Revert back to new tessellator, check version string to be sure we're

running with a valid GLU library.

progs/demos/tessdemo.c

-/* $Id: tessdemo.c,v 1.8 2000/07/11 14:11:58 brianp Exp $ */
+/* $Id: tessdemo.c,v 1.9 2001/03/21 02:43:14 gareth Exp $ */
 
 /*
  * A demo of the GLU polygon tesselation functions written by Bogdan Sikorski.
+ * Updated for GLU 1.3 tessellation by Gareth Hughes <gareth@valinux.com>
  */
 
-
 #include <GL/glut.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
-#define MAX_POINTS 200
-#define MAX_CONTOURS 50
+#define MAX_POINTS	256
+#define MAX_CONTOURS	32
+#define MAX_TRIANGLES	256
 
-static int menu;
-typedef enum
-{ QUIT, TESSELATE, CLEAR }
-menu_entries;
+#ifndef GLCALLBACK
+#ifdef CALLBACK
+#define GLCALLBACK CALLBACK
+#else
+#define GLCALLBACK
+#endif
+#endif
 
-typedef enum
-{ DEFINE, TESSELATED }
-mode_type;
+#ifdef GLU_VERSION_1_2
 
-struct
-{
-   GLint p[MAX_POINTS][2];
-   GLuint point_cnt;
-}
-contours[MAX_CONTOURS];
+typedef enum{ QUIT, TESSELATE, CLEAR } menu_entries;
+typedef enum{ DEFINE, TESSELATED } mode_type;
 
-static GLuint contour_cnt;
-static GLsizei width, height;
-static mode_type mode;
+static GLsizei		width, height;
+static GLuint		contour_cnt;
+static GLuint		triangle_cnt;
 
-struct
-{
-   GLsizei no;
-   GLfloat color[3];
-   GLint p[3][2];
-   GLclampf p_color[3][3];
-}
-triangle;
+static mode_type 	mode;
+static int		menu;
 
+static GLuint		list_start;
 
-static void GLCALLBACK
-my_error(GLenum err)
-{
-   int len, i;
-   char const *str;
-
-   glColor3f(0.9, 0.9, 0.9);
-   glRasterPos2i(5, 5);
-   str = (const char *) gluErrorString(err);
-   len = strlen(str);
-   for (i = 0; i < len; i++)
-      glutBitmapCharacter(GLUT_BITMAP_9_BY_15, str[i]);
-}
+static GLfloat		edge_color[3];
 
+static struct {
+   GLfloat	p[MAX_POINTS][2];
+   GLuint	point_cnt;
+} contours[MAX_CONTOURS];
 
-static void GLCALLBACK
-begin_callback(GLenum mode)
+static struct {
+   GLsizei	no;
+   GLfloat	p[3][2];
+   GLclampf	color[3][3];
+} triangles[MAX_TRIANGLES];
+
+
+
+static void GLCALLBACK error_callback( GLenum err )
 {
-   triangle.no = 0;
+   int		len, i;
+   char const	*str;
+
+   glColor3f( 0.9, 0.9, 0.9 );
+   glRasterPos2i( 5, 5 );
+
+   str = (const char *) gluErrorString( err );
+   len = strlen( str );
+
+   for ( i = 0 ; i < len ; i++ ) {
+      glutBitmapCharacter( GLUT_BITMAP_9_BY_15, str[i] );
+   }
 }
 
+static void GLCALLBACK begin_callback( GLenum mode )
+{
+   /* Allow multiple triangles to be output inside the begin/end pair. */
+   triangle_cnt = 0;
+   triangles[triangle_cnt].no = 0;
+}
 
-static void GLCALLBACK
-edge_callback(GLenum flag)
+static void GLCALLBACK edge_callback( GLenum flag )
 {
-   if (flag == GL_TRUE) {
-      triangle.color[0] = 1.0;
-      triangle.color[1] = 1.0;
-      triangle.color[2] = 0.5;
-   }
-   else {
-      triangle.color[0] = 1.0;
-      triangle.color[1] = 0.0;
-      triangle.color[2] = 0.0;
+   /* Persist the edge flag across triangles. */
+   if ( flag == GL_TRUE ) {
+      edge_color[0] = 1.0;
+      edge_color[1] = 1.0;
+      edge_color[2] = 0.5;
+   } else {
+      edge_color[0] = 1.0;
+      edge_color[1] = 0.0;
+      edge_color[2] = 0.0;
    }
 }
 
