/* * Copyright (c) 1993-1997, 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 * Unpublished-- rights reserved under the copyright laws of the * United States.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(R) is a registered trademark of Silicon Graphics, Inc. */ /* * alpha3D.c * This program demonstrates how to intermix opaque and * alpha blended polygons in the same scene, by using * glDepthMask. Press the 'a' key to animate moving the * transparent object through the opaque object. Press * the 'r' key to reset the scene. */ #include <stdlib.h> #include <stdio.h> #include <GL/glut.h> #define MAXZ 8.0 #define MINZ -8.0 #define ZINC 4. static float solidZ = MAXZ; static float transparentZ = MINZ; static GLuint sphereList, cubeList; static void init(void) { GLfloat mat_specular[] = { 1.0, 1.0, 1.0, 0.15 }; GLfloat mat_shininess[] = { 100.0 }; GLfloat position[] = { 0.5, 0.5, 1.0, 0.0 }; glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular); glMaterialfv(GL_FRONT, GL_SHININESS, mat_shininess); glLightfv(GL_LIGHT0, GL_POSITION, position); glEnable(GL_LIGHTING); glEnable(GL_LIGHT0); glEnable(GL_DEPTH_TEST); sphereList = glGenLists(1); glNewList(sphereList, GL_COMPILE); glutSolidSphere (0.4, 16, 16); glEndList(); cubeList = glGenLists(1); glNewList(cubeList, GL_COMPILE); glutSolidCube (0.6); glEndList(); } static void display(void) { GLfloat mat_solid[] = { 0.75, 0.75, 0.0, 1.0 }; GLfloat mat_zero[] = { 0.0, 0.0, 0.0, 1.0 }; GLfloat mat_transparent[] = { 0.0, 0.8, 0.8, 0.6 }; GLfloat mat_emission[] = { 0.0, 0.3, 0.3, 0.6 }; glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glPushMatrix (); glTranslatef (-0.15, -0.15, solidZ); glMaterialfv(GL_FRONT, GL_EMISSION, mat_zero); glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_solid); glCallList (sphereList); glPopMatrix (); glPushMatrix (); glTranslatef (0.15, 0.15, transparentZ); glRotatef (15.0, 1.0, 1.0, 0.0); glRotatef (30.0, 0.0, 1.0, 0.0); glMaterialfv(GL_FRONT, GL_EMISSION, mat_emission); glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_transparent); glEnable (GL_BLEND); glDepthMask (GL_FALSE); glBlendFunc (GL_SRC_ALPHA, GL_ONE); glCallList (cubeList); glDepthMask (GL_TRUE); glDisable (GL_BLEND); glPopMatrix (); glutSwapBuffers(); } static void reshape(int w, int h) { glViewport(0, 0, (GLint) w, (GLint) h); glMatrixMode(GL_PROJECTION); glLoadIdentity(); if (w <= h) glOrtho (-1.5, 1.5, -1.5*(GLfloat)h/(GLfloat)w, 1.5*(GLfloat)h/(GLfloat)w, -10.0, 10.0); else glOrtho (-1.5*(GLfloat)w/(GLfloat)h, 1.5*(GLfloat)w/(GLfloat)h, -1.5, 1.5, -10.0, 10.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); } static void animate(void) { static double t0 = -1.; if (solidZ <= MINZ || transparentZ >= MAXZ) { glutIdleFunc(NULL); t0 = -1.; } else { double t, dt; t = glutGet(GLUT_ELAPSED_TIME) / 1000.; if (t0 < 0.) t0 = t; dt = t - t0; t0 = t; solidZ -= ZINC*dt; transparentZ += ZINC*dt; glutPostRedisplay(); } } /* ARGSUSED1 */ static void keyboard(unsigned char key, int x, int y) { switch (key) { case 'a': case 'A': solidZ = MAXZ; transparentZ = MINZ; glutIdleFunc(animate); break; case 'r': case 'R': solidZ = MAXZ; transparentZ = MINZ; glutPostRedisplay(); break; case 27: exit(0); } } int main(int argc, char** argv) { glutInit(&argc, argv); glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH); glutInitWindowSize(500, 500); glutCreateWindow(argv[0]); init(); glutReshapeFunc(reshape); glutKeyboardFunc(keyboard); glutDisplayFunc(display); glutMainLoop(); return 0; }