3 * Specular reflection demo. The specular highlight is modulated by
4 * a sphere-mapped texture. The result is a high-gloss surface.
5 * NOTE: you really need hardware acceleration for this.
6 * Also note, this technique can't be implemented with multi-texture
7 * and separate specular color interpolation because there's no way
8 * to indicate that the second texture unit (the reflection map)
9 * should modulate the specular color and not the base color.
10 * A future multi-texture extension could fix that.
12 * Command line options:
13 * -info print GL implementation information
16 * Brian Paul October 22, 1999 This program is in the public domain.
29 #include "trackball.h"
32 #define SPECULAR_TEXTURE_FILE "../images/reflect.rgb"
33 #define BASE_TEXTURE_FILE "../images/tile.rgb"
36 #define DO_SPEC_TEXTURE 1
44 static GLint WinWidth = 500, WinHeight = 500;
45 static GLuint CylinderObj = 0;
46 static GLuint TeapotObj = 0;
47 static GLuint Object = 0;
48 static GLboolean Animate = GL_TRUE;
50 static float CurQuat[4] = { 0, 0, 0, 1 };
52 static GLfloat Black[4] = { 0, 0, 0, 0 };
53 static GLfloat White[4] = { 1, 1, 1, 1 };
54 static GLfloat Diffuse[4] = { .3, .3, 1.0, 1.0 }; /* blue */
55 static GLfloat Shininess = 6;
57 static GLuint BaseTexture, SpecularTexture;
58 static GLboolean DoSpecTexture = GL_TRUE;
60 static GLboolean ButtonDown = GL_FALSE;
61 static GLint ButtonX, ButtonY;
64 /* performance info */
66 static GLint Frames = 0;
69 static void Idle( void )
71 static const float yAxis[3] = {0, 1, 0};
72 static double t0 = -1.;
74 double dt, t = glutGet(GLUT_ELAPSED_TIME) / 1000.0;
80 axis_to_quat(yAxis, 2.0 * dt, quat);
81 add_quats(quat, CurQuat, CurQuat);
87 static void Display( void )
91 glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
94 build_rotmatrix(rot, CurQuat);
95 glMultMatrixf(&rot[0][0]);
97 /* First pass: diffuse lighting with base texture */
98 glMaterialfv(GL_FRONT, GL_DIFFUSE, Diffuse);
99 glMaterialfv(GL_FRONT, GL_SPECULAR, Black);
100 glEnable(GL_TEXTURE_2D);
101 glBindTexture(GL_TEXTURE_2D, BaseTexture);
104 /* Second pass: specular lighting with reflection texture */
105 glEnable(GL_POLYGON_OFFSET_FILL);
106 glBlendFunc(GL_ONE, GL_ONE); /* add */
108 glMaterialfv(GL_FRONT, GL_DIFFUSE, Black);
109 glMaterialfv(GL_FRONT, GL_SPECULAR, White);
111 glBindTexture(GL_TEXTURE_2D, SpecularTexture);
112 glEnable(GL_TEXTURE_GEN_S);
113 glEnable(GL_TEXTURE_GEN_T);
116 glDisable(GL_TEXTURE_2D);
119 glDisable(GL_TEXTURE_GEN_S);
120 glDisable(GL_TEXTURE_GEN_T);
122 glDisable(GL_POLYGON_OFFSET_FILL);
129 GLint t = glutGet(GLUT_ELAPSED_TIME);
131 if (t - T0 >= 5000) {
132 GLfloat seconds = (t - T0) / 1000.0;
133 GLfloat fps = Frames / seconds;
134 printf("%d frames in %g seconds = %g FPS\n", Frames, seconds, fps);
142 static void Reshape( int width, int height )
145 GLfloat w = h * width / height;
148 glViewport( 0, 0, width, height );
149 glMatrixMode( GL_PROJECTION );
