Vertex Arabellek Nesnesi (VBO) ile Kinect Point Cloud Oluşturma

Question

Dinamik nokta bulutu görselleştiricisi oluşturmaya çalışıyorum. Noktalar Kinect Sensor ile her çerçevede güncellenir. Ekranları açmak için OpenCV ve GLUT kullanarak ekrana geliyorum. OpenCV API'si, xyz konumu için 640 x 480 (float *) ve rgb renk verisi için 640 x 480 (int *) döndürür. En yüksek performansı elde etmek için, Vertex Buffer Nesnesini basit bir Vertex Array yerine akış modunda kullanıyorum. Vertex Dizisi ile işleyebiliyorum, ancak VBO uygulamamla hiçbir şey yapılmıyor. Deklarasyonlarda bir sürü farklı sipariş denedim, ama neyi kaçırdığımı bulamıyorum. Birisi beni doğru yöne yönlendirmeye çalışabilir mi? (Christian Rau tarafından sorulan olarak hep şeffaf yanlış sürümü rewrited, böylece siz benim hataları anlayabileceği)

int main() 
{ 
    //Delaring variables, inittiating glut, setting camera and checking the compatibility as http://www.songho.ca/opengl/gl_vbo.html 
    glutDisplayFunc(displayCB); 
    glutIdleFunc(displayCB); 
    ... 
    //Inittiating the vertex buffers 
    if(vboSupported) 
    { 
     glGenBuffers(1, &vertex_buffer); 
     glBindBuffer(GL_ARRAY_BUFFER_ARB, buffer); 
     glBufferData(GL_ARRAY_BUFFER_ARB, (sizeof(GLfloat) * 640 * 480 * 3), 0, GL_STREAM_DRAW_ARB); 
     glBufferSubData(GL_ARRAY_BUFFER_ARB, 0, (sizeof(float) * 640 * 480 * 3), point_cloud.points_position); 

     glGenBuffers(2, &color_buffer); 
     glBindBuffer(GL_ARRAY_BUFFER_ARB, buffer); 
     glBufferData(GL_ARRAY_BUFFER_ARB, (sizeof(GLbyte) * 640 * 480 * 3), 0, GL_STREAM_DRAW_ARB); 
     glBufferSubData(GL_ARRAY_BUFFER_ARB, 0, (sizeof(char) * 640 * 480 * 3), point_cloud.points_color); 
    } 
    //glutMainLoop(), cleaning memory, ending main 
    .. 
} 

//Updating the screen 
void displayCB() 
{ 
    point_cloud.update(); 

    // clear buffer 
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT); 

    // save the initial ModelView matrix before modifying ModelView matrix 
    glPushMatrix(); 

     glBindBuffer(GL_ARRAY_BUFFER_ARB, color_buffer); 
     glBufferSubData(GL_ARRAY_BUFFER_ARB, 0, (sizeof(char) * 640 * 480 * 3), point_cloud.points_color); 
     glColorPointer(3, GL_UNSIGNED_BYTE, 0, 0); 

     glBindBuffer(GL_ARRAY_BUFFER_ARB, vertex_buffer); 
     glBufferSubData(GL_ARRAY_BUFFER_ARB, 0, (sizeof(float) * 640 * 480 * 3), point_cloud.points_position); 
     glVertexPointer(3, GL_FLOAT, 0, 0)); 

     // enable vertex arrays 
     glEnableClientState(GL_VERTEX_ARRAY); 
     glEnableClientState(GL_COLOR_ARRAY); 

     glDrawArrays(GL_POINT, 0, 640*480); 

     glDisableClientState(GL_VERTEX_ARRAY); // disable vertex arrays 
     glDisableClientState(GL_COLOR_ARRAY); 

     glBindBuffer(GL_ARRAY_BUFFER_ARB, 0); 

    glPopMatrix(); 

    glutSwapBuffers(); 
} 

Answer 1

PS: Program kullanıma, ama göremiyorum İşte simpflified koddur Vertex Array sürümüyle karşılaştırıldığında ortalama performanstaki herhangi bir gelişme. Bu iyi mi? SORUN ÇÖZÜLDÜ.

