GLVIEWPORT(3gl)
NAME
glViewport - set the viewport
C SPECIFICATION
- void glViewport( GLint x,
- GLint y,
GLsizei width,
GLsizei height )
PARAMETERS
- x, y Specify the lower left corner of the viewport rectangle, in pix
- els. The initial value is (0,0).
- width, height
- Specify the width and height of the viewport. When a GL context is first attached to a window, width and height are set to the dimensions of that window.
DESCRIPTION
- glViewport specifies the affine transformation of x and y from normalized device coordinates to window coordinates. Let (xnd, ynd) be normalized device coordinates. Then the window coordinates (xw, yw) are
computed as follows:
- xw=(xnd+1)(w_i_d2_t_h_)+x
- yw=(ynd+1)(h_e_i_g2_h_t_)+y
- Viewport width and height are silently clamped to a range that depends on the
- implementation. To query this range, call glGet with argument
GL_MAX_VIEWPORT_DIMS
ERRORS
GL_INVALID_VALUE is generated if either width or height is negative.
GL_INVALID_OPERATION is generated if glViewport is executed between the execution of glBegin and the corresponding execution of glEnd.
ASSOCIATED GETS
glGet with argument GL_VIEWPORT
glGet with argument GL_MAX_VIEWPORT_DIMS