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#
# Copyright (c) Mark J. Kilgard, 1994. */
#
#
# (c) Copyright 1993, Silicon Graphics, Inc.
# ALL RIGHTS RESERVED
# Permission to use, copy, modify, and distribute this software for
# any purpose and without fee is hereby granted, provided that the above
# copyright notice appear in all copies and that both the copyright notice
# and this permission notice appear in supporting documentation, and that
# the name of Silicon Graphics, Inc. not be used in advertising
# or publicity pertaining to distribution of the software without specific,
# written prior permission.
#
# THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
# AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
# INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
# FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL SILICON
# GRAPHICS, INC. BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
# SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
# KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
# LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
# THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC. HAS BEEN
# ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
# ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
# POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
#
# US Government Users Restricted Rights
# Use, duplication, or disclosure by the Government is subject to
# restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
# (c)(1)(ii) of the Rights in Technical Data and Computer Software
# clause at DFARS 252.227-7013 and/or in similar or successor
# clauses in the FAR or the DOD or NASA FAR Supplement.
# Unpublished-- rights reserved under the copyright laws of the
# United States. Contractor/manufacturer is Silicon Graphics,
# Inc., 2011 N. Shoreline Blvd., Mountain View, CA 94039-7311.
#
# OpenGL(TM) is a trademark of Silicon Graphics, Inc.
#
# pickdepth.c
# Picking is demonstrated in this program. In
# rendering mode, three overlapping rectangles are
# drawn. When the left mouse button is pressed,
# selection mode is entered with the picking matrix.
# Rectangles which are drawn under the cursor position
# are "picked." Pay special attention to the depth
# value range, which is returned.
require 'opengl'
include Gl,Glu,Glut
def myinit
glClearColor(0.0, 0.0, 0.0, 0.0)
glDepthFunc(GL_LESS)
glEnable(GL_DEPTH_TEST)
glShadeModel(GL_FLAT)
glDepthRange(0.0, 1.0) #/* The default z mapping */
end
# The three rectangles are drawn. In selection mode,
# each rectangle is given the same name. Note that
# each rectangle is drawn with a different z value.
def drawRects(mode)
if (mode == GL_SELECT)
glLoadName(1)
end
glBegin(GL_QUADS)
glColor(1.0, 1.0, 0.0)
glVertex(2, 0, 0)
glVertex(2, 6, 0)
glVertex(6, 6, 0)
glVertex(6, 0, 0)
glEnd()
if (mode == GL_SELECT)
glLoadName(2)
end
glBegin(GL_QUADS)
glColor(0.0, 1.0, 1.0)
glVertex(3, 2, -1)
glVertex(3, 8, -1)
glVertex(8, 8, -1)
glVertex(8, 2, -1)
glEnd()
if (mode == GL_SELECT)
glLoadName(3)
end
glBegin(GL_QUADS)
glColor(1.0, 0.0, 1.0)
glVertex(0, 2, -2)
glVertex(0, 7, -2)
glVertex(5, 7, -2)
glVertex(5, 2, -2)
glEnd()
end
# processHits() prints out the contents of the
# selection array.
def processHits(hits, buffer)
printf("hits = %d\n", hits)
ptr = buffer.unpack("I*")
p = 0
for i in 0...hits # for each hit
names = ptr[p]
printf(" number of names for hit = %d\n", names); p+=1
printf(" z1 is %g", ptr[p].to_f/0xffffffff); p+=1
printf(" z2 is %g\n", ptr[p].to_f/0xffffffff); p+=1
printf(" the name is ")
for j in 0...names # for each name
printf("%d ", ptr[p]) ; p+=1
end
printf("\n")
end
end
# pickRects() sets up selection mode, name stack,
# and projection matrix for picking. Then the objects
# are drawn.
BUFSIZE=512
pickRects = proc do |button, state, x, y|
if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN)
viewport = glGetDoublev(GL_VIEWPORT)
selectBuf = glSelectBuffer(BUFSIZE)
glRenderMode(GL_SELECT)
glInitNames()
glPushName(~0)
glMatrixMode(GL_PROJECTION)
glPushMatrix()
glLoadIdentity()
# create 5x5 pixel picking region near cursor location
gluPickMatrix( x, viewport[3] - y, 5.0, 5.0, viewport)
glOrtho(0.0, 8.0, 0.0, 8.0, -0.5, 2.5)
drawRects(GL_SELECT)
glPopMatrix()
glFlush()
hits = glRenderMode(GL_RENDER)
processHits(hits, selectBuf)
end
end
display = proc do
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
drawRects(GL_RENDER)
glutSwapBuffers()
end
myReshape = proc do |w, h|
glViewport(0, 0, w, h)
glMatrixMode(GL_PROJECTION)
glLoadIdentity()
glOrtho(0.0, 8.0, 0.0, 8.0, -0.5, 2.5)
glMatrixMode(GL_MODELVIEW)
glLoadIdentity()
end
keyboard = Proc.new do |key, x, y|
case (key)
when ?\e
exit(0)
end
end
# Main Loop
# Open window with initial window size, title bar,
# RGBA display mode, depth buffer, and handle input events.
glutInitWindowSize(500, 500)
glutInitWindowPosition(100, 100)
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH)
glutInit()
glutCreateWindow()
myinit()
glutMouseFunc(pickRects)
glutReshapeFunc(myReshape)
glutDisplayFunc(display)
glutKeyboardFunc(keyboard)
glutMainLoop()
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