1/*
2 * (C) Copyright IBM Corporation 2005
3 * All Rights Reserved.
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * on the rights to use, copy, modify, merge, publish, distribute, sub
9 * license, and/or sell copies of the Software, and to permit persons to whom
10 * the Software is furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice (including the next
13 * paragraph) shall be included in all copies or substantial portions of the
14 * Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.  IN NO EVENT SHALL
19 * IBM AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
20 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
21 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
22 * USE OR OTHER DEALINGS IN THE SOFTWARE.
23 */
24
25
26#include <stdio.h>
27#include <stdlib.h>
28#include <string.h>
29#include <math.h>
30#include <GL/glew.h>
31#include "glut_wrap.h"
32
33const GLenum filter_modes[] = {
34     GL_NEAREST,
35     GL_LINEAR,
36     GL_NEAREST_MIPMAP_NEAREST,
37     GL_NEAREST_MIPMAP_LINEAR,
38     GL_LINEAR_MIPMAP_NEAREST,
39     GL_LINEAR_MIPMAP_LINEAR,
40};
41
42static GLenum min_filter = GL_LINEAR_MIPMAP_LINEAR;
43static GLenum mag_filter = GL_LINEAR;
44
45static unsigned segments = 64;
46static GLfloat * position_data = NULL;
47static GLfloat * texcoord_data = NULL;
48static GLfloat max_anisotropy = 0.0;
49static GLfloat anisotropy = 1.0;
50
51static void generate_tunnel( unsigned num_segs, GLfloat ** pos_data,
52    GLfloat ** tex_data );
53static void generate_textures( unsigned mode );
54
55#define min(a,b)  ( (a) < (b) ) ? (a) : (b)
56#define max(a,b)  ( (a) > (b) ) ? (a) : (b)
57
58
59static void Display( void )
60{
61   glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, min_filter );
62   glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, mag_filter );
63
64   if ( max_anisotropy > 0.0 ) {
65      glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT,
66		       anisotropy );
67   }
68
69   glClear( GL_COLOR_BUFFER_BIT );
70   glLoadIdentity();
71   glTranslatef( 0.0f, 0.0f, -19.0f );
72
73   glVertexPointer( 4, GL_FLOAT, 0, position_data );
74   glTexCoordPointer( 2, GL_FLOAT, 0, texcoord_data );
75   glEnableClientState( GL_VERTEX_ARRAY );
76   glEnableClientState( GL_TEXTURE_COORD_ARRAY );
77   glDrawArrays( GL_QUADS, 0, 4 * segments );
78   glutSwapBuffers();
79}
80
81
82static void Reshape( int width, int height )
83{
84   glViewport(0, 0, width, height);
85   glMatrixMode(GL_PROJECTION);
86   glLoadIdentity();
87   gluPerspective(45.0f, (GLfloat)(width)/(GLfloat)(height), 0.1f, 100.0f);
88   glMatrixMode(GL_MODELVIEW);
89   glLoadIdentity();
90}
91
92
93static void Key( unsigned char key, int x, int y )
94{
95   GLfloat new_anisotropy = anisotropy;
96
97   (void) x;
98   (void) y;
99
100
101   switch( key ) {
102   case 'a': {
103      new_anisotropy = anisotropy - 1.0;
104      break;
105   }
106
107   case 'A': {
108      new_anisotropy = anisotropy + 1.0;
109      break;
110   }
111
112   case 's': {
113      segments--;
114      if ( segments < 3 ) {
115	 segments = 3;
116      }
117      generate_tunnel( segments, & position_data, & texcoord_data );
118      break;
119   }
120
121   case 'S': {
122      segments++;
123      if ( segments > 128 ) {
124	 segments = 128;
125      }
126      generate_tunnel( segments, & position_data, & texcoord_data );
127      break;
128   }
129   case 'q':
130   case 'Q':
131   case 27:
132      exit(0);
133      break;
134   }
135
136   new_anisotropy = max( new_anisotropy, 1.0 );
137   new_anisotropy = min( new_anisotropy, max_anisotropy );
138   if ( new_anisotropy != anisotropy ) {
139      anisotropy = new_anisotropy;
140      printf( "Texture anisotropy: %f%s\n", anisotropy,
141	      (anisotropy == 1.0) ? " (disabled)" : "" );
142   }
143
144   glutPostRedisplay();
145}
146
147
148static void SpecialKey( int key, int x, int y )
149{
