每次调用glBindBuffer时都需要glVertexAttribPointer？

Question

在OpenGL（特别是OpenGL ES 2.0）中，每次绑定一个新的VBO时，都需要调用glVertexAttribPointer？

例如：

glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer1); 

glVertexAttribPointer(ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, sizeof(vertexStruct), (void*)offsetof(vertexStruct,position)); 
glEnableVertexAttribArray(ATTRIB_POSITION); 
glVertexAttribPointer(ATTRIB_COLOR, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(vertexStruct), (void*)offsetof(vertexStruct,color); 
glEnableVertexAttribArray(ATTRIB_COLOR); 

glDrawElements(GL_TRIANGLE_STRIP, sizeof(indices)/sizeof(GLubyte), GL_UNSIGNED_BYTE, (void*)0); 

// If vertexBuffer2 has the exact same attributes as vertexBuffer1 
// is this legal or do the calls to glVertexAttribPointer (and glEnableVertexAttribArray) 
// required again? 

glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer2); 
glDrawElements(GL_TRIANGLE_STRIP, sizeof(indices)/sizeof(GLubyte), GL_UNSIGNED_BYTE, (void*)0); 

我知道有该地址不必调用glVertexAttribPointer VAOs，但我想知道如果这是确定在OpenGL办？

Answer 1

如果你这样做：

glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer1); 

glVertexAttribPointer(ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, sizeof(vertexStruct), (void*)offsetof(vertexStruct,position)); 
glEnableVertexAttribArray(ATTRIB_POSITION); 
glVertexAttribPointer(ATTRIB_COLOR, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(vertexStruct), (void*)offsetof(vertexStruct,color); 
glEnableVertexAttribArray(ATTRIB_COLOR); 

glBindBuffer(GL_ARRAY_BUFFER, 0); 

glDrawElements(GL_TRIANGLE_STRIP, sizeof(indices)/sizeof(GLubyte), GL_UNSIGNED_BYTE, (void*)0); 

您的代码会工作得很好。所有gl*Pointer调用要做的是查看当函数调用时存储在GL_ARRAY_BUFFER中的内容，并在该缓冲区和该属性之间创建关联。因此，更改用于属性的缓冲区的唯一方法是调用gl*Pointer。