1

我有一些时间，我读过关于 VBO 的文章，这就是我得到的：

http://img64.imageshack.us/img64/5733/fps8.jpg

好吧，比以前好多了。它是在发布时编译的。我使用 VBO（可能，如果一切正常的话）和 glDrawArrays 来绘制。

这是绘图代码。请给我建议如何优化它。我想要地形......呃几千 FPS，是真的吗？

void DrawVBO (void)
{
    int i;

    CVert*      m_pVertices; 
    CTexCoord*  m_pTexCoords;

    unsigned int    m_nTextureId;

    m_pVertices = NULL;
    m_pTexCoords = NULL;
    m_nVertexCount = 0;
    m_nVBOVertices = m_nVBOTexCoords = m_nTextureId = 0;


    if( IsExtensionSupported( "GL_ARB_vertex_buffer_object" ) )
    {
        // Pobierz wskaźniki na funkcje OpenGL 
        glGenBuffersARB = (PFNGLGENBUFFERSARBPROC) wglGetProcAddress("glGenBuffersARB");
        glBindBufferARB = (PFNGLBINDBUFFERARBPROC) wglGetProcAddress("glBindBufferARB");
        glBufferDataARB = (PFNGLBUFFERDATAARBPROC) wglGetProcAddress("glBufferDataARB");
        glDeleteBuffersARB = (PFNGLDELETEBUFFERSARBPROC) 
        wglGetProcAddress("glDeleteBuffersARB"); 
    }
    
    todrawquads=0;
    nIndex=0;


// my function counting how many quads I will draw


    for (i=0;i<MAX_CHUNKS_LOADED;i++)
    {
        if (chunks_loaded[i].created==1)
        {
            countquads(i);
        }
    }

    m_nVertexCount=4*todrawquads;

    m_pVertices = new CVec[m_nVertexCount];
    m_pTexCoords = new CTexCoord[m_nVertexCount];

// another my function adding every quad which i'm going to draw (its verticles) to array

    for (i=0;i<MAX_CHUNKS_LOADED;i++)
    {
        if (chunks_loaded[i].created==1)
        {
            addchunktodraw(i,m_pVertices,m_pTexCoords);
        }
    }

    
    glClearColor (1,1,1, 0.0);
    glColor3f(1,1,1);

    glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);        // Clear Screen And Depth Buffer
    glLoadIdentity ();                                          // Reset The Modelview Matrix
    
    fps++;

    // Camera settings.
    
    //gluLookAt (zom, zom, zom, 0.0, 0.0, 0.0, 0, 0, 1);

    gluLookAt (zoom, zoom, zoom, 0.0, 0.0, 0.0, 0, 0, 1);
    glRotatef((rot_x / 180 * 3.141592654f),1,0,0);  
    glRotatef((rot_y / 180 * 3.141592654f),0,1,0);
    glRotatef((rot_z / 180 * 3.141592654f),0,0,1);

    //m_nTextureId = t_terrain;

    // Generate And Bind The Vertex Buffer
    glGenBuffersARB( 1, &m_nVBOVertices );                          // Get A Valid Name
    glBindBufferARB( GL_ARRAY_BUFFER_ARB, m_nVBOVertices );         // Bind The Buffer
    // Load The Data
    glBufferDataARB( GL_ARRAY_BUFFER_ARB, m_nVertexCount*3*sizeof(float), m_pVertices, GL_STATIC_DRAW_ARB );

    // Generate And Bind The Texture Coordinate Buffer
    glGenBuffersARB( 1, &m_nVBOTexCoords );                         // Get A Valid Name
    glBindBufferARB( GL_ARRAY_BUFFER_ARB, m_nVBOTexCoords );        // Bind The Buffer
    // Load The Data
    glBufferDataARB( GL_ARRAY_BUFFER_ARB, m_nVertexCount*2*sizeof(float), m_pTexCoords, GL_STATIC_DRAW_ARB );

    // Enable Pointers
    glEnableClientState( GL_VERTEX_ARRAY );                     // Enable Vertex Arrays
    glEnableClientState( GL_TEXTURE_COORD_ARRAY );              // Enable Texture Coord Arrays

    glBindBufferARB( GL_ARRAY_BUFFER_ARB, m_nVBOVertices );
    glVertexPointer( 3, GL_FLOAT, 0, (char *) NULL );       // Set The Vertex Pointer To The Vertex Buffer
    glBindBufferARB( GL_ARRAY_BUFFER_ARB, m_nVBOTexCoords );
    glTexCoordPointer( 2, GL_FLOAT, 0, (char *) NULL );     // Set The TexCoord Pointer To The TexCoord Buffe

    glDrawArrays( GL_QUADS, 0, m_nVertexCount); // Draw All Of The Triangles At Once

    glDisableClientState( GL_VERTEX_ARRAY );                    // Disable Vertex Arrays
    glDisableClientState( GL_TEXTURE_COORD_ARRAY );             // Disable Texture Coord Arrays

    liniergb();

    glutSwapBuffers();

    delete [] m_pVertices; m_pVertices = NULL;
    delete [] m_pTexCoords; m_pTexCoords = NULL;
}