-
-static void GLCALLBACK
-end_callback()
+static void GLCALLBACK end_callback()
 {
-   glBegin(GL_LINES);
-   glColor3f(triangle.p_color[0][0], triangle.p_color[0][1],
-	     triangle.p_color[0][2]);
-   glVertex2i(triangle.p[0][0], triangle.p[0][1]);
-   glVertex2i(triangle.p[1][0], triangle.p[1][1]);
-   glColor3f(triangle.p_color[1][0], triangle.p_color[1][1],
-	     triangle.p_color[1][2]);
-   glVertex2i(triangle.p[1][0], triangle.p[1][1]);
-   glVertex2i(triangle.p[2][0], triangle.p[2][1]);
-   glColor3f(triangle.p_color[2][0], triangle.p_color[2][1],
-	     triangle.p_color[2][2]);
-   glVertex2i(triangle.p[2][0], triangle.p[2][1]);
-   glVertex2i(triangle.p[0][0], triangle.p[0][1]);
+   GLint	i;
+
+   glBegin( GL_LINES );
+
+   /* Output the three edges of each triangle as lines colored
+      according to their edge flag. */
+   for ( i = 0 ; i < triangle_cnt ; i++ ) {
+      glColor3f( triangles[i].color[0][0],
+		 triangles[i].color[0][1],
+		 triangles[i].color[0][2] );
+
+      glVertex2f( triangles[i].p[0][0], triangles[i].p[0][1] );
+      glVertex2f( triangles[i].p[1][0], triangles[i].p[1][1] );
+
+      glColor3f( triangles[i].color[1][0],
+		 triangles[i].color[1][1],
+		 triangles[i].color[1][2] );
+
+      glVertex2f( triangles[i].p[1][0], triangles[i].p[1][1] );
+      glVertex2f( triangles[i].p[2][0], triangles[i].p[2][1] );
+
+      glColor3f( triangles[i].color[2][0],
+		 triangles[i].color[2][1],
+		 triangles[i].color[2][2] );
+
+      glVertex2f( triangles[i].p[2][0], triangles[i].p[2][1] );
+      glVertex2f( triangles[i].p[0][0], triangles[i].p[0][1] );
+   }
+
    glEnd();
 }
 
+static void GLCALLBACK vertex_callback( void *data )
+{
+   GLsizei	no;
+   GLfloat	*p;
+
+   p = (GLfloat *) data;
+   no = triangles[triangle_cnt].no;
+
+   triangles[triangle_cnt].p[no][0] = p[0];
+   triangles[triangle_cnt].p[no][1] = p[1];
+
+   triangles[triangle_cnt].color[no][0] = edge_color[0];
+   triangles[triangle_cnt].color[no][1] = edge_color[1];
+   triangles[triangle_cnt].color[no][2] = edge_color[2];
 
-static void GLCALLBACK
-vertex_callback(void *data)
+   /* After every three vertices, initialize the next triangle. */
+   if ( ++(triangles[triangle_cnt].no) == 3 ) {
+      triangle_cnt++;
+      triangles[triangle_cnt].no = 0;
+   }
+}
+
+static void GLCALLBACK combine_callback( GLdouble coords[3],
+					 GLdouble *vertex_data[4],
+					 GLfloat weight[4], void **data )
 {
-   GLsizei no;
-   GLint *p;
-
-   p = (GLint *) data;
-   no = triangle.no;
-   triangle.p[no][0] = p[0];
-   triangle.p[no][1] = p[1];
-   triangle.p_color[no][0] = triangle.color[0];
-   triangle.p_color[no][1] = triangle.color[1];
-   triangle.p_color[no][2] = triangle.color[2];
-   ++(triangle.no);
+   GLfloat	*vertex;
+
+   vertex = (GLfloat *) malloc( 2 * sizeof(GLfloat) );
+
+   vertex[0] = (GLfloat) coords[0];
+   vertex[1] = (GLfloat) coords[1];
+
+   *data = vertex;
 }
 
