progs/trivial/tri-mask-tri.c

   1 /*
   2  * Copyright (c) 1991, 1992, 1993 Silicon Graphics, Inc.
   3  *
   4  * Permission to use, copy, modify, distribute, and sell this software and
   5  * its documentation for any purpose is hereby granted without fee, provided
   6  * that (i) the above copyright notices and this permission notice appear in
   7  * all copies of the software and related documentation, and (ii) the name of
   8  * Silicon Graphics may not be used in any advertising or
   9  * publicity relating to the software without the specific, prior written
  10  * permission of Silicon Graphics.
  11  *
  12  * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF
  13  * ANY KIND,
  14  * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
  15  * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
  16  *
  17  * IN NO EVENT SHALL SILICON GRAPHICS BE LIABLE FOR
  18  * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
  19  * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
  20  * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
  21  * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  22  * OF THIS SOFTWARE.
  23  */
  24
  25 #include <stdio.h>
  26 #include <string.h>
  27 #include <stdlib.h>
  28 #include <GL/glut.h>
  29
  30
  31 GLint Width = 250, Height = 250;
  32 GLenum doubleBuffer;
  33 GLint Win;
  34 GLboolean Rmask = GL_TRUE, Gmask = GL_FALSE, Bmask = GL_TRUE;
  35
  36
  37 static void Init(void)
  38 {
  39    fprintf(stderr, "GL_RENDERER   = %s\n", (char *) glGetString(GL_RENDERER));
  40    fprintf(stderr, "GL_VERSION    = %s\n", (char *) glGetString(GL_VERSION));
  41    fprintf(stderr, "GL_VENDOR     = %s\n", (char *) glGetString(GL_VENDOR));
  42    fflush(stderr);
  43    glClearColor(0.0, 0.0, 1.0, 0.0);
  44 }
  45
  46 static void Reshape(int width, int height)
  47 {
  48    glViewport(0, 0, (GLint)width, (GLint)height);
  49    glMatrixMode(GL_PROJECTION);
  50    glLoadIdentity();
  51    glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
  52    glMatrixMode(GL_MODELVIEW);
  53 }
  54
  55 static void Key(unsigned char key, int x, int y)
  56 {
  57    switch (key) {
  58    case 'r':
  59       Rmask = !Rmask;
  60       break;
  61    case 'g':
  62       Gmask = !Gmask;
  63       break;
  64    case 'b':
  65       Bmask = !Bmask;
  66       break;
  67    case 27:
  68       glutDestroyWindow(Win);
  69       exit(1);
  70    default:
  71       return;
  72    }
  73    glutPostRedisplay();
  74 }
  75
  76 static void Draw(void)
  77 {
  78    printf("ColorMask = %d, %d, %d\n", Rmask, Gmask, Bmask);
  79    glColorMask(1,1,1,1);
  80
  81    glClear(GL_COLOR_BUFFER_BIT);
  82
  83    /* right triangle: green */
  84    glBegin(GL_TRIANGLES);
  85    glColor3f(0,1,0);
  86    glVertex3f( 0.9, -0.9, -30.0);
  87    glVertex3f( 0.9,  0.9, -30.0);
  88    glVertex3f(-0.9,  0.0, -30.0);
  89    glEnd();
  90
  91    glColorMask(Rmask, Gmask, Bmask, 0);
  92
  93    /* left triangle: white&mask: purple   middle region: white */
  94    glBegin(GL_TRIANGLES);
  95    glColor3f(1,1,1);
  96    glVertex3f(-0.9, -0.9, -30.0);
  97    glVertex3f(-0.9,  0.9, -30.0);
  98    glVertex3f( 0.9,  0.0, -30.0);
  99    glEnd();
 100
 101    glDisable(GL_SCISSOR_TEST);
 102
 103    glFlush();
 104
 105    if (doubleBuffer) {
 106       glutSwapBuffers();
 107    }
 108 }
 109
 110 static GLenum Args(int argc, char **argv)
 111 {
 112    GLint i;
 113
 114    doubleBuffer = GL_FALSE;
 115
 116    for (i = 1; i < argc; i++) {
 117       if (strcmp(argv[i], "-sb") == 0) {
 118          doubleBuffer = GL_FALSE;
 119       }
 120       else if (strcmp(argv[i], "-db") == 0) {
 121          doubleBuffer = GL_TRUE;
 122       }
 123       else {
 124          fprintf(stderr, "%s (Bad option).\n", argv[i]);
 125          return GL_FALSE;
 126       }
 127    }
 128    return GL_TRUE;
 129 }
 130
 131
 132 int main(int argc, char **argv)
 133 {
 134    GLenum type;
 135
 136    glutInit(&argc, argv);
 137
 138    if (Args(argc, argv) == GL_FALSE) {
 139       exit(1);
 140    }
 141
 142    type = GLUT_RGB;
 143    type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
 144
 145    glutInitWindowPosition(100, 0); glutInitWindowSize(Width, Height);
 146    glutInitDisplayMode(type);
 147    Win = glutCreateWindow(*argv);
 148    Init();
 149    glutReshapeFunc(Reshape);
 150    glutKeyboardFunc(Key);
 151    glutDisplayFunc(Draw);
 152    glutMainLoop();
 153    return 0;
 154 }