Updated demo for new GLU 1.3 tessellation. Added optimized rendering
by saving the output of the tessellation into display lists.
diff --git a/progs/demos/tessdemo.c b/progs/demos/tessdemo.c
index c0d0242..7b3cf9e 100644
--- a/progs/demos/tessdemo.c
+++ b/progs/demos/tessdemo.c
@@ -1,4 +1,4 @@
-/* $Id: tessdemo.c,v 1.2 1999/09/19 20:09:00 tanner Exp $ */
+/* $Id: tessdemo.c,v 1.3 1999/11/04 04:00:42 gareth Exp $ */
/*
* A demo of the GLU polygon tesselation functions written by Bogdan Sikorski.
@@ -8,9 +8,16 @@
cc -g -ansi -prototypes -fullwarn -float -I../include -DSHM tess_demo.c -L../lib -lglut -lMesaGLU -lMesaGL -lm -lX11 -lXext -lXmu -lfpe -lXext -o tess_demo
*/
+/*
+ * Updated for GLU 1.3 tessellation by Gareth Hughes <garethh@bell-labs.com>
+ */
/*
* $Log: tessdemo.c,v $
+ * Revision 1.3 1999/11/04 04:00:42 gareth
+ * Updated demo for new GLU 1.3 tessellation. Added optimized rendering
+ * by saving the output of the tessellation into display lists.
+ *
* Revision 1.2 1999/09/19 20:09:00 tanner
*
* lots of autoconf updates
@@ -44,29 +51,9 @@
#include <stdlib.h>
#include <string.h>
-#define MAX_POINTS 200
-#define MAX_CONTOURS 50
-
-int menu;
-typedef enum{ QUIT, TESSELATE, CLEAR } menu_entries;
-typedef enum{ DEFINE, TESSELATED } mode_type;
-struct
-{
- GLint p[MAX_POINTS][2];
- GLuint point_cnt;
-} contours[MAX_CONTOURS];
-GLuint contour_cnt;
-GLsizei width,height;
-mode_type mode;
-
-struct
-{
- GLsizei no;
- GLfloat color[3];
- GLint p[3][2];
- GLclampf p_color[3][3];
-} triangle;
-
+#define MAX_POINTS 256
+#define MAX_CONTOURS 32
+#define MAX_TRIANGLES 256
#ifndef GLCALLBACK
#ifdef CALLBACK
@@ -76,368 +63,496 @@
#endif
#endif
+typedef enum{ QUIT, TESSELATE, CLEAR } menu_entries;
+typedef enum{ DEFINE, TESSELATED } mode_type;
-void GLCALLBACK my_error(GLenum err)
+static GLsizei width, height;
+static GLuint contour_cnt;
+static GLuint triangle_cnt;
+
+static mode_type mode;
+static int menu;
+
+static GLuint list_start;
+
+static GLfloat edge_color[3];
+
+static struct
{
- int len,i;
- char const *str;
+ GLint p[MAX_POINTS][2];
+ GLuint point_cnt;
+} contours[MAX_CONTOURS];
- 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 struct
+{
+ GLsizei no;
+ GLint p[3][2];
+ GLclampf color[3][3];
+} triangles[MAX_TRIANGLES];
+
+
+
+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] );
+ }
}
-void GLCALLBACK begin_callback(GLenum mode)
+void GLCALLBACK begin_callback( GLenum mode )
{
- triangle.no=0;
+ /* Allow multiple triangles to be output inside the begin/end pair. */
+ triangle_cnt = 0;
+ triangles[triangle_cnt].no = 0;
}
-void GLCALLBACK edge_callback(GLenum flag)
+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;
+ }
}
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]);
- glEnd();
+ 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] );
+
+ glVertex2i( triangles[i].p[0][0], triangles[i].p[0][1] );
+ glVertex2i( 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] );
+
+ glVertex2i( triangles[i].p[1][0], triangles[i].p[1][1] );
+ glVertex2i( 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] );
+
+ glVertex2i( triangles[i].p[2][0], triangles[i].p[2][1] );
+ glVertex2i( triangles[i].p[0][0], triangles[i].p[0][1] );
+ }
+
+ glEnd();
}
-void GLCALLBACK vertex_callback(void *data)
+void GLCALLBACK vertex_callback( void *data )
{
- GLsizei no;
- GLint *p;
+ 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);
