Shaders and Programs - Praise for OpenGL ES 30 Programming Guide - page 91

void glUniformBlockBinding (GLuint program ,
GLuint blockIndex ,
GLuint blockBinding )

program handle to the program object
blockIndex index of the uniform block
blockBinding uniform buffer object binding point

Finally, you can bind the uniform buffer object to the GL_UNIFORM_
BUFFER target and a uniform block binding point in the program using
glBindBufferRange or glBindBufferBase .

void glBindBufferRange (GLenum target, GLuint index,
GLuint buffer, GLintptr offset,
GLsizeiptr size )
void glBindBufferBase (GLenum target, GLuint index,
GLuint buffer)

must be GL_UNIFORM_BUFFER or
GL_TRANSFORM_FEEDBACK_BUFFER

target

the binding index

index

the handle to the buffer object

buffer

a starting offset in bytes into the buffer object
( glBindBufferRange only)

offset

the amount of data in bytes that can be read from or written
to the buffer object ( glBindBufferRange only)

size

When programming the uniform blocks, you should pay attention to the
following limitations:

• The maximum number of active uniform blocks used by a vertex
or fragment shader can be queried using glGetIntegerv with
GL_MAX_VERTEX_UNIFORM_BLOCKS or GL_MAX_FRAGMENT_UNIFORM_
BLOCKS , respectively. The minimum supported number for any
implementation is 12.

• The maximum number of combined active uniform blocks used by
all shaders in a program can be queried using glGetIntegerv with
GL_MAX_COMBINED_UNIFORM_BLOCKS . The minimum supported
number for any implementation is 24.