VBO不会显示（sdl与glew）

Question

我刚开始使用VBOs（使用SDL/glew）。我试图从一个立方体的简单例子开始 - 实际上此刻只是一个立方体的一个面 - 但我不能得到任何东西来显示

我的顶点结构定义如下：

struct Vertex 
{ 
float x, y, z;   //Vertex coords 
float tx, ty;   //Texture coords 
float nx, ny, nz;  //Normal coords 
}; 

立方体然后，像这样产生的：

 Vertex temp; 

     //NOTE: Perspective is from looking at the cube from the outside 
    //Just trying to display one face for the moment to simplify 
     //Back face ------------------------------------------------------------------------------------------ 
     temp.x = 0.f; temp.y = 0.f; temp.z = 0.f;  //Bottom Right - 0 
     temp.nx = 0.f; temp.ny = 0.f; temp.nz = 1.f; // This stays the same for the rest of the face 
     temp.tx = 1.f; temp.ty = 0.f; 
     m_vertices.push_back(temp); 

     temp.x = 0.f; temp.y = m_fHeight; temp.z = 0.f;   //Top Right - 1 
     temp.tx = 1.f; temp.ty = 1.f; 
     m_vertices.push_back(temp); 

     temp.x = m_fWidth; temp.y = m_fHeight; temp.z = 0.f; //Top Left  - 2 
     temp.tx = 0.f; temp.ty = 1.f; 
     m_vertices.push_back(temp); 

     temp.x = m_fWidth; temp.y = 0.f; temp.z = 0.f; //Bottom Left - 3 
     temp.tx = 0.f; temp.ty = 0.f; 
     m_vertices.push_back(temp); 

     m_indeces.push_back(0); m_indeces.push_back(1); m_indeces.push_back(2); 
     m_indeces.push_back(2); m_indeces.push_back(3); m_indeces.push_back(0); 


     //Generate the vertex buffer 
     glGenBuffers(1, &m_vertexBufferID); 
     //Bind the vertex buffer                         
     glBindBuffer(GL_ARRAY_BUFFER, m_vertexBufferID); 
     //Fill the vertex buffer - size is 24*sizeof(Vertex) bcs 6 faces with 4 corners 
     glBufferData(GL_ARRAY_BUFFER, sizeof(Vertex) * 4, NULL, GL_STATIC_DRAW); 
     glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(Vertex) * 4, &m_vertices); // Actually upload the data 

     //Set up the pointers 
     glTexCoordPointer(2, GL_FLOAT, sizeof(Vertex), BUFFER_OFFSET(12)); 
     glNormalPointer(GL_FLOAT, sizeof(Vertex), BUFFER_OFFSET(20)); 
     glVertexPointer(3, GL_FLOAT, sizeof(Vertex), BUFFER_OFFSET(0)); 


     //Generate the index buffer 
     glGenBuffers(1, &m_indexBufferID);          
     //Bind the index buffer                       
     glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m_indexBufferID); 
     //Fill the index buffer- size is 36*sizeof(uint) bcs 6 traingle coords in 1 face * 6 faces 
     glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(GLubyte) * 6, NULL, GL_STATIC_DRAW); 
     glBufferSubData(GL_ELEMENT_ARRAY_BUFFER, 0, sizeof(GLubyte) * 6, &m_indeces); // Actually upload the data 

然后将其发送在一个单独的函数来呈现：

glBindBuffer(GL_ARRAY_BUFFER, vertexID); 
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexID); 

glEnableClientState(GL_TEXTURE_COORD_ARRAY); 
glEnableClientState(GL_NORMAL_ARRAY); 
glEnableClientState(GL_VERTEX_ARRAY); 

// Resetup the pointers. 
glTexCoordPointer(2, GL_FLOAT, sizeof(Vertex), BUFFER_OFFSET(12)); 
glNormalPointer(GL_FLOAT, sizeof(Vertex), BUFFER_OFFSET(20)); 
glVertexPointer(3, GL_FLOAT, sizeof(Vertex), BUFFER_OFFSET(0)); 

//Draw the indexed elements 
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_BYTE, BUFFER_OFFSET(0)); 

glDisableClientState(GL_TEXTURE_COORD_ARRAY); 
glDisableClientState(GL_NORMAL_ARRAY); 
glDisableClientState(GL_VERTEX_ARRAY); 

和BUFFER_OFFSET（）是一个simaple宏定义为：

// A helper macro to get a position 
#define BUFFER_OFFSET(i) ((char *)NULL + (i)) 

但我不能得到任何显示 - 应用相同的纹理等以直接模式的立方体显示了罚款。

奇怪的是偶尔会有一些非常奇怪的东西被显示出来，每次都会有所不同 - 也许这是某种初始化错误？

Answer 1

你的大小都不符合评论，我怀疑你读了VBO的结尾。

Answer 2

Huzzah !!更改&m_vertices和&m_indeces到m_vertices和m_indeces在呼叫glBufferSubData()工作！

a-thank-yoh！