block if
* no buffers are available.
*
* The window holds a reference to the buffer between dequeueBuffer and
* either queueBuffer or cancelBuffer, so clients only need their own
* reference if they might use the buffer after queueing or canceling it.
* Holding a reference to a buffer after queueing or canceling it is only
* allowed if a specific buffer count has been set.
*
* Returns 0 on success or -errno on error.
*/
int (*dequeueBuffer)(struct ANativeWindow* window,
struct ANativeWindowBuffer** buffer);
/*
* hook called by EGL to lock a buffer. This MUST be called before modifying
* the content of a buffer. The buffer must have been acquired with
* dequeueBuffer first.
*
* Returns 0 on success or -errno on error.
*/
int (*lockBuffer)(struct ANativeWindow* window,
struct ANativeWindowBuffer* buffer);
/*
* Hook called by EGL when modifications to the render buffer are done.
* This unlocks and post the buffer.
*
* The window holds a reference to the buffer between dequeueBuffer and
* either queueBuffer or cancelBuffer, so clients only need their own
* reference if they might use the buffer after queueing or canceling it.
* Holding a reference to a buffer after queueing or canceling it is only
* allowed if a specific buffer count has been set.
*
* Buffers MUST be queued in the same order than they were dequeued.
*
* Returns 0 on success or -errno on error.
*/
int (*queueBuffer)(struct ANativeWindow* window,
struct ANativeWindowBuffer* buffer);
/*
* hook used to retrieve information about the native window.
*
* Returns 0 on success or -errno on error.
*/
int (*query)(const struct ANativeWindow* window,
int what, int* value);
/*
* hook used to perform various operations on the surface.
* (*perform)() is a generic mechanism to add functionality to
* ANativeWindow while keeping backward binary compatibility.
*
* DO NOT CALL THIS HOOK DIRECTLY. Instead, use the helper functions
* defined below.
*
* (*perform)() returns -ENOENT if the 'what' parameter is not supported
* by the surface's implementation.
*
* The valid operations are:
* NATIVE_WINDOW_SET_USAGE
* NATIVE_WINDOW_CONNECT (deprecated)
* NATIVE_WINDOW_DISCONNECT (deprecated)
* NATIVE_WINDOW_SET_CROP (private)
* NATIVE_WINDOW_SET_BUFFER_COUNT
* NATIVE_WINDOW_SET_BUFFERS_GEOMETRY (deprecated)
* NATIVE_WINDOW_SET_BUFFERS_TRANSFORM
* NATIVE_WINDOW_SET_BUFFERS_TIMESTAMP
* NATIVE_WINDOW_SET_BUFFERS_DIMENSIONS
* NATIVE_WINDOW_SET_BUFFERS_FORMAT
* NATIVE_WINDOW_SET_SCALING_MODE (private)
* NATIVE_WINDOW_LOCK (private)
* NATIVE_WINDOW_UNLOCK_AND_POST (private)
* NATIVE_WINDOW_API_CONNECT (private)
* NATIVE_WINDOW_API_DISCONNECT (private)
* NATIVE_WINDOW_SET_BUFFERS_USER_DIMENSIONS (private)
* NATIVE_WINDOW_SET_POST_TRANSFORM_CROP (private)
*
*/
int (*perform)(struct ANativeWindow* window,
int operation, ... );
/*
* Hook used to cancel a buffer that has been dequeued.
* No synchronization is performed between dequeue() and cancel(), so
* either external synchronization is needed, or these functions must be
* called from the same thread.
*
* The window holds a reference to the buffer between dequeueBuffer and
* either queueBuffer or cancelBuffer, so clients only need their own
* reference if they might use the buffer after queueing or canceling it.
* Holding a reference to a buffer after queueing or canceling it is only
* allowed if a specific buffer count has been set.
