OpenGL7-2-快速绘制

    添加时间:2013-7-16 点击量:


    #include CELLWinApp.hpp
    #include <gl/GLU.h>
    #include <assert.h>
    #include <math.h>
    #pragma comment(lib,opengl32.lib)
    #pragma comment(lib,glu32.lib)
    #pragma comment(lib,winmm.lib)



    /
    这个例子介绍如何应用
    glEnableClientState,
    glVertexPointer.
    glColorPointer,
    glTexCoordPointer,
    glDrawArrays
    函数进行绘制



    接上一个例子,上一个例子中应用了三个缓冲区,定点缓冲区,纹理缓冲区,色彩缓冲
    缓冲区多了今后灵活度增长了,然则经管却很麻烦。
    OpenGL也支撑一个零丁的缓冲区



    /



    struct Vertex
    {
    float x, y, z;
    float u,v;
    float r, g, b;
    };


    Vertex g_cubeVertices[] =
    {
    { -1.0f,-1.0f, 1.0f,0.0f, 0.0f,1.0f, 0.0f, 0.0f },
    { 1.0f,-1.0f, 1.0f,1.0f, 0.0f,1.0f, 0.0f, 0.0f },
    { 1.0f, 1.0f, 1.0f,1.0f, 1.0f,1.0f, 0.0f, 0.0f },
    { -1.0f, 1.0f, 1.0f,0.0f, 1.0f,1.0f, 0.0f, 0.0f },


    { -1.0f,-1.0f,-1.0f,1.0f, 0.0f,0.0f, 1.0f, 0.0f },
    { -1.0f, 1.0f,-1.0f,1.0f, 1.0f,0.0f, 1.0f, 0.0f },
    { 1.0f, 1.0f,-1.0f,0.0f, 1.0f,0.0f, 1.0f, 0.0f },
    { 1.0f,-1.0f,-1.0f,0.0f, 0.0f,0.0f, 1.0f, 0.0f },


    { -1.0f, 1.0f,-1.0f,0.0f, 1.0f,0.0f, 0.0f, 1.0f },
    { -1.0f, 1.0f, 1.0f,0.0f, 0.0f,0.0f, 0.0f, 1.0f },
    { 1.0f, 1.0f, 1.0f,1.0f, 0.0f,0.0f, 0.0f, 1.0f },
    { 1.0f, 1.0f,-1.0f,1.0f, 1.0f,0.0f, 0.0f, 1.0f },


    { -1.0f,-1.0f,-1.0f,1.0f, 1.0f,1.0f, 1.0f, 0.0f },
    { 1.0f,-1.0f,-1.0f,0.0f, 1.0f,1.0f, 1.0f, 0.0f },
    { 1.0f,-1.0f, 1.0f,0.0f, 0.0f,1.0f, 1.0f, 0.0f },
    { -1.0f,-1.0f, 1.0f,1.0f, 0.0f,1.0f, 1.0f, 0.0f },


    { 1.0f,-1.0f,-1.0f,1.0f, 0.0f,1.0f, 0.0f, 1.0f },
    { 1.0f, 1.0f,-1.0f,1.0f, 1.0f,1.0f, 0.0f, 1.0f },
    { 1.0f, 1.0f, 1.0f,0.0f, 1.0f,1.0f, 0.0f, 1.0f },
    { 1.0f,-1.0f, 1.0f,0.0f, 0.0f,1.0f, 0.0f, 1.0f },


