blob: 014aaa071a51efaf28a531b7cc108c15eb5e4bb5 [file] [log] [blame]
/*
* 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* Unpublished-- rights reserved under the copyright laws of the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.
*/
#include <GL/glut.h>
#include <stdlib.h>
#include <stdio.h>
static int leftFirst = GL_TRUE;
static struct { GLenum func; const char *str; } funcs[] =
{
{ GL_LESS, "GL_LESS" },
{ GL_LEQUAL, "GL_LEQUAL" },
{ GL_GREATER, "GL_GREATER" },
{ GL_GEQUAL, "GL_GEQUAL" },
{ GL_EQUAL, "GL_EQUAL" },
{ GL_NOTEQUAL, "GL_NOTEQUAL" },
{ GL_ALWAYS, "GL_ALWAYS" },
{ GL_NEVER, "GL_NEVER" },
};
#define NUM_FUNCS (sizeof(funcs) / sizeof(funcs[0]))
static int curFunc = 0;
static double clearVal = 1.0;
static float minZ = 0.0;
static float maxZ = 1.0;
static void usage(void)
{
printf("t - toggle rendering order of triangles\n");
printf("c - toggle Z clear value between 0, 1\n");
printf("f - cycle through depth test functions\n");
printf("n/N - decrease/increase depthrange minZ\n");
printf("x/X - decrease/increase depthrange maxZ\n");
printf("spc - reset\n");
printf("z - set to reverse-direction (ztrick) mode\n");
fflush(stdout);
}
static void init(void)
{
glEnable(GL_DEPTH_TEST);
glClearColor (1.0, 0.0, 0.0, 0.0);
}
static void drawLeftTriangle(void)
{
/* draw yellow triangle on LHS of screen */
glBegin (GL_TRIANGLES);
glColor4f(1.0, 1.0, 0.0, 0.75);
glVertex3f(0.1, 0.9, -1.0);
glVertex3f(0.1, 0.1, -1.0);
glVertex3f(0.8, 0.5, 1.0);
glEnd();
}
static void drawRightTriangle(void)
{
/* draw cyan triangle on RHS of screen */
glBegin (GL_TRIANGLES);
glColor4f(0.0, 1.0, 1.0, 0.75);
glVertex3f(0.9, 0.9, 0.0);
glVertex3f(0.2, 0.5, 0.0);
glVertex3f(0.9, 0.1, 0.0);
glEnd();
}
void display(void)
{
printf("GL_CLEAR_DEPTH = %.2f, GL_DEPTH_FUNC = %s, DepthRange(%.1f, %.1f)\n",
clearVal, funcs[curFunc].str, minZ, maxZ);
fflush(stdout);
glClearDepth(clearVal);
glDepthRange(minZ, maxZ);
glDepthFunc(funcs[curFunc].func);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
if (leftFirst) {
drawLeftTriangle();
drawRightTriangle();
}
else {
drawRightTriangle();
drawLeftTriangle();
}
glFlush();
}
void reshape(int w, int h)
{
glViewport(0, 0, (GLsizei) w, (GLsizei) h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
if (w <= h)
gluOrtho2D (0.0, 1.0, 0.0, 1.0*(GLfloat)h/(GLfloat)w);
else
gluOrtho2D (0.0, 1.0*(GLfloat)w/(GLfloat)h, 0.0, 1.0);
}
/* ARGSUSED1 */
void keyboard(unsigned char key, int x, int y)
{
switch (key) {
case 'n':
minZ -= .1;
break;
case 'N':
minZ += .1;
break;
case 'x':
maxZ -= .1;
break;
case 'X':
maxZ += .1;
break;
case 'c':
case 'C':
clearVal = 1.0 - clearVal;
break;
case 'f':
case 'F':
curFunc = (curFunc + 1) % NUM_FUNCS;
break;
case 't':
case 'T':
leftFirst = !leftFirst;
break;
case ' ':
curFunc = 0;
clearVal = 1.0;
minZ = 0.0;
maxZ = 1.0;
break;
case 'z':
curFunc = 2;
clearVal = 0.0;
minZ = 1.0;
maxZ = 0.0;
break;
case 27: /* Escape key */
exit(0);
break;
default:
return;
}
glutPostRedisplay();
}
/* Main Loop
* Open window with initial window size, title bar,
* RGBA display mode, and handle input events.
*/
int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize (200, 200);
glutCreateWindow (argv[0]);
glutReshapeFunc (reshape);
glutKeyboardFunc (keyboard);
glutDisplayFunc (display);
init();
usage();
glutMainLoop();
return 0;
}