*/
int (*cancelBuffer)(struct ANativeWindow* window,
struct ANativeWindowBuffer* buffer);
void* reserved_proc[2];
};
複製程式碼5.初始化EGL
#include <EGL/egl.h>
複製程式碼///EGL
//1 EGL display建立和初始化
EGLDisplay display = eglGetDisplay(EGL_DEFAULT_DISPLAY);
if(display == EGL_NO_DISPLAY)
{
LOGD("eglGetDisplay failed!");
return;
}
if(EGL_TRUE != eglInitialize(display,0,0))
{
LOGD("eglInitialize failed!");
return;
}
//2 surface
//2-1 surface視窗配置
//輸出配置
EGLConfig config;
EGLint configNum;
EGLint configSpec[] = {
EGL_RED_SIZE, 8,
EGL_GREEN_SIZE, 8,
EGL_BLUE_SIZE, 8,
EGL_SURFACE_TYPE,
EGL_WINDOW_BIT,
EGL_NONE // 屬性表以該常量為結束符
};
if(EGL_TRUE != eglChooseConfig(display,configSpec,&config,1,&configNum))
{
LOGD("eglChooseConfig failed!");
return;
}
//建立surface
EGLSurface winsurface = eglCreateWindowSurface(display,config,nwin,0);
if(winsurface == EGL_NO_SURFACE)
{
LOGD("eglCreateWindowSurface failed!");
return;
}
//3 context 建立關聯的上下文
const EGLint ctxAttr[] = {
EGL_CONTEXT_CLIENT_VERSION,2,EGL_NONE
};
EGLContext context = eglCreateContext(display,config,EGL_NO_CONTEXT,ctxAttr);
if(context == EGL_NO_CONTEXT)
{
LOGD("eglCreateContext failed!");
return;
}
if(EGL_TRUE != eglMakeCurrent(display,winsurface,winsurface,context))
{
LOGD("eglMakeCurrent failed!");
return;
}
LOGD("EGL Init Success!");
複製程式碼EGLDisplay eglGetDisplay(EGLNativeDisplayType display_id)：返回需要顯示內容的物件的控制程式碼。
EGLDisplay：EGL把這些不同平臺的顯示系統抽象為一個獨立的型別：EGLDisplay。
eglInitialize()：初始化EGLDisplay。
EGLBoolean eglInitialize(EGLDisplay display, EGLint* majorVersion, EGLint* minorVersion);
複製程式碼EGLConfig：初始化EGLDisplay過後，要選擇一個合適的“繪圖表面”。
EGLBoolean eglChooseConfig(EGLDisplay display,
const EGLint* attribs, // 你想要的屬性事先定義到這個陣列裡
EGLConfig* configs, // 圖形系統將返回若干滿足條件的配置到該陣列
EGLint maxConfigs, // 上面陣列的容量
EGLint* numConfigs); // 圖形系統返回的可用的配置個數
複製程式碼eglCreateWindowSurface()：為建立好的EGLDisplay建立視窗。
EGLSurface eglCreateWindowSurface(EGLDisplay display,
EGLConfig config,
EGLNativeWindowType window, // 在Windows上就是HWND型別
const EGLint* attribs); // 此屬性表非彼屬性表
複製程式碼EGLSurface：EGLSurface 可以是由 EGL 分配的離屏緩衝區（稱為“pbuffer”），或由作業系統分配的視窗。EGL 視窗 Surface 通過 eglCreateWindowSurface() 呼叫被建立。該呼叫將“視窗物件”作為引數，在 Android 上，該物件可以是 SurfaceView、SurfaceTexture、SurfaceHolder 或 Surface，所有這些物件下面都有一個 BufferQueue。當您進行此呼叫時，EGL 將建立一個新的 EGLSurface 物件，並將其連線到視窗物件的 BufferQueue 的生產方介面。此後，渲染到該 EGLSurface 會導致一個緩衝區離開佇列、進行渲染，然後排隊等待消耗方使用。
eglCreateContext()：eglCreateContext為當前渲染API（使用eglBindAPI設定）建立EGL渲染context，並返回context的控制程式碼。 context然後可以用於渲染到EGL繪圖表面。 如果eglCreateContext無法建立渲染context，則返回EGL_NO_CONTEXT。
EGLContext eglCreateContext(EGLDisplay display,
EGLConfig config,
EGLContext share_context,
EGLint const * attrib_list);
複製程式碼display：指定EGL顯示連線。
config：指定定義可用於渲染context的幀緩衝區資源的EGL幀緩衝區配置。