 
-static void
-set_screen_wh(GLsizei w, GLsizei h)
+static void set_screen_wh( GLsizei w, GLsizei h )
 {
    width = w;
    height = h;
 }
 
-
-static void
-tesse(void)
+static void tesse( void )
 {
-   GLUtriangulatorObj *tobj;
-   GLdouble data[3];
-   GLuint i, j, point_cnt;
+   GLUtesselator	*tobj;
+   GLdouble		data[3];
+   GLuint		i, j, point_cnt;
+
+   list_start = glGenLists( 2 );
 
    tobj = gluNewTess();
-   if (tobj != NULL) {
-      glClear(GL_COLOR_BUFFER_BIT);
-      glColor3f(0.7, 0.7, 0.0);
-      gluTessCallback(tobj, GLU_BEGIN, glBegin);
-      gluTessCallback(tobj, GLU_END, glEnd);
-      gluTessCallback(tobj, GLU_ERROR, my_error);
-      gluTessCallback(tobj, GLU_VERTEX, glVertex2iv);
-      gluBeginPolygon(tobj);
-      for (j = 0; j <= contour_cnt; j++) {
+
+   if ( tobj != NULL ) {
+      gluTessNormal( tobj, 0.0, 0.0, 1.0 );
+      gluTessCallback( tobj, GLU_TESS_BEGIN, glBegin );
+      gluTessCallback( tobj, GLU_TESS_VERTEX, glVertex2fv );
+      gluTessCallback( tobj, GLU_TESS_END, glEnd );
+      gluTessCallback( tobj, GLU_TESS_ERROR, error_callback );
+      gluTessCallback( tobj, GLU_TESS_COMBINE, combine_callback );
+
+      glNewList( list_start, GL_COMPILE );
+      gluBeginPolygon( tobj );
+
+      for ( j = 0 ; j <= contour_cnt ; j++ ) {
 	 point_cnt = contours[j].point_cnt;
-	 gluNextContour(tobj, GLU_UNKNOWN);
-	 for (i = 0; i < point_cnt; i++) {
-	    data[0] = (GLdouble) (contours[j].p[i][0]);
-	    data[1] = (GLdouble) (contours[j].p[i][1]);
+	 gluNextContour( tobj, GLU_UNKNOWN );
+
+	 for ( i = 0 ; i < point_cnt ; i++ ) {
+	    data[0] = (GLdouble)( contours[j].p[i][0] );
+	    data[1] = (GLdouble)( contours[j].p[i][1] );
 	    data[2] = 0.0;
-	    gluTessVertex(tobj, data, contours[j].p[i]);
+	    gluTessVertex( tobj, data, contours[j].p[i] );
 	 }
       }
-      gluEndPolygon(tobj);
-      glLineWidth(2.0);
-      gluTessCallback(tobj, GLU_BEGIN, begin_callback);
-      gluTessCallback(tobj, GLU_END, end_callback);
-      gluTessCallback(tobj, GLU_VERTEX, vertex_callback);
-      gluTessCallback(tobj, GLU_EDGE_FLAG, edge_callback);
-      gluBeginPolygon(tobj);
-      for (j = 0; j <= contour_cnt; j++) {
+
+      gluEndPolygon( tobj );
+      glEndList();
+
+      gluTessCallback( tobj, GLU_TESS_BEGIN, begin_callback );
+      gluTessCallback( tobj, GLU_TESS_VERTEX, vertex_callback );
+      gluTessCallback( tobj, GLU_TESS_END, end_callback );
+      gluTessCallback( tobj, GLU_TESS_EDGE_FLAG, edge_callback );
+
+      glNewList( list_start + 1, GL_COMPILE );
+      gluBeginPolygon( tobj );
+
+      for ( j = 0 ; j <= contour_cnt ; j++ ) {
 	 point_cnt = contours[j].point_cnt;
-	 gluNextContour(tobj, GLU_UNKNOWN);
-	 for (i = 0; i < point_cnt; i++) {
-	    data[0] = (GLdouble) (contours[j].p[i][0]);
-	    data[1] = (GLdouble) (contours[j].p[i][1]);
+	 gluNextContour( tobj, GLU_UNKNOWN );
+
+	 for ( i = 0 ; i < point_cnt ; i++ ) {
+	    data[0] = (GLdouble)( contours[j].p[i][0] );
+	    data[1] = (GLdouble)( contours[j].p[i][1] );
 	    data[2] = 0.0;
-	    gluTessVertex(tobj, data, contours[j].p[i]);
+	    gluTessVertex( tobj, data, contours[j].p[i] );
 	 }
       }
-      gluEndPolygon(tobj);
-      gluDeleteTess(tobj);
-      glutMouseFunc(NULL);
-      glColor3f(1.0, 1.0, 0.0);
-      glLineWidth(1.0);
+
+      gluEndPolygon( tobj );
+      glEndList();
+
+      gluDeleteTess( tobj );
+
+      glutMouseFunc( NULL );
       mode = TESSELATED;
    }
 }
 