150   (void) x;
151   (void) y;
152   (void) key;
153   glutPostRedisplay();
154}
155
156
157static void menu_handler( int selection )
158{
159   switch( selection >> 3 ) {
160   case 0:
161      glBindTexture( GL_TEXTURE_2D, selection );
162      break;
163
164   case 1:
165      min_filter = filter_modes[ selection & 7 ];
166      break;
167
168   case 2:
169      mag_filter = filter_modes[ selection & 7 ];
170      break;
171   }
172
173   glutPostRedisplay();
174}
175
176
177static void Init( void )
178{
179   glDisable(GL_CULL_FACE);
180   glEnable(GL_TEXTURE_2D);
181   glClearColor(0.0f, 0.0f, 0.4f, 0.0f);
182   glShadeModel(GL_SMOOTH);
183   glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
184
185   generate_tunnel( segments, & position_data, & texcoord_data );
186
187   glBindTexture( GL_TEXTURE_2D, 1 );
188   generate_textures(1);
189
190   glBindTexture( GL_TEXTURE_2D, 2 );
191   generate_textures(2);
192
193   glBindTexture( GL_TEXTURE_2D, 3 );
194   generate_textures(3);
195
196   if ( glutExtensionSupported( "GL_EXT_texture_filter_anisotropic" ) ) {
197      glGetFloatv( GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT, & max_anisotropy );
198   }
199
200   printf("Maximum texture anisotropy: %f\n", max_anisotropy );
201
202   /* Create the menus. */
203
204   glutCreateMenu( menu_handler );
205   glutAddMenuEntry( "Min filter: GL_NEAREST",                 8 + 0 );
206   glutAddMenuEntry( "Min filter: GL_LINEAR",                  8 + 1 );
207   glutAddMenuEntry( "Min filter: GL_NEAREST_MIMMAP_NEAREST",  8 + 2 );
208   glutAddMenuEntry( "Min filter: GL_NEAREST_MIMMAP_LINEAR",   8 + 3 );
209   glutAddMenuEntry( "Min filter: GL_LINEAR_MIMMAP_NEAREST",   8 + 4 );
210   glutAddMenuEntry( "Min filter: GL_LINEAR_MIMMAP_LINEAR",    8 + 5 );
211   glutAddMenuEntry( "Mag filter: GL_NEAREST",                16 + 0 );
212   glutAddMenuEntry( "Mag filter: GL_LINEAR",                 16 + 1 );
213   glutAddMenuEntry( "Texture: regular mipmaps",                   1 );
214   glutAddMenuEntry( "Texture: blended mipmaps",                   2 );
215   glutAddMenuEntry( "Texture: color mipmaps",                     3 );
216   glutAttachMenu( GLUT_RIGHT_BUTTON );
217}
218
219
220static void generate_tunnel( unsigned num_segs, GLfloat ** pos_data,
221			     GLfloat ** tex_data )
222{
223   const GLfloat far_distance = 20.0f;
224   const GLfloat near_distance = -90.0f;
225   const GLfloat far_tex = 30.0f;
226   const GLfloat near_tex = 0.0f;
227   const GLfloat angle_step = (2 * M_PI) / num_segs;
228   const GLfloat tex_coord_step = 2.0 / num_segs;
229   GLfloat angle = 0.0f;
230   GLfloat tex_coord = 0.0f;
231   unsigned i;
232   GLfloat * position;
233   GLfloat * texture;
234
235
236   position = realloc( *pos_data, sizeof( GLfloat ) * num_segs * 4 * 4 );
237   texture = realloc( *tex_data, sizeof( GLfloat ) * num_segs * 4 * 2 );
238
239   *pos_data = position;
240   *tex_data = texture;
241
242   for ( i = 0 ; i < num_segs ; i++ ) {
243      position[0] = 2.5 * sinf( angle );
244      position[1] = 2.5 * cosf( angle );
245      position[2] = (i & 1) ? far_distance : near_distance;
246      position[3] = 1.0f;
247
248      position[4] = position[0];
249      position[5] = position[1];
250      position[6] = (i & 1) ? near_distance : far_distance;
251      position[7] = 1.0f;
252
253      position += 8;
254
255      texture[0] = tex_coord;
256      texture[1] = (i & 1) ? far_tex : near_tex;
257      texture += 2;
258
259      texture[0] = tex_coord;
260      texture[1] = (i & 1) ? near_tex : far_tex;
261      texture += 2;
262
263      angle += angle_step;
264      tex_coord += tex_coord_step;
265
266      position[0] = 2.5 * sinf( angle );
267      position[1] = 2.5 * cosf( angle );
268      position[2] = (i & 1) ? near_distance : far_distance;
269      position[3] = 1.0f;
270
271      position[4] = position[0];
272      position[5] = position[1];