151 glFrustum( -w, w, -h, h, 150.0, 500.0 );
152 glMatrixMode( GL_MODELVIEW );
154 glTranslatef( 0.0, 0.0, -380.0 );
158 static void ToggleAnimate(void)
162 glutIdleFunc( Idle );
163 T0 = glutGet(GLUT_ELAPSED_TIME);
167 glutIdleFunc( NULL );
172 static void ModeMenu(int entry)
174 if (entry==ANIMATE) {
177 else if (entry==DO_SPEC_TEXTURE) {
178 DoSpecTexture = !DoSpecTexture;
180 else if (entry==OBJECT) {
181 if (Object == TeapotObj)
182 Object = CylinderObj;
186 else if (entry==QUIT) {
193 static void Key( unsigned char key, int x, int y )
202 glMaterialf(GL_FRONT, GL_SHININESS, Shininess);
203 printf("Shininess = %g\n", Shininess);
207 if (Shininess > 128.0)
209 glMaterialf(GL_FRONT, GL_SHININESS, Shininess);
210 printf("Shininess = %g\n", Shininess);
225 MouseMotion(int x, int y)
228 float x0 = (2.0 * ButtonX - WinWidth) / WinWidth;
229 float y0 = (WinHeight - 2.0 * ButtonY) / WinHeight;
230 float x1 = (2.0 * x - WinWidth) / WinWidth;
231 float y1 = (WinHeight - 2.0 * y) / WinHeight;
234 trackball(q, x0, y0, x1, y1);
237 add_quats(q, CurQuat, CurQuat);
245 MouseButton(int button, int state, int x, int y)
247 if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) {
248 ButtonDown = GL_TRUE;
252 else if (button == GLUT_LEFT_BUTTON && state == GLUT_UP) {
253 ButtonDown = GL_FALSE;
258 static void Init( int argc, char *argv[] )
260 GLboolean convolve = GL_FALSE;
261 GLboolean fullscreen = GL_FALSE;
264 for (i = 1; i < argc; i++) {
265 if (strcmp(argv[i], "-info")==0) {
266 printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
267 printf("GL_VERSION = %s\n", (char *) glGetString(GL_VERSION));
268 printf("GL_VENDOR = %s\n", (char *) glGetString(GL_VENDOR));
269 printf("GL_EXTENSIONS = %s\n", (char *) glGetString(GL_EXTENSIONS));
271 else if (strcmp(argv[i], "-c")==0) {
274 else if (strcmp(argv[i], "-f")==0) {
275 fullscreen = GL_TRUE;
282 /* Cylinder object */
284 static GLfloat height = 100.0;
285 static GLfloat radius = 40.0;
286 static GLint slices = 24; /* pie slices around Z axis */
287 static GLint stacks = 10; /* subdivisions along length of cylinder */
288 static GLint rings = 4; /* rings in the end disks */
289 GLUquadricObj *q = gluNewQuadric();
291 gluQuadricTexture(q, GL_TRUE);
293 CylinderObj = glGenLists(1);
294 glNewList(CylinderObj, GL_COMPILE);
297 glTranslatef(0.0, 0.0, -0.5 * height);
299 glMatrixMode(GL_TEXTURE);
301 /*glScalef(8.0, 4.0, 2.0);*/
302 glMatrixMode(GL_MODELVIEW);
305 gluQuadricNormals(q, GL_SMOOTH);
306 gluQuadricTexture(q, GL_TRUE);
307 gluCylinder(q, radius, radius, height, slices, stacks);
310 glMatrixMode(GL_TEXTURE);
312 glScalef(3.0, 3.0, 1.0);
313 glMatrixMode(GL_MODELVIEW);
315 glTranslatef(0.0, 0.0, height);
316 gluDisk(q, 0.0, radius, slices, rings);
319 glTranslatef(0.0, 0.0, -height);
320 gluQuadricOrientation(q, GLU_INSIDE);
321 gluDisk(q, 0.0, radius, slices, rings);
325 glMatrixMode(GL_TEXTURE);
327 glMatrixMode(GL_MODELVIEW);
335 TeapotObj = glGenLists(1);
