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Table of Contents
glOrtho - multiply the current matrix with an orthographic matrix
void glOrtho( GLdouble left,
GLdouble right,
GLdouble bottom,
GLdouble top,
GLdouble near_val,
GLdouble far_val )
- left, right
- Specify the coordinates for the left and right vertical
clipping planes.
- bottom, top
- Specify the coordinates for the bottom and
top horizontal clipping planes.
- near_val, far_val
- Specify the distances
to the nearer and farther depth clipping planes. These values are negative
if the plane is to be behind the viewer.
glOrtho describes a
transformation that produces a parallel projection. The current matrix (see
glMatrixMode) is multiplied by this matrix and the result replaces the
current matrix, as if glMultMatrix were called with the following matrix
as its argument:
eqn not supported
where
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eqn not supported
eqn not supported
Typically, the matrix mode is GL_PROJECTION, and (left,
bottom, -near_val) and (right, top, -near_val) specify the points on the
near clipping plane that are mapped to the lower left and upper right corners
of the window, respectively, assuming that the eye is located at (0, 0,
0). -far_val specifies the location of the far clipping plane. Both near_val
and far_val can be either positive or negative.
Use glPushMatrix and glPopMatrix
to save and restore the current matrix stack.
GL_INVALID_OPERATION
is generated if glOrtho is executed between the execution of glBegin and
the corresponding execution of glEnd.
glGet with argument
GL_MATRIX_MODE
glGet with argument GL_COLOR_MATRIX
glGet with argument GL_MODELVIEW_MATRIX
glGet with argument GL_PROJECTION_MATRIX
glGet with argument GL_TEXTURE_MATRIX
glFrustum(3G)
, glMatrixMode(3G)
,
glMultMatrix(3G)
, glPushMatrix(3G)
, glViewport(3G)
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