mipgen.c revision 32001f49 
1/* Test GL_TEXTURE_BASE_LEVEL and GL_TEXTURE_MAX_LEVEL
2 * Brian Paul
3 * 10 May 2006
4 */
5
6
7/* Copyright (c) Mark J. Kilgard, 1994. */
8
9/*
10 * (c) Copyright 1993, Silicon Graphics, Inc.
11 * ALL RIGHTS RESERVED
12 * Permission to use, copy, modify, and distribute this software for
13 * any purpose and without fee is hereby granted, provided that the above
14 * copyright notice appear in all copies and that both the copyright notice
15 * and this permission notice appear in supporting documentation, and that
16 * the name of Silicon Graphics, Inc. not be used in advertising
17 * or publicity pertaining to distribution of the software without specific,
18 * written prior permission.
19 *
20 * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
21 * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
22 * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
23 * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
24 * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
25 * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
26 * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
27 * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
28 * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN
29 * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
30 * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
31 * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
32 *
33 * US Government Users Restricted Rights
34 * Use, duplication, or disclosure by the Government is subject to
35 * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
36 * (c)(1)(ii) of the Rights in Technical Data and Computer Software
37 * clause at DFARS 252.227-7013 and/or in similar or successor
38 * clauses in the FAR or the DOD or NASA FAR Supplement.
39 * Unpublished-- rights reserved under the copyright laws of the
40 * United States.  Contractor/manufacturer is Silicon Graphics,
41 * Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311.
42 *
43 * OpenGL(TM) is a trademark of Silicon Graphics, Inc.
44 */
45
46#include <stdlib.h>
47#include <stdio.h>
48#include <GL/glew.h>
49#include "glut_wrap.h"
50
51
52static GLfloat LodBias = 6.0;   /* make smallest miplevel visible */
53static GLuint texImage;
54
55#define WIDTH 2
56#define HEIGHT 2
57
58static void
59InitValues(void)
60{
61   LodBias = 6.0;               /* make smallest miplevel visible */
62}
63
64
65static void MakeImage(void)
66{
67   const GLubyte color0[4] = { 0xff, 0x80, 0x20, 0xff };
68   const GLubyte color1[4] = { 0x10, 0x20, 0x40, 0xff };
69
70   GLubyte img[WIDTH*HEIGHT*3];
71   int i, j;
72   for (i = 0; i < HEIGHT; i++) {
73      for (j = 0; j < WIDTH; j++) {
74         int k = (i * WIDTH + j) * 3;
75         int p = ((i+j)%2);
76         if (p == 0) {
77            img[k + 0] = color0[0];
78            img[k + 1] = color0[1];
79            img[k + 2] = color0[2];
80         }
81         else {
82            img[k + 0] = color1[0];
83            img[k + 1] = color1[1];
84            img[k + 2] = color1[2];
85         }
86      }
87   }
88
89   glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP_SGIS, GL_TRUE);
90   glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, WIDTH, HEIGHT, 0,
91                GL_RGB, GL_UNSIGNED_BYTE, img);
92   glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP_SGIS, GL_FALSE);
93}
94
95
96
97static void myinit(void)
98{
99   InitValues();
100
101   glShadeModel(GL_FLAT);
102
103   glTranslatef(0.0, 0.0, -3.6);
104
105   glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
106   glGenTextures(1, &texImage);
107   glBindTexture(GL_TEXTURE_2D, texImage);
108   MakeImage();
109
110   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
111   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
112   glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
113   glEnable(GL_TEXTURE_2D);
114
115   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);
116   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 1);
117
118   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_LOD, -1);
119   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAX_LOD, 1);
120
121   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
122   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
123                   GL_NEAREST_MIPMAP_NEAREST);
124}
125
126
127
128static void display(void)
129{
130   GLfloat tcm = 1.0;
131   glBindTexture(GL_TEXTURE_2D, texImage);
132
133   printf("Bias=%.2g\n", LodBias);
134   fflush(stdout);
135
136   glTexEnvf(GL_TEXTURE_FILTER_CONTROL_EXT, GL_TEXTURE_LOD_BIAS_EXT, LodBias);
137
138   glClear(GL_COLOR_BUFFER_BIT);
139   glBegin(GL_QUADS);
140   glTexCoord2f(0.0, 0.0); glVertex3f(-2.0, -1.0, 0.0);
141   glTexCoord2f(0.0, tcm); glVertex3f(-2.0, 1.0, 0.0);
142   glTexCoord2f(tcm * 3000.0, tcm); glVertex3f(3000.0, 1.0, -6000.0);
143   glTexCoord2f(tcm * 3000.0, 0.0); glVertex3f(3000.0, -1.0, -6000.0);
144   glEnd();
145   glFlush();
146}
147
148static void myReshape(int w, int h)
149{
150   glViewport(0, 0, w, h);
151   glMatrixMode(GL_PROJECTION);
152   glLoadIdentity();
153   gluPerspective(60.0, 1.0*(GLfloat)w/(GLfloat)h, 1.0, 30000.0);
154   glMatrixMode(GL_MODELVIEW);
155   glLoadIdentity();
156}
157
158static void
159key(unsigned char k, int x, int y)
160{
161  (void) x;
162  (void) y;
163  switch (k) {
164  case 'l':
165     LodBias -= 0.25;
166     break;
167  case 'L':
168     LodBias += 0.25;
169     break;
170  case ' ':
171     InitValues();
172     break;
173  case 27:  /* Escape */
174    exit(0);
175    break;
176  default:
177    return;
178  }
179  glutPostRedisplay();
180}
181
182
183static void usage(void)
184{
185   printf("usage:\n");
186   printf("  l/L    decrease/increase GL_TEXTURE_LOD_BIAS\n");
187   printf("  SPACE  reset values\n");
188}
189
190
191int main(int argc, char** argv)
192{
193    glutInit(&argc, argv);
194    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB );
195    glutInitWindowSize (600, 600);
196    glutCreateWindow (argv[0]);
197    glewInit();
198    myinit();
199    glutReshapeFunc (myReshape);
200    glutDisplayFunc(display);
201    glutKeyboardFunc(key);
202    usage();
203    glutMainLoop();
204    return 0;             /* ANSI C requires main to return int. */
205}
206