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/* Test GL_TEXTURE_BASE_LEVEL and GL_TEXTURE_MAX_LEVEL
* Brian Paul
* 10 May 2006
*/
/* Copyright (c) Mark J. Kilgard, 1994. */
/*
* (c) Copyright 1993, 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* Unpublished-- rights reserved under the copyright laws of the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(TM) is a trademark of Silicon Graphics, Inc.
*/
/* mipmap.c
* This program demonstrates using mipmaps for texture maps.
* To overtly show the effect of mipmaps, each mipmap reduction
* level has a solidly colored, contrasting texture image.
* Thus, the quadrilateral which is drawn is drawn with several
* different colors.
*/
#include <stdlib.h>
#include <stdio.h>
#include <GL/glut.h>
static GLint BaseLevel = 0, MaxLevel = 8;
static GLfloat LodBias = 0.0;
static GLboolean NearestFilter = GL_TRUE;
static void MakeImage(int level, int width, int height, const GLubyte color[4])
{
const int makeStripes = 0;
GLubyte img[256*256*3];
int i, j;
for (i = 0; i < height; i++) {
for (j = 0; j < width; j++) {
int k = (i * width + j) * 3;
int p = (i/8) & makeStripes;
if (p == 0) {
img[k + 0] = color[0];
img[k + 1] = color[1];
img[k + 2] = color[2];
}
else {
img[k + 0] = 0;
img[k + 1] = 0;
img[k + 2] = 0;
}
}
}
glTexImage2D(GL_TEXTURE_2D, level, GL_RGB, width, height, 0,
GL_RGB, GL_UNSIGNED_BYTE, img);
}
static void makeImages(void)
{
static const GLubyte colors[8][3] = {
{128, 128, 128 },
{ 0, 255, 255 },
{ 255, 255, 0 },
{ 255, 0, 255 },
{ 255, 0, 0 },
{ 0, 255, 0 },
{ 0, 0, 255 },
{ 255, 255, 255 }
};
int i, sz = 128;
for (i = 0; i < 8; i++) {
MakeImage(i, sz, sz, colors[i]);
sz /= 2;
}
}
static void myinit(void)
{
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LESS);
glShadeModel(GL_FLAT);
glTranslatef(0.0, 0.0, -3.6);
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
makeImages();
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
glEnable(GL_TEXTURE_2D);
}
static void display(void)
{
GLfloat tcm = 4.0;
printf("GL_TEXTURE_BASE_LEVEL = %d GL_TEXTURE_MAX_LEVEL = %d Bias = %.2g filter = %s\n",
BaseLevel, MaxLevel, LodBias,
NearestFilter ? "LINEAR" : "NEAREST");
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, BaseLevel);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, MaxLevel);
if (NearestFilter) {
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
GL_NEAREST_MIPMAP_NEAREST);
}
else {
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
GL_LINEAR_MIPMAP_LINEAR);
}
glTexEnvf(GL_TEXTURE_FILTER_CONTROL_EXT, GL_TEXTURE_LOD_BIAS_EXT, LodBias);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glBegin(GL_QUADS);
glTexCoord2f(0.0, 0.0); glVertex3f(-2.0, -1.0, 0.0);
glTexCoord2f(0.0, tcm); glVertex3f(-2.0, 1.0, 0.0);
glTexCoord2f(tcm, tcm); glVertex3f(3000.0, 1.0, -6000.0);
glTexCoord2f(tcm, 0.0); glVertex3f(3000.0, -1.0, -6000.0);
glEnd();
glFlush();
}
static void myReshape(int w, int h)
{
glViewport(0, 0, w, h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(60.0, 1.0*(GLfloat)w/(GLfloat)h, 1.0, 30000.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
static void
key(unsigned char k, int x, int y)
{
(void) x;
(void) y;
switch (k) {
case 'b':
BaseLevel--;
if (BaseLevel < 0)
BaseLevel = 0;
break;
case 'B':
BaseLevel++;
if (BaseLevel > 10)
BaseLevel = 10;
break;
case 'm':
MaxLevel--;
if (MaxLevel < 0)
MaxLevel = 0;
break;
case 'M':
MaxLevel++;
if (MaxLevel > 10)
MaxLevel = 10;
break;
case 'l':
LodBias -= 0.02;
break;
case 'L':
LodBias += 0.02;
break;
case 'f':
NearestFilter = !NearestFilter;
break;
case 27: /* Escape */
exit(0);
break;
default:
return;
}
glutPostRedisplay();
}
static void usage(void)
{
printf("usage:\n");
printf(" b/B decrease/increase GL_TEXTURE_BASE_LEVEL\n");
printf(" m/M decrease/increase GL_TEXTURE_MAX_LEVEL\n");
printf(" f toggle nearest/linear filtering\n");
}
int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize (600, 600);
glutCreateWindow (argv[0]);
myinit();
glutReshapeFunc (myReshape);
glutDisplayFunc(display);
glutKeyboardFunc(key);
usage();
glutMainLoop();
return 0; /* ANSI C requires main to return int. */
}
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