-
-static void
-left_down(int x1, int y1)
+static void left_down( int x1, int y1 )
 {
-   GLint P[2];
-   GLuint point_cnt;
+   GLfloat	P[2];
+   GLuint	point_cnt;
 
    /* translate GLUT into GL coordinates */
+
    P[0] = x1;
    P[1] = height - y1;
+
    point_cnt = contours[contour_cnt].point_cnt;
+
    contours[contour_cnt].p[point_cnt][0] = P[0];
    contours[contour_cnt].p[point_cnt][1] = P[1];
-   glBegin(GL_LINES);
-   if (point_cnt) {
-      glVertex2iv(contours[contour_cnt].p[point_cnt - 1]);
-      glVertex2iv(P);
-   }
-   else {
-      glVertex2iv(P);
-      glVertex2iv(P);
+
+   glBegin( GL_LINES );
+
+   if ( point_cnt ) {
+      glVertex2fv( contours[contour_cnt].p[point_cnt-1] );
+      glVertex2fv( P );
+   } else {
+      glVertex2fv( P );
+      glVertex2fv( P );
    }
+
    glEnd();
    glFinish();
-   ++(contours[contour_cnt].point_cnt);
-}
 
+   contours[contour_cnt].point_cnt++;
+}
 
-static void
-middle_down(int x1, int y1)
+static void middle_down( int x1, int y1 )
 {
-   GLuint point_cnt;
+   GLuint	point_cnt;
+   (void) x1;
+   (void) y1;
 
    point_cnt = contours[contour_cnt].point_cnt;
-   if (point_cnt > 2) {
-      glBegin(GL_LINES);
-      glVertex2iv(contours[contour_cnt].p[0]);
-      glVertex2iv(contours[contour_cnt].p[point_cnt - 1]);
+
+   if ( point_cnt > 2 ) {
+      glBegin( GL_LINES );
+
+      glVertex2fv( contours[contour_cnt].p[0] );
+      glVertex2fv( contours[contour_cnt].p[point_cnt-1] );
+
       contours[contour_cnt].p[point_cnt][0] = -1;
+
       glEnd();
       glFinish();
+
       contour_cnt++;
       contours[contour_cnt].point_cnt = 0;
    }
 }
 
-
-static void
-mouse_clicked(int button, int state, int x, int y)
+static void mouse_clicked( int button, int state, int x, int y )
 {
-   x -= x % 10;
-   y -= y % 10;
-   switch (button) {
+   x -= x%10;
+   y -= y%10;
+
+   switch ( button ) {
    case GLUT_LEFT_BUTTON:
-      if (state == GLUT_DOWN)
-	 left_down(x, y);
+      if ( state == GLUT_DOWN ) {
+	 left_down( x, y );
+      }
       break;
    case GLUT_MIDDLE_BUTTON:
-      if (state == GLUT_DOWN)
-	 middle_down(x, y);
+      if ( state == GLUT_DOWN ) {
+	 middle_down( x, y );
+      }
       break;
    }
 }
 
-
-static void
-display(void)
+static void display( void )
 {
-   GLuint i, j;
+   GLuint i,j;
    GLuint point_cnt;
 