273      position[6] = (i & 1) ? far_distance : near_distance;
274      position[7] = 1.0f;
275
276      position += 8;
277
278      texture[0] = tex_coord;
279      texture[1] = (i & 1) ? near_tex : far_tex;
280      texture += 2;
281
282      texture[0] = tex_coord;
283      texture[1] = (i & 1) ? far_tex : near_tex;
284      texture += 2;
285   }
286}
287
288
289static void generate_textures( unsigned mode )
290{
291#define LEVEL_COLORS 6
292   const GLfloat colors[LEVEL_COLORS][3] = {
293	{ 1.0, 0.0, 0.0 },  /* 32 x 32 */
294	{ 0.0, 1.0, 0.0 },  /* 16 x 16 */
295	{ 0.0, 0.0, 1.0 },  /*  8 x  8 */
296	{ 1.0, 0.0, 1.0 },  /*  4 x  4 */
297	{ 1.0, 1.0, 1.0 },  /*  2 x  2 */
298	{ 1.0, 1.0, 0.0 }   /*  1 x  1 */
299   };
300   const unsigned checkers_per_level = 2;
301   GLfloat * tex;
302   unsigned level;
303   unsigned size;
304   GLint max_size;
305
306
307   glGetIntegerv( GL_MAX_TEXTURE_SIZE, & max_size );
308   if ( max_size > 512 ) {
309      max_size = 512;
310   }
311
312   tex = malloc( sizeof( GLfloat ) * 3 * max_size * max_size );
313
314   level = 0;
315   for ( size = max_size ; size > 0 ; size >>= 1 ) {
316      unsigned divisor = size / checkers_per_level;
317      unsigned i;
318      unsigned j;
319      GLfloat checkers[2][3];
320
321
322      if ((level == 0) || (mode == 1)) {
323	 checkers[0][0] = 1.0;
324	 checkers[0][1] = 1.0;
325	 checkers[0][2] = 1.0;
326	 checkers[1][0] = 0.0;
327	 checkers[1][1] = 0.0;
328	 checkers[1][2] = 0.0;
329      }
330      else if (mode == 2) {
331	 checkers[0][0] = colors[level % LEVEL_COLORS][0];
332	 checkers[0][1] = colors[level % LEVEL_COLORS][1];
333	 checkers[0][2] = colors[level % LEVEL_COLORS][2];
334	 checkers[1][0] = colors[level % LEVEL_COLORS][0] * 0.5;
335	 checkers[1][1] = colors[level % LEVEL_COLORS][1] * 0.5;
336	 checkers[1][2] = colors[level % LEVEL_COLORS][2] * 0.5;
337      }
338      else {
339	 checkers[0][0] = colors[level % LEVEL_COLORS][0];
340	 checkers[0][1] = colors[level % LEVEL_COLORS][1];
341	 checkers[0][2] = colors[level % LEVEL_COLORS][2];
342	 checkers[1][0] = colors[level % LEVEL_COLORS][0];
343	 checkers[1][1] = colors[level % LEVEL_COLORS][1];
344	 checkers[1][2] = colors[level % LEVEL_COLORS][2];
345      }
346
347      if ( divisor == 0 ) {
348	 divisor = 1;
349
350	 checkers[0][0] = (checkers[0][0] + checkers[1][0]) / 2;
351	 checkers[0][1] = (checkers[0][0] + checkers[1][0]) / 2;
352	 checkers[0][2] = (checkers[0][0] + checkers[1][0]) / 2;
353	 checkers[1][0] = checkers[0][0];
354	 checkers[1][1] = checkers[0][1];
355	 checkers[1][2] = checkers[0][2];
356      }
357
358
359      for ( i = 0 ; i < size ; i++ ) {
360	 for ( j = 0 ; j < size ; j++ ) {
361	    const unsigned idx = ((i ^ j) / divisor) & 1;
362
363	    tex[ ((i * size) + j) * 3 + 0] = checkers[ idx ][0];
364	    tex[ ((i * size) + j) * 3 + 1] = checkers[ idx ][1];
365	    tex[ ((i * size) + j) * 3 + 2] = checkers[ idx ][2];
366	 }
367      }
368
369      glTexImage2D( GL_TEXTURE_2D, level, GL_RGB, size, size, 0,
370		    GL_RGB, GL_FLOAT, tex );
371      level++;
372   }
373
374   free( tex );
375}
376
377
378int main( int argc, char ** argv )
379{
380   glutInit( &argc, argv );
381   glutInitWindowPosition( 0, 0 );
382   glutInitWindowSize( 800, 600 );
383   glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
384   glutCreateWindow( "Texture Filter Test" );
385   glewInit();
386   glutReshapeFunc( Reshape );
387   glutKeyboardFunc( Key );
388   glutSpecialFunc( SpecialKey );
389   glutDisplayFunc( Display );
390
391   Init();
392
393   printf("\nUse the right-button menu to select the texture and filter mode.\n");
394   printf("Use 'A' and 'a' to increase and decrease the aniotropy.\n");
395   printf("Use 'S' and 's' to increase and decrease the number of cylinder segments.\n");
396   printf("Use 'q' to exit.\n\n");
397
398   glutMainLoop();
399   return 0;
400}
401