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glGetBufferParameteriv

Name

glGetBufferParameteriv — return parameters of a buffer object

C Specification

void glGetBufferParameteriv(GLenum target,
GLenum value,
GLint * data);

Parameters

target

Specifies the target buffer object. The symbolic constant must be GL_ARRAY_BUFFER or GL_ELEMENT_ARRAY_BUFFER.

value

Specifies the symbolic name of a buffer object parameter. Accepted values are GL_BUFFER_SIZE or GL_BUFFER_USAGE.

data

Returns the requested parameter.

Description

glGetBufferParameteriv returns in data a selected parameter of the buffer object specified by target.

value names a specific buffer object parameter, as follows:

GL_BUFFER_SIZE

params returns the size of the buffer object, measured in bytes. The initial value is 0.

GL_BUFFER_USAGE

params returns the buffer object's usage pattern. The initial value is GL_STATIC_DRAW.

Notes

If an error is generated, no change is made to the contents of data.

Errors

GL_INVALID_ENUM is generated if target or value is not an accepted value.

GL_INVALID_OPERATION is generated if the reserved buffer object name 0 is bound to target.

Examples

Load a vertex buffer into OpenGL for later rendering.
// data_size_in_bytes is the size in bytes of your vertex data.
// data_vertices is your actual vertex data, probably a huge array of floats

GLuint vertex_buffer; // Save this for later rendering
glGenBuffers(1, &vertex_buffer);
glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer);
glBufferData(GL_ARRAY_BUFFER, data_size_in_bytes, 0, GL_STATIC_DRAW);
glBufferSubData(GL_ARRAY_BUFFER, 0, data_size_in_bytes, data_vertices);

GLint size = 0;
glGetBufferParameteriv(GL_ARRAY_BUFFER, GL_BUFFER_SIZE, &size);
if(data_size_in_bytes != size)
{
    glDeleteBuffers(1, &vertex_buffer);
    // Log the error
    return;
}

// Success
Load an index buffer into OpenGL for later rendering.
// data_size_in_bytes is the size in bytes of your vertex data.
// data_indices is an array of integer offsets into your vertex data.

GLuint index_buffer; // Save this for later rendering
glGenBuffers(1, &index_buffer);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, index_buffer);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, data_size_in_bytes, 0, GL_STATIC_DRAW);
glBufferSubData(GL_ELEMENT_ARRAY_BUFFER, 0, data_size_in_bytes, data_indices);

GLint size = 0;
glGetBufferParameteriv(GL_ELEMENT_ARRAY_BUFFER, GL_BUFFER_SIZE, &size);
if(data_size_in_bytes != size)
{
    glDeleteBuffers(1, &index_buffer);
    // Log the error
    return;
}

// Success

See Also

glBindBuffer, glBufferData

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