-   glClear(GL_COLOR_BUFFER_BIT);
-   switch (mode) {
+   glClear( GL_COLOR_BUFFER_BIT );
+
+   switch ( mode ) {
    case DEFINE:
       /* draw grid */
-      glColor3f(0.6, 0.5, 0.5);
-      glBegin(GL_LINES);
-      for (i = 0; i < width; i += 10)
-	 for (j = 0; j < height; j += 10) {
-	    glVertex2i(0, j);
-	    glVertex2i(width, j);
-	    glVertex2i(i, height);
-	    glVertex2i(i, 0);
+      glColor3f( 0.6, 0.5, 0.5 );
+
+      glBegin( GL_LINES );
+
+      for ( i = 0 ; i < width ; i += 10 ) {
+	 for ( j = 0 ; j < height ; j += 10 ) {
+	    glVertex2i( 0, j );
+	    glVertex2i( width, j );
+	    glVertex2i( i, height );
+	    glVertex2i( i, 0 );
 	 }
+      }
+
       glEnd();
-      glColor3f(1.0, 1.0, 0.0);
-      for (i = 0; i <= contour_cnt; i++) {
+
+      glColor3f( 1.0, 1.0, 0.0 );
+
+      for ( i = 0 ; i <= contour_cnt ; i++ ) {
 	 point_cnt = contours[i].point_cnt;
-	 glBegin(GL_LINES);
-	 switch (point_cnt) {
+
+	 glBegin( GL_LINES );
+
+	 switch ( point_cnt ) {
 	 case 0:
 	    break;
 	 case 1:
-	    glVertex2iv(contours[i].p[0]);
-	    glVertex2iv(contours[i].p[0]);
+	    glVertex2fv( contours[i].p[0] );
+	    glVertex2fv( contours[i].p[0] );
 	    break;
 	 case 2:
-	    glVertex2iv(contours[i].p[0]);
-	    glVertex2iv(contours[i].p[1]);
+	    glVertex2fv( contours[i].p[0] );
+	    glVertex2fv( contours[i].p[1] );
 	    break;
 	 default:
 	    --point_cnt;
-	    for (j = 0; j < point_cnt; j++) {
-	       glVertex2iv(contours[i].p[j]);
-	       glVertex2iv(contours[i].p[j + 1]);
+	    for ( j = 0 ; j < point_cnt ; j++ ) {
+	       glVertex2fv( contours[i].p[j] );
+	       glVertex2fv( contours[i].p[j+1] );
 	    }
-	    if (contours[i].p[j + 1][0] == -1) {
-	       glVertex2iv(contours[i].p[0]);
-	       glVertex2iv(contours[i].p[j]);
+	    if ( contours[i].p[j+1][0] == -1 ) {
+	       glVertex2fv( contours[i].p[0] );
+	       glVertex2fv( contours[i].p[j] );
 	    }
 	    break;
 	 }
+
 	 glEnd();
       }
+
       glFinish();
       break;
+
    case TESSELATED:
-      /* draw lines */
-      tesse();
+      /* draw triangles */
+      glColor3f( 0.7, 0.7, 0.0 );
+      glCallList( list_start );
+
+      glLineWidth( 2.0 );
+      glCallList( list_start + 1 );
+      glLineWidth( 1.0 );
+
+      glFlush();
       break;
    }
 
-   glColor3f(1.0, 1.0, 0.0);
+   glColor3f( 1.0, 1.0, 0.0 );
 }
 
-
-static void
-clear(void)
+static void clear( void )
 {
    contour_cnt = 0;
    contours[0].point_cnt = 0;
-   glutMouseFunc(mouse_clicked);
+   triangle_cnt = 0;
+
+   glutMouseFunc( mouse_clicked );
+
    mode = DEFINE;
-   display();
-}
 
+   glDeleteLists( list_start, 2 );
+   list_start = 0;
+}
 
-static void
-quit(void)
+static void quit( void )
 {
-   exit(0);
+   exit( 0 );
 }
 
-
-static void
-menu_selected(int entry)
+static void menu_selected( int entry )
 {
-   switch (entry) {
+   switch ( entry ) {
    case CLEAR:
       clear();
       break;
       quit();
       break;
    }
-}
 
