scissor.c revision 32001f49 
1/*
2 * Copyright (c) 1991, 1992, 1993 Silicon Graphics, Inc.
3 * Copyright (c) 2009 VMware, Inc.
4 *
5 * Permission to use, copy, modify, distribute, and sell this software and
6 * its documentation for any purpose is hereby granted without fee, provided
7 * that (i) the above copyright notices and this permission notice appear in
8 * all copies of the software and related documentation, and (ii) the name of
9 * Silicon Graphics may not be used in any advertising or
10 * publicity relating to the software without the specific, prior written
11 * permission of Silicon Graphics.
12 *
13 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF
14 * ANY KIND,
15 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
16 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
17 *
18 * IN NO EVENT SHALL SILICON GRAPHICS BE LIABLE FOR
19 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
20 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
21 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
22 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
23 * OF THIS SOFTWARE.
24 */
25
26#include <stdio.h>
27#include <string.h>
28#include <stdlib.h>
29#include "glut_wrap.h"
30
31struct program
32{
33   unsigned width;
34   unsigned height;
35   unsigned quads;
36};
37
38struct program prog;
39
40static void init(void)
41{
42   fprintf(stderr, "GL_RENDERER   = %s\n", (char *) glGetString(GL_RENDERER));
43   fprintf(stderr, "GL_VERSION    = %s\n", (char *) glGetString(GL_VERSION));
44   fprintf(stderr, "GL_VENDOR     = %s\n", (char *) glGetString(GL_VENDOR));
45   fflush(stderr);
46}
47
48static void reshape(int width, int height)
49{
50
51   glViewport(0, 0, (GLint)width, (GLint)height);
52
53   prog.width = width;
54   prog.height = height;
55
56   glMatrixMode(GL_PROJECTION);
57   glLoadIdentity();
58   glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
59   glMatrixMode(GL_MODELVIEW);
60}
61
62static void key(unsigned char key, int x, int y)
63{
64
65   switch (key) {
66   case 27:
67      exit(1);
68   default:
69      prog.quads = !prog.quads;
70      glutPostRedisplay();
71      return;
72   }
73}
74
75static void drawQuad(void)
76{
77
78   if (prog.quads) {
79      glBegin(GL_QUADS);
80      glVertex2d(-1.0, -1.0);
81      glVertex2d( 1.0, -1.0);
82      glVertex2d( 1.0,  1.0);
83      glVertex2d(-1.0,  1.0);
84      glEnd();
85   } else {
86      glClear(GL_COLOR_BUFFER_BIT);
87   }
88}
89
90static void draw(void)
91{
92   glClearColor(0.0, 0.0, 1.0, 0.0);
93   glClear(GL_COLOR_BUFFER_BIT);
94
95   printf("drawing with %s\n", prog.quads ? "quads" : "clears");
96
97   glEnable(GL_SCISSOR_TEST);
98
99   {
100      glClearColor(1.0, 0.0, 0.0, 1.0);
101      glColor4d(1.0, 0.0, 0.0, 1.0);
102
103      glScissor(1, 1, 10, 10);
104      drawQuad();
105      glScissor(1, prog.height -  11, 10, 10);
106      drawQuad();
107      glScissor(prog.width - 11, prog.height -  11, 10, 10);
108      drawQuad();
109   }
110
111   {
112      glClearColor(0.0, 1.0, 0.0, 1.0);
113      glColor4d(0.0, 1.0, 0.0, 1.0);
114
115      glScissor(12, 1, 10, 10);
116      drawQuad();
117      glScissor(12, prog.height -  11, 10, 10);
118      drawQuad();
119      glScissor(prog.width - 22, prog.height -  11, 10, 10);
120      drawQuad();
121   }
122
123   {
124      glClearColor(1.0, 1.0, 0.0, 1.0);
125      glColor4d(1.0, 1.0, 0.0, 1.0);
126
127      glScissor(1, 12, 10, 10);
128      drawQuad();
129      glScissor(1, prog.height -  22, 10, 10);
130      drawQuad();
131      glScissor(prog.width - 11, prog.height -  22, 10, 10);
132      drawQuad();
133   }
134
135   glDisable(GL_SCISSOR_TEST);
136
137   /* glutSwapBuffers(); */
138   glFlush();
139}
140
141int main(int argc, char **argv)
142{
143   GLenum type;
144
145   glutInit(&argc, argv);
146
147   prog.width = 200;
148   prog.height = 200;
149
150   glutInitWindowPosition(100, 0);
151   glutInitWindowSize(prog.width, prog.height);
152
153   /* type = GLUT_RGB | GLUT_DOUBLE; */
154   type = GLUT_RGB | GLUT_SINGLE;
155   glutInitDisplayMode(type);
156
157   if (glutCreateWindow(*argv) == GL_FALSE) {
158      exit(1);
159   }
160
161   init();
162
163   glutReshapeFunc(reshape);
164   glutKeyboardFunc(key);
165   glutDisplayFunc(draw);
166   glutMainLoop();
167   return 0;
168}
169