那么我能用它做什么呢？（上面的代码是主要的绘图功能）

编辑

我已经移动了这个：

if( IsExtensionSupported( "GL_ARB_vertex_buffer_object" ) )
{
    // Pobierz wskaźniki na funkcje OpenGL 
    glGenBuffersARB = (PFNGLGENBUFFERSARBPROC) wglGetProcAddress("glGenBuffersARB");
    glBindBufferARB = (PFNGLBINDBUFFERARBPROC) wglGetProcAddress("glBindBufferARB");
    glBufferDataARB = (PFNGLBUFFERDATAARBPROC) wglGetProcAddress("glBufferDataARB");
    glDeleteBuffersARB = (PFNGLDELETEBUFFERSARBPROC) 
    wglGetProcAddress("glDeleteBuffersARB"); 
}

到我的主要功能。应该没有改善吧。

编辑2

现在，我也可以看到它正在吃内存。每隔几秒钟，程序内存使用量就会越来越多……怎么了？我不删除什么？

编辑3

好的，非常感谢。我已经将一些代码移到绘图函数之外并且......更多的 fps ！非常感谢 ！

http://img197.imageshack.us/img197/5193/fpsfinal.jpg

它是 640x640 块（大 40 倍）的地图，带有 650'000 个四边形（大约是 70 倍以上），并且仍然约为 170 fps。伟大的 ！并且没有内存泄漏。再次感谢 ！

4

3 回答 3

8

您正在重新加载所有缓冲区并在每一帧中再次释放它们？停止这样做，您的帧速率将上升。

请注意，您当前的代码最终将用完 VBO 标识符，因为您永远不会删除您创建的 VBO。

链接扩展功能也绝对不需要每一帧都做。

于 2011-06-13T13:18:20.843 回答
1

您的 DrawVBO 函数应仅包含：

glClearColor (1,1,1, 0.0);
glColor3f(1,1,1);

glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);        // Clear Screen And Depth Buffer
glLoadIdentity ();                                          // Reset The Modelview Matrix

fps++;

// Camera settings.

//gluLookAt (zom, zom, zom, 0.0, 0.0, 0.0, 0, 0, 1);

gluLookAt (zoom, zoom, zoom, 0.0, 0.0, 0.0, 0, 0, 1);
glRotatef((rot_x / 180 * 3.141592654f),1,0,0);  
glRotatef((rot_y / 180 * 3.141592654f),0,1,0);
glRotatef((rot_z / 180 * 3.141592654f),0,0,1);

// Enable Pointers
glEnableClientState( GL_VERTEX_ARRAY );                     // Enable Vertex Arrays
glEnableClientState( GL_TEXTURE_COORD_ARRAY );              // Enable Texture Coord Arrays

glBindBufferARB( GL_ARRAY_BUFFER_ARB, m_nVBOVertices );
glVertexPointer( 3, GL_FLOAT, 0, (char *) NULL );       // Set The Vertex Pointer To The Vertex Buffer
glBindBufferARB( GL_ARRAY_BUFFER_ARB, m_nVBOTexCoords );
glTexCoordPointer( 2, GL_FLOAT, 0, (char *) NULL );     // Set The TexCoord Pointer To The TexCoord Buffe

glDrawArrays( GL_QUADS, 0, m_nVertexCount); // Draw All Of The Triangles At Once

glDisableClientState( GL_VERTEX_ARRAY );                    // Disable Vertex Arrays
glDisableClientState( GL_TEXTURE_COORD_ARRAY );             // Disable Texture Coord Arrays

liniergb();

glutSwapBuffers();

您需要将其余部分移动到仅在启动时（或地形变化时）调用一次的单独函数。

于 2011-06-13T14:18:18.270 回答
1

有几件事很突出：

在您的绘图功能中，您正在为几何数据分配内存

    m_pVertices = new CVec[m_nVertexCount];
    m_pTexCoords = new CTexCoord[m_nVertexCount];

内存分配是一项极其昂贵的操作，这是应该只做一次的事情之一。OpenGL 并不意味着要“初始化”——但你要传递给它的数据结构是！

在这里，您将新分配的缓冲区复制到 OpenGL，每帧一次又一次。这与该做什么完全相反。

// Generate And Bind The Vertex Buffer
glGenBuffersARB( 1, &m_nVBOVertices );                          // Get A Valid Name
glBindBufferARB( GL_ARRAY_BUFFER_ARB, m_nVBOVertices );         // Bind The Buffer
// Load The Data
glBufferDataARB( GL_ARRAY_BUFFER_ARB, m_nVertexCount*3*sizeof(float), m_pVertices, GL_STATIC_DRAW_ARB );

// Generate And Bind The Texture Coordinate Buffer
glGenBuffersARB( 1, &m_nVBOTexCoords );                         // Get A Valid Name
glBindBufferARB( GL_ARRAY_BUFFER_ARB, m_nVBOTexCoords );        // Bind The Buffer
// Load The Data
glBufferDataARB( GL_ARRAY_BUFFER_ARB, m_nVertexCount*2*sizeof(float), m_pTexCoords, GL_STATIC_DRAW_ARB );

VBO 的整个想法是，只加载一次数据，将其复制到 OpenGL，然后不再重新分配。请注意，这不是 OpenGL 初始化，而是数据初始化，这是完全合理的。我看到你已经命名了你的变量m_pVertices并m_pTexCoords表明这些是类成员变量。那么解决方案很简单：将整个初始化代码移动到某个加载器函数中。另外，我强烈建议不要使用裸 C++ 数组，而是使用std::vector.