share_context：指定用於共享資料的另一個EGL渲染context，由與context相對應的客戶端API定義。 資料也與share_context共享資料的所有其他context共享。 EGL_NO_CONTEXT表示不會發生共享。
attrib_list：為正在建立的context指定屬性和屬性值。 只能指定屬性EGL_CONTEXT_CLIENT_VERSION。
EGLContext：OpenGL ES 圖形上下文，它代表了OpenGL狀態機；如果沒有它，OpenGL指令就沒有執行的環境。
eglMakeCurrent()：eglMakeCurrent將context繫結到當前渲染執行緒以及繪製和讀取表面。 繪製用於所有GL操作，除了讀取的任何畫素資料（glReadPixels，glCopyTexImage2D和glCopyTexSubImage2D），它取自讀取的幀緩衝區值。
如果呼叫執行緒已經有當前的渲染context，那麼該context將被重新整理並標記為不再是最新的。
當context首次生成時，viewport和scissor尺寸被設定為繪製表面的大小。 當context隨後變為當前時，viewport和scissor不會被修改。
EGLBoolean eglMakeCurrent( EGLDisplay display,
EGLSurface draw,
EGLSurface read,
EGLContext context);
複製程式碼6.頂點和片元shader初始化
#include <GLES2/gl2.h>
複製程式碼頂點著色器
片元著色器
//頂點和片元shader初始化
//頂點shader初始化
GLint vsh = InitShader(vertexShader,GL_VERTEX_SHADER);
//片元yuv420 shader初始化
GLint fsh = InitShader(fragYUV420P,GL_FRAGMENT_SHADER);
複製程式碼//頂點著色器glsl
#define GET_STR(x) #x
static const char *vertexShader = GET_STR(
attribute vec4 aPosition; //頂點座標
attribute vec2 aTexCoord; //材質頂點座標
varying vec2 vTexCoord; //輸出的材質座標
void main(){
vTexCoord = vec2(aTexCoord.x,1.0-aTexCoord.y);//以左上角為座標原點
gl_Position = aPosition;
}
);
//片元著色器,軟解碼和部分x86硬解碼
static const char *fragYUV420P = GET_STR(
precision mediump float; //精度
varying vec2 vTexCoord; //頂點著色器傳遞的座標
uniform sampler2D yTexture; //輸入的材質（不透明灰度，單畫素）
uniform sampler2D uTexture;
uniform sampler2D vTexture;
void main(){
vec3 yuv;//承載輸入的資訊
vec3 rgb;//承載輸出的資訊
yuv.r = texture2D(yTexture,vTexCoord).r;//獲取指定座標的材質顏色
yuv.g = texture2D(uTexture,vTexCoord).r - 0.5;
yuv.b = texture2D(vTexture,vTexCoord).r - 0.5;
rgb = mat3(1.0, 1.0, 1.0,
0.0,-0.39465,2.03211,
1.13983,-0.58060,0.0)*yuv;//指定的yuv轉換為rgb的公式
//輸出畫素顏色
gl_FragColor = vec4(rgb,1.0);
}
);
GLint InitShader(const char *code,GLint type)
{
//建立shader
GLint sh = glCreateShader(type);
if(sh == 0)
{
LOGD("glCreateShader %d failed!",type);
return 0;
}
//載入shader
glShaderSource(sh,
1, //shader數量
&code, //shader程式碼
0); //程式碼長度
//編譯shader
glCompileShader(sh);
//獲取編譯情況
GLint status;
glGetShaderiv(sh,GL_COMPILE_STATUS,&status);
if(status == 0)
{
LOGD("glCompileShader failed!");
return 0;
}
LOGD("glCompileShader success!");
return sh;
}
複製程式碼7.建立渲染程式
//建立渲染程式
GLint program = glCreateProgram();
if(program == 0)
{
LOGD("glCreateProgram failed!");
return;
}
//渲染程式中加入著色器程式碼
glAttachShader(program,vsh);
glAttachShader(program,fsh);
//連結程式
glLinkProgram(program);
GLint status = 0;
glGetProgramiv(program,GL_LINK_STATUS,&status);
if(status != GL_TRUE)
{
LOGD("glLinkProgram failed!");
return;
}
glUseProgram(program);
LOGD("glLinkProgram success!");
複製程式碼8.傳遞頂點資料
//加入三維頂點資料 兩個三角形組成正方形
static float vers[] = {
1.0f,-1.0f,0.0f,
-1.0f,-1.0f,0.0f,
1.0f,1.0f,0.0f,
-1.0f,1.0f,0.0f,
};
GLuint apos = (GLuint)glGetAttribLocation(program,"aPosition");
glEnableVertexAttribArray(apos);