    { -1.0f,-1.0f,-1.0f,0.0f, 0.0f,0.0f, 1.0f, 1.0f },
    { -1.0f,-1.0f, 1.0f,1.0f, 0.0f,0.0f, 1.0f, 1.0f },
    { -1.0f, 1.0f, 1.0f,1.0f, 1.0f,0.0f, 1.0f, 1.0f },
    { -1.0f, 1.0f,-1.0f,0.0f, 1.0f,0.0f, 1.0f, 1.0f }
    };



    class Tutorial7 :public CELL::Graphy::CELLWinApp
    {
    public:
    Tutorial7(HINSTANCE hInstance)
    :CELL::Graphy::CELLWinApp(hInstance)
    {
    _lbtnDownFlag = false;
    _fSpinY = 0;
    _fSpinX = 0;
    }
    virtual void render()
    {
    do
    {
    glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);



    glMatrixMode( GL_MODELVIEW );
    glLoadIdentity();
    glTranslatef( 0.0f, 0.0f, -5.0f );


    glRotatef( -_fSpinY, 1.0f, 0.0f, 0.0f );
    glRotatef( -_fSpinX, 0.0f, 1.0f, 0.0f );


    glEnableClientState( GL_VERTEX_ARRAY );
    glEnableClientState( GL_COLOR_ARRAY );
    glEnableClientState( GL_TEXTURE_COORD_ARRAY );



    /
    这里大师可以慢慢领会
    /
    float addrVertex = (float)g_cubeVertices;
    float uvAddress = (float)&g_cubeVertices[0].u;


    float colorAddress = (float)&g_cubeVertices[0].r;


    //--------------元素个数---元素类型---元素之间的内存偏移---数据地址
    //OpenGL按照元素之间的内存偏移来策画下一个元素的地位。
    glVertexPointer( 3, GL_FLOAT, sizeof(Vertex), addrVertex );
    glColorPointer( 3, GL_FLOAT, sizeof(Vertex), colorAddress);
    glTexCoordPointer( 2, GL_FLOAT, sizeof(Vertex), uvAddress );


    glDrawArrays( GL_QUADS, 0, 24 );


    glDisableClientState( GL_VERTEX_ARRAY );
    glDisableClientState( GL_COLOR_ARRAY );
    glDisableClientState( GL_TEXTURE_COORD_ARRAY );



    SwapBuffers( _hDC );
    } while (false);
    }


    /
    生成投影矩阵
    后面为了重用性,我们会写一个专门的matrix类,完成矩阵的一系列擦做
    这个是很有必必要的,当你对Opengl懂得的络续深切,你会发明,很多都是和数学有关的
    /
    void perspective(float fovy,float aspect,float zNear,float zFar,float matrix[4][4])
    {
    assert(aspect != float(0));
    assert(zFar != zNear);
    #define PI 3.14159265358979323f


    float rad = fovy (PI / 180);


    float halfFovy = tan(rad / float(2));
    matrix[0][0] = float(1) / (aspect halfFovy);
    matrix[1][1] = float(1) / (halfFovy);
    matrix[2][2] = -(zFar + zNear) / (zFar - zNear);
    matrix[2][3] = -float(1);
    matrix[3][2] = -(float(2) zFar zNear) / (zFar - zNear);
    #undef PI
    }
    virtual void onInit()
    {
    /
    调用父类的函数。
    /
    CELL::Graphy::CELLWinApp::onInit();

    glMatrixMode( GL_PROJECTION );


    GLfloat matrix[4][4] =
    {
    0,0,0,0,
    0,0,0,0,
    0,0,0,0,
    0,0,0,0
    };
    perspective(45.0f, (GLfloat)_winWidth / (GLfloat)_winHeight, 0.1f, 100.0f,matrix);
    glLoadMatrixf((float)matrix);


    glClearColor(0,0,0,1);


    /
    增长如下两句话
    glEnable(GL_DEPTH_TEST); 启动深度测试,如许,有遮挡策画,被隐瞒的将覆盖
    glEnable(GL_TEXTURE_2D); 启动纹理,支撑纹理贴图,如许才可以绘制纹理出来
    /
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_TEXTURE_2D);
    /
    读一个bmp
    /
    HBITMAP hBmp = (HBITMAP)LoadImageA(0,1.bmp,IMAGE_BITMAP,0,0,LR_LOADFROMFILE);
    /
    获取的大小
    /
    BITMAP bmpInf = {0};
    GetObject(hBmp,sizeof(bmpInf),&bmpInf);
    /
    获取的色彩数据(r,g,b)
    /
    int size = bmpInf.bmHeight bmpInf.bmWidth 3;
    char data = new char[size];