所以让我们解决这个问题：

// Load Extensions only once. Well, once per context actually, however
// why don't you just use an extension wrapper and forget about those
// gritty details? Google GLEW or GLee
void init_extensions()
{
    if( IsExtensionSupported( "GL_ARB_vertex_buffer_object" ) )
    {
    // Pobierz wska\u017aniki na funkcje OpenGL 
    glGenBuffersARB = (PFNGLGENBUFFERSARBPROC) wglGetProcAddress("glGenBuffersARB");
    glBindBufferARB = (PFNGLBINDBUFFERARBPROC) wglGetProcAddress("glBindBufferARB");
    glBufferDataARB = (PFNGLBUFFERDATAARBPROC) wglGetProcAddress("glBufferDataARB");
    glDeleteBuffersARB = (PFNGLDELETEBUFFERSARBPROC) wglGetProcAddress("glDeleteBuffersARB"); 
    }
}

class Block0r
{
protected:
    GLuint m_nTextureId;
    GLuint m_nVBOVertices;
    GLuint m_nVBOTexCoords;
    GLuint m_nVertexCount;

    // Call this one time to load the data    
    void LoadVBO()
    {
        std::vector<CVert> vertices;
        std::vector<CTexCoord> texCoords;
        // my function counting how many quads I will draw

        todrawquads = 0;

        for(int i=0; i < MAX_CHUNKS_LOADED; i++) {
            if( chunks_loaded[i].created == 1 ) {
                countquads(i);
            }
        }

        m_nVertexCount = 4*todrawquads;

        vertices.resize(vertexcount);
        texcoords.resize(vertexcount);


        for (i=0;i<MAX_CHUNKS_LOADED;i++) {
            if (chunks_loaded[i].created==1) {
                addchunktodraw(i, &vertices[0], &texcoords[0]);
            }
        }

        glGenBuffersARB( 1, &m_nVBOVertices );
            glBindBufferARB( GL_ARRAY_BUFFER_ARB, m_nVBOVertices );
            glBufferDataARB( GL_ARRAY_BUFFER_ARB, vertices.size()*sizeof(CVert), &vertices[0], GL_STATIC_DRAW_ARB );

        glGenBuffersARB( 1, &m_nVBOTexCoords );
            glBindBufferARB( GL_ARRAY_BUFFER_ARB, m_nVBOTexCoords );
        glBufferDataARB( GL_ARRAY_BUFFER_ARB, texCoords.size()*sizeof(CTexCoord), &texCoords[0], GL_STATIC_DRAW_ARB );
    }

    void DrawVBO()
    {
        glClearColor (1,1,1, 0.0);
        glColor3f(1,1,1);

        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        glMatrixMode(GL_PROJECTION);
            setup_projection(); // this should really be done in the drawing handler

        glMatrixMode(GL_MODELVIEW); // don't asssume a certain matrix being active!
        glLoadIdentity();

        fps++;

        gluLookAt (zoom, zoom, zoom, 0.0, 0.0, 0.0, 0, 0, 1);
        glRotatef((rot_x / 180 * 3.141592654f),1,0,0);  
        glRotatef((rot_y / 180 * 3.141592654f),0,1,0);
        glRotatef((rot_z / 180 * 3.141592654f),0,0,1);

        glEnableClientState( GL_VERTEX_ARRAY );
        glEnableClientState( GL_TEXTURE_COORD_ARRAY );

        glBindBufferARB( GL_ARRAY_BUFFER_ARB, m_nVBOVertices );
        glVertexPointer( 3, GL_FLOAT, 0, (GLvoid *) 0 );

        glBindBufferARB( GL_ARRAY_BUFFER_ARB, m_nVBOTexCoords );
        glTexCoordPointer( 2, GL_FLOAT, 0, (GLvoid *) 0 );

        glDrawArrays( GL_QUADS, 0, m_nVertexCount);
        glDisableClientState( GL_VERTEX_ARRAY );
        glDisableClientState( GL_TEXTURE_COORD_ARRAY );
        liniergb();

        glutSwapBuffers();
    }
}

附带说明：喜欢// Generate And Bind The Vertex Buffer或 // Set The Vertex Pointer To The Vertex Buffer不是很有用的评论。这些注释只是多余地说明，无论如何人们可以从代码中读取什么。注释应该添加到代码中，其内部工作方式不是立即可以理解的，或者如果您必须进行某种破解来修复某些东西，而这种破解会在几个月内让其他人或您自己感到困惑。

于 2011-06-13T14:32:31.220 回答