Opengl es2.0 学习笔记（一）初始化

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官网
http://khronos.org/bugzilla

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一、vs使用opengles2.0

1. 下载库区分x86 x64
2. C++ ->常规->包含目录->include文件夹
3. 链接器->附加依赖项:libEGL.lib,libGLESv2.lib
4. 链接器->常规->附加库目录
5. opengl es没有windows实现，angular提供了windows版 windows平台调用direct3D 需要copy这两个库扔到debug下 d3dcompiler_43.dll d3dcompiler_46.dll

二、初始化所用到的API

//创建display返回display
eglGetDisplay(EGLNativeDisplayType display_id);//初始化egl
eglInitialize//选择config
eglChooseConfig//根据conig获取format
eglGetConfigAttrib//创建surface
eglCreateWindowSurface
//创建上下文
eglCreateContext
//关联起来
eglMakeCurrent
//查询宽度高度
eglQuerySurface//使用rgba清空缓冲区的颜色
glClearColor(1,0,0,1);
//! 清空缓冲区
glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
//! 视口，在Windows窗口指定的位置和大小上绘制OpenGL内容
glViewport(0,0,_width,_height);
​				
//双缓冲，把缓冲区内容贴到屏幕上			
eglSwapBuffers(_display,_surface);
//销毁display
eglTerminate
//销毁上下文eglDestroyContext
//销毁surfaceeglDestroySurface

三、撸代码

#include "CELLWinApp.hpp"int APIENTRY _tWinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,LPTSTR    lpCmdLine,int       nCmdShow)
{UNREFERENCED_PARAMETER(hPrevInstance);UNREFERENCED_PARAMETER(hInstance);UNREFERENCED_PARAMETER(lpCmdLine);UNREFERENCED_PARAMETER(nCmdShow);CELL::CELLWinApp  app(hInstance);app.main(800,600);return 0;
}

