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Vertex Buffer Object 227
Vertex Buffer Object
A Vertex Buffer Object (VBO) is an OpenGL extension that provides methods for uploading data (vertex, normal
vector, color, etc.) to the video device for non-immediate-mode rendering. VBOs offer substantial performance gains
over immediate mode rendering primarily because the data resides in the video device memory rather than the
system memory and so it can be rendered directly by the video device.
The Vertex Buffer Object specification has been standardized by the OpenGL Architecture Review Board [1] as of
OpenGL Version 1.5. Similar functionality was available before the standardization of VBOs via the Nvidia-created
extension "Vertex Array Range" [2] or the ATI's "Vertex Array Object" [3] extension.
Basic VBO functions
The following functions form the core of VBO access and manipulation:
In OpenGL 2.1 [4] :
GenBuffersARB(sizei n, uint *buffers)
Generates a new VBO and returns its ID number as an unsigned integer. Id 0 is reserved.
BindBufferARB(enum target, uint buffer)
Use a previously created buffer as the active VBO.
BufferDataARB(enum target, sizeiptrARB size, const void *data, enum usage)
Upload data to the active VBO.
DeleteBuffersARB(sizei n, const uint *buffers)
Deletes the specified number of VBOs from the supplied array or VBO id.
In OpenGL 3.x [5] and OpenGL 4.x [6] :
GenBuffers(sizei n, uint *buffers)
Generates a new VBO and returns its ID number as an unsigned integer. Id 0 is reserved.
BindBuffer(enum target, uint buffer)
Use a previously created buffer as the active VBO.
BufferData(enum target, sizeiptrARB size, const void *data, enum usage)
Upload data to the active VBO.
DeleteBuffers(sizei n, const uint *buffers)
Deletes the specified number of VBOs from the supplied array or VBO id.
Example usage in C Using OpenGL 2.1
//Initialise VBO - do only once, at start of program
//Create a variable to hold the VBO identifier
GLuint triangleVBO;
//Vertices of a triangle (counter-clockwise winding)
float data[] = {1.0, 0.0, 1.0, 0.0, 0.0, -1.0, -1.0, 0.0, 1.0};
//Create a new VBO and use the variable id to store the VBO id
glGenBuffers(1, &triangleVBO);