    BITMAPINFO bi;
    bi.bmiHeader.biSize = sizeof(bi.bmiHeader);
    bi.bmiHeader.biWidth = bmpInf.bmWidth;
    bi.bmiHeader.biHeight = bmpInf.bmHeight;
    bi.bmiHeader.biPlanes = 1;
    bi.bmiHeader.biBitCount = 24;
    bi.bmiHeader.biCompression = BI_RGB;
    bi.bmiHeader.biSizeImage = size;
    bi.bmiHeader.biClrUsed = 0;
    bi.bmiHeader.biClrImportant = 0;



    /
    获取rgb数据
    /
    int idata = GetDIBits(_hDC,hBmp,0,bi.bmiHeader.biHeight,data,&bi,DIB_RGB_COLORS);


    /
    产生一个纹理Id,可以认为是纹理句柄,后面的操纵将书用这个纹理id
    /
    glGenTextures( 1, &_textureId );


    /
    应用这个纹理id,或者叫绑定(接洽关系)
    /
    glBindTexture( GL_TEXTURE_2D, _textureId );
    /
    指定纹理的放大,缩小滤波,应用线性体式格式,即当放大的时辰插值体式格式
    /
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);

    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
    /
    将的rgb数据上传给opengl.
    /
    glTexImage2D(
    GL_TEXTURE_2D, //! 指定是二维
    0, //! 指定为第一级别,纹理可以做mipmap,即lod,离近的就采取级别大的,远则应用较小的纹理
    GL_RGB, //! 纹理的应用的存储格局
    bmpInf.bmWidth, //! 宽度,老一点的显卡,不支撑不规矩的纹理,即宽度和高度不是2^n。
    bmpInf.bmHeight, //! 宽度,老一点的显卡,不支撑不规矩的纹理,即宽度和高度不是2^n。
    0, //! 是否的边
    GL_BGR_EXT, //! 数据的格局,bmp中,windows,操纵体系中存储的数据是bgr格局
    GL_UNSIGNED_BYTE, //! 数据是8bit数据
    data
    );
    []data;
    /
    删除
    /
    DeleteObject(hBmp);

    }


    virtual int events(unsigned msg, unsigned wParam, unsigned lParam)
    {
    switch(msg)
    {
    case WM_LBUTTONDOWN:
    {
    _mousePos.x = LOWORD (lParam);
    _mousePos.y = HIWORD (lParam);
    _lbtnDownFlag = true;
    SetCapture(_hWnd);
    }
    break;
    case WM_LBUTTONUP:
    {
    _lbtnDownFlag = false;
    ReleaseCapture();
    }
    break;
    case WM_MOUSEMOVE:
    {
    int curX = LOWORD (lParam);
    int curY = HIWORD (lParam);


    if( _lbtnDownFlag )
    {
    _fSpinX -= (curX - _mousePos.x);
    _fSpinY -= (curY - _mousePos.y);
    }


    _mousePos.x = curX;
    _mousePos.y = curY;
    }
    break;
    }
    return __super::events(msg,wParam,lParam);
    }
    protected:
    unsigned _primitiveType;
    /
    保存纹理Id
    /
    unsigned _textureId;


    float _fSpinX ;
    float _fSpinY;
    POINT _mousePos;
    bool _lbtnDownFlag;
    };


    int CALLBACK _tWinMain(
    HINSTANCE hInstance,
    HINSTANCE hPrevInstance,
    LPTSTR lpCmdLine,
    int nShowCmd

    {
    (void)hInstance;
    (void)hPrevInstance;
    (void)lpCmdLine;
    (void)nShowCmd;


    Tutorial7 winApp(hInstance);
    winApp.start(640,480);
    return 0;
    }

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