//傳遞頂點
glVertexAttribPointer(apos,3,GL_FLOAT,GL_FALSE,12,vers);
複製程式碼9.傳遞材質資料
//加入材質座標資料
static float txts[] = {
1.0f,0.0f , //右下
0.0f,0.0f,
1.0f,1.0f,
0.0f,1.0f
};
GLuint atex = (GLuint)glGetAttribLocation(program,"aTexCoord");
glEnableVertexAttribArray(atex);
glVertexAttribPointer(atex,2,GL_FLOAT,GL_FALSE,8,txts);
複製程式碼10.材質紋理初始化
int width = 424;
int height = 240;
//材質紋理初始化
//設定紋理層
glUniform1i( glGetUniformLocation(program,"yTexture"),0); //對於紋理第1層
glUniform1i( glGetUniformLocation(program,"uTexture"),1); //對於紋理第2層
glUniform1i( glGetUniformLocation(program,"vTexture"),2); //對於紋理第3層
//建立opengl紋理
GLuint texts[3] = {0};
//建立三個紋理
glGenTextures(3,texts);
//設定紋理屬性
glBindTexture(GL_TEXTURE_2D,texts[0]);
//縮小的過濾器
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
//設定紋理的格式和大小
glTexImage2D(GL_TEXTURE_2D,
0, //細節基本 0預設
GL_LUMINANCE,//gpu內部格式 亮度，灰度圖
width,height, //拉昇到全屏
0, //邊框
GL_LUMINANCE,//資料的畫素格式 亮度，灰度圖 要與上面一致
GL_UNSIGNED_BYTE, //畫素的資料型別
NULL //紋理的資料
);
//設定紋理屬性
glBindTexture(GL_TEXTURE_2D,texts[1]);
//縮小的過濾器
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
//設定紋理的格式和大小
glTexImage2D(GL_TEXTURE_2D,
0, //細節基本 0預設
GL_LUMINANCE,//gpu內部格式 亮度，灰度圖
width/2,height/2, //拉昇到全屏
0, //邊框
GL_LUMINANCE,//資料的畫素格式 亮度，灰度圖 要與上面一致
GL_UNSIGNED_BYTE, //畫素的資料型別
NULL //紋理的資料
);
//設定紋理屬性
glBindTexture(GL_TEXTURE_2D,texts[2]);
//縮小的過濾器
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
//設定紋理的格式和大小
glTexImage2D(GL_TEXTURE_2D,
0, //細節基本 0預設
GL_LUMINANCE,//gpu內部格式 亮度，灰度圖
width/2,height/2, //拉昇到全屏
0, //邊框
GL_LUMINANCE,//資料的畫素格式 亮度，灰度圖 要與上面一致
GL_UNSIGNED_BYTE, //畫素的資料型別
NULL //紋理的資料
);
複製程式碼11.紋理顯示
////紋理的修改和顯示
FILE *fp = fopen(url,"rb");
if(!fp)
{
LOGD("open file %s failed!",url);
return;
}
unsigned char *buf[3] = {0};//將顯示的材質存放到buf中
buf[0] = new unsigned char[width*height];
buf[1] = new unsigned char[width*height/4];
buf[2] = new unsigned char[width*height/4];
for(int i = 0; i<10000;i++)
{
//420p yyyyyyyy uu vv
if(feof(fp) == 0)
{
//yyyyyyyy
fread(buf[0],1,width*height,fp);
fread(buf[1],1,width*height/4,fp);
fread(buf[2],1,width*height/4,fp);
}
//啟用第1層紋理,繫結到建立的opengl紋理
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D,texts[0]);
//替換紋理內容
glTexSubImage2D(GL_TEXTURE_2D,0,0,0,width,height,GL_LUMINANCE,GL_UNSIGNED_BYTE,buf[0]);
//啟用第2層紋理,繫結到建立的opengl紋理
glActiveTexture(GL_TEXTURE0+1);
glBindTexture(GL_TEXTURE_2D,texts[1]);
//替換紋理內容
glTexSubImage2D(GL_TEXTURE_2D,0,0,0,width/2,height/2,GL_LUMINANCE,GL_UNSIGNED_BYTE,buf[1]);
//啟用第2層紋理,繫結到建立的opengl紋理
glActiveTexture(GL_TEXTURE0+2);
glBindTexture(GL_TEXTURE_2D,texts[2]);
//替換紋理內容
glTexSubImage2D(GL_TEXTURE_2D,0,0,0,width/2,height/2,GL_LUMINANCE,GL_UNSIGNED_BYTE,buf[2]);
//三維繪製
glDrawArrays(GL_TRIANGLE_STRIP,0,4);
//視窗顯示
eglSwapBuffers(display,winsurface);
}
複製程式碼