#pragma once#include <Windows.h>
#include <tchar.h>#include <EGL/egl.h>
#include <gles2/gl2.h>namespace   CELL
{class   CELLWinApp{public://! 实例句柄HINSTANCE   _hInstance;//! 窗口句柄HWND        _hWnd;//! 窗口的高度int         _width;//! 窗口的宽度int         _height;/// for gles2.0EGLConfig   _config;EGLSurface  _surface;EGLContext  _context;EGLDisplay  _display;public:CELLWinApp(HINSTANCE hInstance):_hInstance(hInstance){WNDCLASSEX  winClass;winClass.lpszClassName  =   _T("CELLWinApp");winClass.cbSize         =   sizeof(winClass);winClass.style          =   CS_HREDRAW | CS_VREDRAW | CS_OWNDC;winClass.lpfnWndProc    =   wndProc;winClass.hInstance      =   hInstance;winClass.hIcon	        =   0;winClass.hIconSm	    =   0;winClass.hCursor        =   LoadCursor(hInstance, IDC_ARROW);winClass.hbrBackground  =   (HBRUSH)GetStockObject(BLACK_BRUSH);winClass.lpszMenuName   =   NULL;winClass.cbClsExtra     =   0;winClass.cbWndExtra     =   0;RegisterClassEx(&winClass);}virtual ~CELLWinApp(){UnregisterClass(_T("CELLWinApp"),_hInstance);}/***   初始化 OpenGLES2.0*/bool    initOpenGLES20(){const EGLint attribs[] ={//surrface   画在窗口上EGL_SURFACE_TYPE, EGL_WINDOW_BIT,EGL_BLUE_SIZE, 8,	//b 8位EGL_GREEN_SIZE, 8,	//g 8位EGL_RED_SIZE, 8,	//r 8位EGL_DEPTH_SIZE,24,//深度24位EGL_NONE//};EGLint 	format(0);EGLint	numConfigs(0);EGLint  major;EGLint  minor;//! 1_display	    =	eglGetDisplay(EGL_DEFAULT_DISPLAY);//! 2initeglInitialize(_display, &major, &minor);//! 3eglChooseConfig(_display, attribs, &_config, 1, &numConfigs);eglGetConfigAttrib(_display, _config, EGL_NATIVE_VISUAL_ID, &format);//! 4 _surface	    = 	eglCreateWindowSurface(_display, _config, _hWnd, NULL);//! 5EGLint attr[]   =   { EGL_CONTEXT_CLIENT_VERSION, 2, EGL_NONE, EGL_NONE };_context 	    = 	eglCreateContext(_display, _config, 0, attr);//! 6if (eglMakeCurrent(_display, _surface, _surface, _context) == EGL_FALSE){return false;}eglQuerySurface(_display, _surface, EGL_WIDTH,  &_width);eglQuerySurface(_display, _surface, EGL_HEIGHT, &_height);return  true;}/***   销毁OpenGLES2.0*/void    destroyOpenGLES20(){if (_display != EGL_NO_DISPLAY){eglMakeCurrent(_display, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);if (_context != EGL_NO_CONTEXT) {eglDestroyContext(_display, _context);}if (_surface != EGL_NO_SURFACE) {eglDestroySurface(_display, _surface);}eglTerminate(_display);}_display    =   EGL_NO_DISPLAY;_context    =   EGL_NO_CONTEXT;_surface    =   EGL_NO_SURFACE;}protected:static  LRESULT CALLBACK wndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam){CELLWinApp*  pThis   =   (CELLWinApp*)GetWindowLong(hWnd,GWL_USERDATA);if (pThis){return  pThis->onEvent(hWnd,msg,wParam,lParam);}if (WM_CREATE == msg){CREATESTRUCT*   pCreate =   (CREATESTRUCT*)lParam;SetWindowLong(hWnd,GWL_USERDATA,(DWORD_PTR)pCreate->lpCreateParams);}return  DefWindowProc( hWnd, msg, wParam, lParam );}public:/***   事件函数*/virtual LRESULT onEvent(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam){switch (msg){case WM_CLOSE:case WM_DESTROY:{::PostQuitMessage(0);}break;case WM_MOUSEMOVE:break;default:return  DefWindowProc( hWnd, msg, wParam, lParam ); }return  S_OK;}/***   绘制函数*/virtual void    render(){glClearColor(1,0,0,1);glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);glViewport(0,0,_width,_height);}/***   主函数*/int     main(int width,int height){//创建窗口句柄_hWnd   =   CreateWindowEx( NULL,_T("CELLWinApp"),_T("CELLWinApp"),WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,CW_USEDEFAULT,width,height, NULL, NULL,_hInstance, this);if (_hWnd == 0){return  -1;}//显示窗口ShowWindow(_hWnd,SW_SHOW);//初始化opengl es2.0if (!initOpenGLES20()){return  false;}MSG msg =   {0};while(msg.message != WM_QUIT){if (msg.message == WM_DESTROY || msg.message == WM_CLOSE){break;}/***   有消息，处理消息，无消息，则进行渲染绘制*/if( PeekMessage( &msg, NULL, 0, 0, PM_REMOVE ) ){ TranslateMessage( &msg );DispatchMessage( &msg );}else{render();eglSwapBuffers(_display,_surface);}}/***   销毁OpenGLES20*/destroyOpenGLES20();return  0;}};
}

四、创建错误

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–error LNK2019: 无法解析的外部符号 _main，该符号在函数___tmainCRTStartup 中被引用_

1.进入project->setting->c/c++,在category中选择preprocessor,在processor definitions中删除_CONSOLE,添加_WINDOWS
2.进入project->setting->Link, 在Projectoptions(子系统)中将 /subsystem:console改为/subsystem:windows.
3.保存设置，Rebuild All.

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–找不到 #include <EGL/egl.h> #include <gles2/gl2.h>文件

C+±>常规->包含目录->include文件夹存在问题，请检查

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–无法启动

debug下，没扔这两个库
d3dcompiler_43.dll
d3dcompiler_46.dll

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–找不到libEGL.lib
–找不到libGLESv2.lib

链接器->附加依赖项:libEGL.lib,libGLESv2.lib
链接器->常规->附加库目录 这两步存在问题

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