Opengl VBO赢得';t显示(带glew的sdl)
我刚开始使用VBOs(使用SDL/glew)。我试着从一个简单的立方体开始——实际上目前只是立方体的一个面——但我无法显示任何东西 我的顶点结构定义如下:Opengl VBO赢得';t显示(带glew的sdl),opengl,sdl,vbo,glew,Opengl,Sdl,Vbo,Glew,我刚开始使用VBOs(使用SDL/glew)。我试着从一个简单的立方体开始——实际上目前只是立方体的一个面——但我无法显示任何东西 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 }; 然后生成多维数据集,如下所示: Vertex
struct Vertex
{
float x, y, z; //Vertex coords
float tx, ty; //Texture coords
float nx, ny, nz; //Normal coords
};
然后生成多维数据集,如下所示:
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
然后将其发送到单独的函数中进行渲染:
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);
BUFFER_OFFSET()是一个simaple宏,定义如下:
// A helper macro to get a position
#define BUFFER_OFFSET(i) ((char *)NULL + (i))
但我就是无法显示任何东西——在即时模式下对立方体应用相同的纹理等,效果很好
奇怪的是,有时会显示一些非常奇怪的东西,每次都不一样-所以可能是某种初始化错误?您的大小都与注释不匹配,我怀疑您正在读取VBO的结尾。Huzzah!!在调用
glBufferSubData()
的过程中,将&m_顶点
和&m_索引
更改为m_顶点
和m_索引
,成功了
谢谢你 “index”的复数形式是“index”或“index”。glGetError()告诉你什么?如果VBOs不为你工作,那么
glDraweElements
是什么?顺便说一句,offsetof
(这是一个标准提供的宏)将比BUFFER\u OFFSET
好得多。glGetError()似乎返回了GL\u NO\u ERRORHi,很抱歉,我显然忘了添加注释-我认为大小是正确的,因为我目前只尝试渲染一个面,应该用4个顶点结构来描述(注释中说24,因为对于完整的立方体x6面),索引的数量也是一样的