/opengles/redbook/stencil.c
http://ftk.googlecode.com/ · C · 174 lines · 99 code · 19 blank · 56 comment · 2 complexity · 717178ace59b95fcf568ff7842ec8b36 MD5 · raw file
- /*
- * License Applicability. Except to the extent portions of this file are
- * made subject to an alternative license as permitted in the SGI Free
- * Software License B, Version 1.1 (the "License"), the contents of this
- * file are subject only to the provisions of the License. You may not use
- * this file except in compliance with the License. You may obtain a copy
- * of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
- * Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
- *
- * http://oss.sgi.com/projects/FreeB
- *
- * Note that, as provided in the License, the Software is distributed on an
- * "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
- * DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
- * CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
- * PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
- *
- * Original Code. The Original Code is: OpenGL Sample Implementation,
- * Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
- * Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
- * Copyright in any portions created by third parties is as indicated
- * elsewhere herein. All Rights Reserved.
- *
- * Additional Notice Provisions: The application programming interfaces
- * established by SGI in conjunction with the Original Code are The
- * OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
- * April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
- * 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
- * Window System(R) (Version 1.3), released October 19, 1998. This software
- * was created using the OpenGL(R) version 1.2.1 Sample Implementation
- * published by SGI, but has not been independently verified as being
- * compliant with the OpenGL(R) version 1.2.1 Specification.
- *
- */
- /*
- * stencil.c
- * This program demonstrates use of the stencil buffer for
- * masking nonrectangular regions.
- * Whenever the window is redrawn, a value of 1 is drawn
- * into a diamond-shaped region in the stencil buffer.
- * Elsewhere in the stencil buffer, the value is 0.
- * Then a blue sphere is drawn where the stencil value is 1,
- * and yellow torii are drawn where the stencil value is not 1.
- */
- #include <GL/glut.h>
- #include <stdlib.h>
- #define YELLOWMAT 1
- #define BLUEMAT 2
- void init (void)
- {
- GLfloat yellow_diffuse[] = { 0.7, 0.7, 0.0, 1.0 };
- GLfloat yellow_specular[] = { 1.0, 1.0, 1.0, 1.0 };
- GLfloat blue_diffuse[] = { 0.1, 0.1, 0.7, 1.0 };
- GLfloat blue_specular[] = { 0.1, 1.0, 1.0, 1.0 };
- GLfloat position_one[] = { 1.0, 1.0, 1.0, 0.0 };
- glNewList(YELLOWMAT, GL_COMPILE);
- glMaterialfv(GL_FRONT, GL_DIFFUSE, yellow_diffuse);
- glMaterialfv(GL_FRONT, GL_SPECULAR, yellow_specular);
- glMaterialf(GL_FRONT, GL_SHININESS, 64.0);
- glEndList();
- glNewList(BLUEMAT, GL_COMPILE);
- glMaterialfv(GL_FRONT, GL_DIFFUSE, blue_diffuse);
- glMaterialfv(GL_FRONT, GL_SPECULAR, blue_specular);
- glMaterialf(GL_FRONT, GL_SHININESS, 45.0);
- glEndList();
- glLightfv(GL_LIGHT0, GL_POSITION, position_one);
- glEnable(GL_LIGHT0);
- glEnable(GL_LIGHTING);
- glEnable(GL_DEPTH_TEST);
- glClearStencil(0x0);
- glEnable(GL_STENCIL_TEST);
- }
- /* Draw a sphere in a diamond-shaped section in the
- * middle of a window with 2 torii.
- */
- void display(void)
- {
- glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
- /* draw blue sphere where the stencil is 1 */
- glStencilFunc (GL_EQUAL, 0x1, 0x1);
- glStencilOp (GL_KEEP, GL_KEEP, GL_KEEP);
- glCallList (BLUEMAT);
- glutSolidSphere (0.5, 15, 15);
- /* draw the tori where the stencil is not 1 */
- glStencilFunc (GL_NOTEQUAL, 0x1, 0x1);
- glPushMatrix();
- glRotatef (45.0, 0.0, 0.0, 1.0);
- glRotatef (45.0, 0.0, 1.0, 0.0);
- glCallList (YELLOWMAT);
- glutSolidTorus (0.275, 0.85, 15, 15);
- glPushMatrix();
- glRotatef (90.0, 1.0, 0.0, 0.0);
- glutSolidTorus (0.275, 0.85, 15, 15);
- glPopMatrix();
- glPopMatrix();
- }
- /* Whenever the window is reshaped, redefine the
- * coordinate system and redraw the stencil area.
- */
- void reshape(int w, int h)
- {
- glViewport(0, 0, (GLsizei) w, (GLsizei) h);
- /* create a diamond shaped stencil area */
- glMatrixMode(GL_PROJECTION);
- glLoadIdentity();
- if (w <= h)
- gluOrtho2D(-3.0, 3.0, -3.0*(GLfloat)h/(GLfloat)w,
- 3.0*(GLfloat)h/(GLfloat)w);
- else
- gluOrtho2D(-3.0*(GLfloat)w/(GLfloat)h,
- 3.0*(GLfloat)w/(GLfloat)h, -3.0, 3.0);
- glMatrixMode(GL_MODELVIEW);
- glLoadIdentity();
- glClear(GL_STENCIL_BUFFER_BIT);
- glStencilFunc (GL_ALWAYS, 0x1, 0x1);
- glStencilOp (GL_REPLACE, GL_REPLACE, GL_REPLACE);
- glBegin(GL_QUADS);
- glVertex2f (-1.0, 0.0);
- glVertex2f (0.0, 1.0);
- glVertex2f (1.0, 0.0);
- glVertex2f (0.0, -1.0);
- glEnd();
- glMatrixMode(GL_PROJECTION);
- glLoadIdentity();
- gluPerspective(45.0, (GLfloat) w/(GLfloat) h, 3.0, 7.0);
- glMatrixMode(GL_MODELVIEW);
- glLoadIdentity();
- glTranslatef(0.0, 0.0, -5.0);
- }
- void keyboard(unsigned char key, int x, int y)
- {
- switch (key) {
- case 27:
- exit(0);
- break;
- }
- }
- /* Main Loop
- * Be certain to request stencil bits.
- */
- int main(int argc, char** argv)
- {
- glutInit(&argc, argv);
- glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB
- | GLUT_DEPTH | GLUT_STENCIL);
- glutInitWindowSize (400, 400);
- glutInitWindowPosition (100, 100);
- glutCreateWindow (argv[0]);
- init ();
- glutReshapeFunc(reshape);
- glutDisplayFunc(display);
- glutKeyboardFunc(keyboard);
- glutMainLoop();
- return 0;
- }