c++ - OpenGL VBO 不工作(C++)

Question

当我尝试使用 VBO + 索引绘制三角形时，它不起作用

   vertices.push_back(0.5f);
   vertices.push_back(-0.5f);
   vertices.push_back(-2.0f);
   vertices.push_back(-0.5f);
   vertices.push_back(-0.5f);
   vertices.push_back(-2.0f);
   vertices.push_back(0.5f);
   vertices.push_back(-0.5f);
   vertices.push_back(-2.0f);

   indices.push_back(0);
   indices.push_back(1);
   indices.push_back(2);


   GLuint bufferID,bufferID2;

   glGenBuffers(1,&bufferID);
   glGenBuffers(1,&bufferID2);
   glBindBuffer(GL_ARRAY_BUFFER,bufferID);
   glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,bufferID2);
   glBufferData(GL_ARRAY_BUFFER,sizeof(GLfloat)*3,&vertices[0],GL_STATIC_DRAW);

   glEnableClientState(GL_VERTEX_ARRAY);

   glVertexPointer(3,GL_FLOAT,0,0);
   glDrawElements(GL_TRIANGLES,indices.size(),GL_UNSIGNED_INT,&indices[0]);

   glDisableClientState(GL_VERTEX_ARRAY);

   glDeleteBuffers(1,&bufferID);
   glDeleteBuffers(1,&bufferID2);

但是用 VBO 画一个点是可行的

vertices.push_back(0.5f);
vertices.push_back(-0.5f);
vertices.push_back(-2.0f);

GLuint bufferID;

glGenBuffers(1,&bufferID);
glBindBuffer(GL_ARRAY_BUFFER,bufferID);
glBufferData(GL_ARRAY_BUFFER,sizeof(GLfloat)*3,&vertices[0],GL_STATIC_DRAW);



glEnableClientState(GL_VERTEX_ARRAY);
glVertexPointer(3,GL_FLOAT,0,0);

glPointSize(100.0f);
glDrawArrays(GL_POINTS,0,1);
glDisableClientState(GL_VERTEX_ARRAY);

glDeleteBuffers(1,&bufferID);

我已经通读了一些教程和其他帖子，但没有任何效果。 mby 我没有正确使用索引？

谁能帮我解决这个问题？

Answer 1

你只传递 3 个 float 给你想传递更多的 VBO:

glBufferData(GL_ARRAY_BUFFER,sizeof(GLfloat)*vertices.size(),&vertices[0],GL_STATIC_DRAW);

并且当您绑定(bind)了 GL_ELEMENT_ARRAY_BUFFER 时，glDrawElements 中的 void* 是相对于绑定(bind)缓冲区的:

glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(GLuint)*indices.size(), &indices[0], GL_STATIC_DRAW);

glDrawElements(GL_TRIANGLES, indices.size(), GL_UNSIGNED_INT, 0);

并在遇到问题时始终检查 glGetError，这将有助于了解您从哪些调用开始出错。