1 - I though that glGenBuffers first parameter was the number that 
would be associated to the buffer, instead, its the number of 
buffers that would be allocated. This doesn't matter anyway, because 
now I'm using a single buffer and adding all the data to it. Didn't 
solved the problem, but was going in the right way. 

2 - There are two ways of being able to use OpenGL VBO functions. 
First, you can bind the ARB version functions by yourself OR you 
can add glew.h and use glewInit() after starting an OpenGL context. 
The second option is a LOT cleaner and I changed my code so I don't 
use the ARB versions anymore. Still didn't solved the problem. 

3 - Christian Rau asked me for glErrors in the code, so, I wrote it 
after each OpenGL operation in displayCB. After glDrawArrays I got 
an 0x00500 error, that means there is an invalid enum, so I noticed 
I was using GL_POINT as parameter to glDrawArrays, instead of 
GL_POINTS, so silly that makes me want to kill myself. 

son kod:

//EDIT: Added glew.h as a header and I´m not using the ARB version anymore 
#include <glew.h> 

    int main() 
    { 
     //Declaring variables, initiating glut, setting camera and checking the compatibility as http://www.songho.ca/opengl/gl_vbo.html 
     glutDisplayFunc(displayCB); 
     glutIdleFunc(displayCB); 
     ... 

     //EDIT: IS VERY IMPORTANT TO ADD IT AS SOON AS YOU START AN OPENGL CONTEXT. 
     initGlew(); 

     //Inittiating the vertex buffers 
     if(vboSupported) 
     { 
      //EDIT: I was using two buffers, one for color and another for the vertex. I changed the code so I use a single buffer now. 
      //EDIT: Notice that I'm not using the ARB version of the functions anymore. 
      glGenBuffers(1, &buffer); 
      glBindBuffer(GL_ARRAY_BUFFER_ARB, buffer); 
      glBufferData(GL_ARRAY_BUFFER_ARB, (sizeof(GLfloat) * 640 * 480 * 3) + (sizeof(GLbyte) * 640 * 480 * 3), 0, GL_STREAM_DRAW_ARB); 
     } 
     //glutMainLoop(), cleaning memory, ending main 
     .. 
    } 

    //Updating the screen 
    void displayCB() 
    { 
     point_cloud.update(); 

     // clear buffer 
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT); 

     // save the initial ModelView matrix before modifying ModelView matrix 
     glPushMatrix(); 

      glBindBuffer(GL_ARRAY_BUFFER_ARB, buffer); 
      glBufferSubData(GL_ARRAY_BUFFER_ARB, 0, (sizeof(char) * 640 * 480 * 3), point_cloud.points_color); 
      glBufferSubData(GL_ARRAY_BUFFER_ARB, (sizeof(char) * 640 * 480 * 3), (sizeof(float) * 640 * 480 * 3), point_cloud.points_position); 

      // enable vertex arrays 
      glEnableClientState(GL_VERTEX_ARRAY); 
      glEnableClientState(GL_COLOR_ARRAY); 

      glColorPointer(3, GL_UNSIGNED_BYTE, 0, 0); 
      //EDIT: Added the right offset at the vertex pointer position 
      glVertexPointer(3, GL_FLOAT, 0, (void*)(sizeof(char) * 640 * 480 * 3)); 

      //EDIT: Was using GL_POINT instead of GL_POINTS 
      glDrawArrays(GL_POINTS, 0, 640*480); 

      glDisableClientState(GL_VERTEX_ARRAY); // disable vertex arrays 
      glDisableClientState(GL_COLOR_ARRAY); 

      glBindBuffer(GL_ARRAY_BUFFER_ARB, 0); 

     glPopMatrix(); 

     glutSwapBuffers(); 
    }