336 glNewList(TeapotObj, GL_COMPILE);
339 glutSolidTeapot(40.0);
345 /* show cylinder by default */
346 Object = CylinderObj;
350 glEnable(GL_LIGHTING);
352 GLfloat pos[4] = { 3, 3, 3, 1 };
353 glLightfv(GL_LIGHT0, GL_AMBIENT, Black);
354 glLightfv(GL_LIGHT0, GL_DIFFUSE, White);
355 glLightfv(GL_LIGHT0, GL_SPECULAR, White);
356 glLightfv(GL_LIGHT0, GL_POSITION, pos);
358 glMaterialfv(GL_FRONT, GL_AMBIENT, Black);
359 glMaterialf(GL_FRONT, GL_SHININESS, Shininess);
360 glLightModeli(GL_LIGHT_MODEL_LOCAL_VIEWER, 1);
364 glGenTextures(1, &BaseTexture);
365 glBindTexture(GL_TEXTURE_2D, BaseTexture);
366 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
367 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
368 if (!LoadRGBMipmaps(BASE_TEXTURE_FILE, GL_RGB)) {
369 printf("Error: couldn't load texture image file %s\n", BASE_TEXTURE_FILE);
373 /* Specular texture */
374 glGenTextures(1, &SpecularTexture);
375 glBindTexture(GL_TEXTURE_2D, SpecularTexture);
376 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
377 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
378 glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_SPHERE_MAP);
379 glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_SPHERE_MAP);
381 /* use convolution to blur the texture to simulate a dull finish
387 GLfloat filter[FILTER_SIZE][FILTER_SIZE][4];
389 for (h = 0; h < FILTER_SIZE; h++) {
390 for (w = 0; w < FILTER_SIZE; w++) {
391 const GLfloat k = 1.0 / (FILTER_SIZE * FILTER_SIZE);
399 glEnable(GL_CONVOLUTION_2D);
400 glConvolutionParameteri(GL_CONVOLUTION_2D,
401 GL_CONVOLUTION_BORDER_MODE, GL_CONSTANT_BORDER);
402 glConvolutionFilter2D(GL_CONVOLUTION_2D, GL_RGBA,
403 FILTER_SIZE, FILTER_SIZE,
404 GL_RGBA, GL_FLOAT, filter);
406 img = LoadRGBImage(SPECULAR_TEXTURE_FILE, &w, &h, &format);
408 printf("Error: couldn't load texture image file %s\n",
409 SPECULAR_TEXTURE_FILE);
413 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, w, h, 0,
414 format, GL_UNSIGNED_BYTE, img);
419 if (!LoadRGBMipmaps(SPECULAR_TEXTURE_FILE, GL_RGB)) {
420 printf("Error: couldn't load texture image file %s\n",
421 SPECULAR_TEXTURE_FILE);
427 glEnable(GL_CULL_FACE);
428 glEnable(GL_TEXTURE_2D);
429 glEnable(GL_DEPTH_TEST);
430 glEnable(GL_NORMALIZE);
432 glPolygonOffset( -1, -1 );
436 int main( int argc, char *argv[] )
438 glutInit( &argc, argv );
439 glutInitWindowSize(WinWidth, WinHeight);
440 glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH );
441 glutCreateWindow(argv[0] );
443 glutReshapeFunc( Reshape );
444 glutKeyboardFunc( Key );
445 glutDisplayFunc( Display );
446 glutMotionFunc(MouseMotion);
447 glutMouseFunc(MouseButton);
449 glutIdleFunc( Idle );
451 glutCreateMenu(ModeMenu);
452 glutAddMenuEntry("Toggle Highlight", DO_SPEC_TEXTURE);
453 glutAddMenuEntry("Toggle Object", OBJECT);
454 glutAddMenuEntry("Toggle Animate", ANIMATE);
455 glutAddMenuEntry("Quit", QUIT);
456 glutAttachMenu(GLUT_RIGHT_BUTTON);