# glclipplane(3g) [xfree86 man page]

GLCLIPPLANE(3G) GLCLIPPLANE(3G)NAME

glClipPlane - specify a plane against which all geometry is clippedC SPECIFICATION

void glClipPlane( GLenum plane, const GLdouble *equation )PARAMETERS

plane Specifies which clipping plane is being positioned. Symbolic names of the form GL_CLIP_PLANEi, where i is an integer between 0 and GL_MAX_CLIP_PLANES-1, are accepted. equation Specifies the address of an array of four double-precision floating-point values. These values are interpreted as a plane equa- tion.DESCRIPTION

Geometry is always clipped against the boundaries of a six-plane frustum in x, y, and z. glClipPlane allows the specification of addi- tional planes, not necessarily perpendicular to the x, y, or z axis, against which all geometry is clipped. To determine the maximum num- ber of additional clipping planes, call glGetIntegerv with argument GL_MAX_CLIP_PLANES. All implementations support at least six such clip- ping planes. Because the resulting clipping region is the intersection of the defined half-spaces, it is always convex. glClipPlane specifies a half-space using a four-component plane equation. When glClipPlane is called, equation is transformed by the inverse of the modelview matrix and stored in the resulting eye coordinates. Subsequent changes to the modelview matrix have no effect on the stored plane-equation components. If the dot product of the eye coordinates of a vertex with the stored plane equation components is positive or zero, the vertex is in with respect to that clipping plane. Otherwise, it is out. To enable and disable clipping planes, call glEnable and glDisable with the argument GL_CLIP_PLANEi, where i is the plane number. All clipping planes are initially defined as (0, 0, 0, 0) in eye coordinates and are disabled.NOTES

It is always the case that GL_CLIP_PLANEi = GL_CLIP_PLANE0+i.ERRORS

GL_INVALID_ENUM is generated if plane is not an accepted value. GL_INVALID_OPERATION is generated if glClipPlane is executed between the execution of glBegin and the corresponding execution of glEnd.ASSOCIATED GETS

glGetClipPlane glIsEnabled with argument GL_CLIP_PLANEiSEE ALSO

glEnable(3G) GLCLIPPLANE(3G)

## Check Out this Related Man Page

GLORTHO(3G) GLORTHO(3G)NAME

glOrtho - multiply the current matrix with an orthographic matrixC SPECIFICATION

void glOrtho( GLdouble left, GLdouble right, GLdouble bottom, GLdouble top, GLdouble near_val, GLdouble far_val )PARAMETERS

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.DESCRIPTION

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: __________ 0 0 tx ( 0 __________ 0 ty) 0 0 ________________ tz 0 0 0 1 where tx=-__________ ty=-__________ tz=-________________ 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).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.-far_valERRORS

GL_INVALID_OPERATION is generated if glOrtho is executed between the execution of glBegin and the corresponding execution of glEnd.ASSOCIATED GETS

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_MATRIXSEE ALSO

glFrustum(3G), glMatrixMode(3G), glMultMatrix(3G), glPushMatrix(3G), glViewport(3G) GLORTHO(3G)