iOS Game Development

166 5. OpenGL ES: Turbocharged!

glVertexPointer (GLint size, GLenum type, GLsizei stride,

const GLvoid *pointer). e rst parameter species how many compo-

nents a vertex possesses. (is is not at once clear from the array, so we need to

specify it explicitly.) Possible values are 2, 3, and 4. en you give the data type

of the elements. OpenGL supplies a suitable constant for each data type. Since

wehave declared the array as GLshort, we choose the constant GL_SHORT. You

probably know that a data type determines how much space an element occupies

in memory. Sothat OpenGL can iterate through all the elements of an array, we

must specify how ...