+   glutPostRedisplay();
+}
 
-static void
-key_pressed(unsigned char key, int x, int y)
+static void key_pressed( unsigned char key, int x, int y )
 {
-   switch (key) {
+   (void) x;
+   (void) y;
+
+   switch ( key ) {
+   case 'c':
+   case 'C':
+      clear();
+      break;
    case 't':
    case 'T':
       tesse();
-      glFinish();
       break;
    case 'q':
    case 'Q':
       quit();
       break;
-   case 'c':
-   case 'C':
-      clear();
-      break;
    }
-}
 
+   glutPostRedisplay();
+}
 
-static void
-myinit(void)
+static void myinit( void )
 {
-/*  clear background to gray	*/
-   glClearColor(0.4, 0.4, 0.4, 0.0);
-   glShadeModel(GL_FLAT);
-
-   menu = glutCreateMenu(menu_selected);
-   glutAddMenuEntry("clear", CLEAR);
-   glutAddMenuEntry("tesselate", TESSELATE);
-   glutAddMenuEntry("quit", QUIT);
-   glutAttachMenu(GLUT_RIGHT_BUTTON);
-   glutMouseFunc(mouse_clicked);
-   glutKeyboardFunc(key_pressed);
+   /* clear background to gray */
+   glClearColor( 0.4, 0.4, 0.4, 0.0 );
+   glShadeModel( GL_FLAT );
+   glPolygonMode( GL_FRONT, GL_FILL );
+
+   menu = glutCreateMenu( menu_selected );
+
+   glutAddMenuEntry( "clear", CLEAR );
+   glutAddMenuEntry( "tesselate", TESSELATE );
+   glutAddMenuEntry( "quit", QUIT );
+
+   glutAttachMenu( GLUT_RIGHT_BUTTON );
+
+   glutMouseFunc( mouse_clicked );
+   glutKeyboardFunc( key_pressed );
+
    contour_cnt = 0;
-   glPolygonMode(GL_FRONT, GL_FILL);
    mode = DEFINE;
 }
 
-
-static void
-reshape(GLsizei w, GLsizei h)
+static void reshape( GLsizei w, GLsizei h )
 {
-   glViewport(0, 0, w, h);
-   glMatrixMode(GL_PROJECTION);
+   glViewport( 0, 0, w, h );
+
+   glMatrixMode( GL_PROJECTION );
    glLoadIdentity();
-   glOrtho(0.0, (GLdouble) w, 0.0, (GLdouble) h, -1.0, 1.0);
-   glMatrixMode(GL_MODELVIEW);
+   glOrtho( 0.0, (GLdouble)w, 0.0, (GLdouble)h, -1.0, 1.0 );
+
+   glMatrixMode( GL_MODELVIEW );
    glLoadIdentity();
-   set_screen_wh(w, h);
+
+   set_screen_wh( w, h );
 }
 
 
-static void
-usage(void)
+static void usage( void )
 {
-   printf("Use left mouse button to place vertices.\n");
-   printf("Press middle mouse button when done.\n");
-   printf("Select tesselate from the pop-up menu.\n");
+   printf( "Use left mouse button to place vertices.\n" );
+   printf( "Press middle mouse button when done.\n" );
+   printf( "Select tesselate from the pop-up menu.\n" );
 }
 
+#endif
 
-/*  Main Loop
- *  Open window with initial window size, title bar, 
- *  RGBA display mode, and handle input events.
- */
-int
-main(int argc, char **argv)
+
+int main( int argc, char **argv )
 {
+   const char *version = (const char *) gluGetString( GLU_VERSION );
+   printf( "GLU version string: %s\n", version );
+   if ( strstr( version, "1.0" ) || strstr( version, "1.1" ) ) {
+      fprintf( stderr, "Sorry, this demo reqiures GLU 1.2 or later.\n" );
+      exit( 1 );
+   }
+
    usage();
-   glutInit(&argc, argv);
-   glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
-   glutInitWindowSize(400, 400);
-   glutCreateWindow(argv[0]);
+
+   glutInit( &argc, argv );
+   glutInitDisplayMode( GLUT_SINGLE | GLUT_RGB );
+   glutInitWindowSize( 400, 400 );
+   glutCreateWindow( argv[0] );
+
    myinit();
-   glutDisplayFunc(display);
-   glutReshapeFunc(reshape);
+
+   glutDisplayFunc( display );
+   glutReshapeFunc( reshape );
+
    glutMainLoop();
+
    return 0;
 }