BuffersGL 1.5

glBindBuffer

Makes a buffer the current one for a given target, so later buffer calls act on it.

Part of the family glBind*

Signature

void glBindBuffer(GLenum target, GLuint buffer);

How it works

OpenGL is a state machine: most functions do not take the object they operate on as a parameter. Instead, you first "bind" the object to a slot (the target), and every later call that uses that slot affects whatever is bound there.

glBindBuffer puts a buffer into one of those slots. After glBindBuffer(GL_ARRAY_BUFFER, vbo), a call like glBufferData(GL_ARRAY_BUFFER, ...) uploads data into vbo.

Parameters

targetGLenum

Which slot to bind to. It defines how the buffer will be used.

Common values

GL_ARRAY_BUFFER: Vertex attributes (positions, colors, UVs…).
GL_ELEMENT_ARRAY_BUFFER: Indices for glDrawElements. This binding is stored in the current VAO.
GL_UNIFORM_BUFFER: Uniform blocks shared between shaders.
GL_SHADER_STORAGE_BUFFER: Read/write storage for shaders (GL 4.3).
GL_COPY_READ_BUFFER / GL_COPY_WRITE_BUFFER: Scratch slots for buffer-to-buffer copies.

bufferGLuint

The buffer ID, or 0 to unbind whatever is in the slot.

Tips & pitfalls

Never unbind GL_ELEMENT_ARRAY_BUFFER while a VAO is bound — the VAO remembers it, and unbinding erases the index buffer from the VAO.
GL_ARRAY_BUFFER is NOT stored in the VAO; what is stored is the buffer captured by each glVertexAttribPointer call.

Errors

When the call is invalid it does nothing and sets an error, which glGetError returns:

GL_INVALID_ENUM: target is not an accepted value.
GL_INVALID_VALUE: buffer was never returned by glGenBuffers.

Example

example.cpp

1glBindBuffer(GL_ARRAY_BUFFER, vbo);
2glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
3glBindBuffer(GL_ARRAY_BUFFER, 0); // optional: unbind

Official Khronos documentation