+ p = (GLint *) 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];
+
+ /* After every three vertices, initialize the next triangle. */
+ if ( ++(triangles[triangle_cnt].no) == 3 )
+ {
+ triangle_cnt++;
+ triangles[triangle_cnt].no = 0;
+ }
}
-void set_screen_wh(GLsizei w, GLsizei h)
+void set_screen_wh( GLsizei w, GLsizei h )
{
- width=w;
- height=h;
+ width = w;
+ height = h;
}
-void tesse(void)
+void tesse( void )
{
- GLUtesselator *tobj;
- GLdouble data[3];
- GLuint i,j,point_cnt;
+ GLUtesselator *tobj;
+ GLdouble data[3];
+ GLuint i, j, point_cnt;
- 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++)
- {
- 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]);
- data[2]=0.0;
- 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++)
- {
- 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]);
- data[2]=0.0;
- gluTessVertex(tobj,data,contours[j].p[i]);
- }
- }
- gluEndPolygon(tobj);
- gluDeleteTess(tobj);
- glutMouseFunc(NULL);
- glColor3f (1.0, 1.0, 0.0);
- glLineWidth(1.0);
- mode=TESSELATED;
- }
+ list_start = glGenLists( 2 );
+
+ tobj = gluNewTess();
+
+ if ( tobj != NULL )
+ {
+ gluTessCallback( tobj, GLU_BEGIN, glBegin );
+ gluTessCallback( tobj, GLU_VERTEX, glVertex2iv );
+ gluTessCallback( tobj, GLU_END, glEnd );
+ gluTessCallback( tobj, GLU_ERROR, my_error );
+
+ 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] );
+ data[2] = 0.0;
+ gluTessVertex( tobj, data, contours[j].p[i] );
+ }
+ }
+
+ gluEndPolygon( tobj );
+ glEndList();
+
+ gluTessCallback( tobj, GLU_BEGIN, begin_callback );
+ gluTessCallback( tobj, GLU_VERTEX, vertex_callback );
+ gluTessCallback( tobj, GLU_END, end_callback );
+ gluTessCallback( tobj, GLU_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] );
+ data[2] = 0.0;
+ gluTessVertex( tobj, data, contours[j].p[i] );
+ }
+ }
+
+ gluEndPolygon( tobj );
+ glEndList();
+
+ gluDeleteTess( tobj );
+
+ glutMouseFunc( NULL );
+ mode = TESSELATED;
+ }
}
-void left_down(int x1,int y1)
+void left_down( int x1, int y1 )
{
- GLint P[2];
- GLuint point_cnt;
+ GLint 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);
- }
- glEnd();
- glFinish();
- ++(contours[contour_cnt].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 );
+ }
+
+ glEnd();
+ glFinish();
+
+ contours[contour_cnt].point_cnt++;
}
-void middle_down(int x1, int y1)
+void middle_down( int x1, int y1 )
{
- GLuint point_cnt;
- (void) x1;
- (void) y1;
+ 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]);
- contours[contour_cnt].p[point_cnt][0]= -1;
- glEnd();
- glFinish();
- contour_cnt++;
- contours[contour_cnt].point_cnt=0;
- }
+ 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] );
+
+ contours[contour_cnt].p[point_cnt][0] = -1;
+
+ glEnd();
+ glFinish();
+
+ contour_cnt++;
+ contours[contour_cnt].point_cnt = 0;
+ }
}
-void mouse_clicked(int button,int state,int x,int y)
+void mouse_clicked( int button, int state, int x, int y )
{
- x-= x%10;
- y-= y%10;
- switch(button)
- {
- case GLUT_LEFT_BUTTON:
- if(state==GLUT_DOWN)
- left_down(x,y);
- break;
- case GLUT_MIDDLE_BUTTON:
- if(state==GLUT_DOWN)
- middle_down(x,y);
- break;
- }
+ x -= x%10;
+ y -= y%10;
+
+ switch ( button )
+ {
+ case GLUT_LEFT_BUTTON:
+ if ( state == GLUT_DOWN ) {
+ left_down( x, y );
+ }
+ break;
+ case GLUT_MIDDLE_BUTTON:
+ if ( state == GLUT_DOWN ) {
+ middle_down( x, y );
+ }
+ break;
+ }
}
-void display(void)
+void display( void )
{
- GLuint i,j;
- GLuint point_cnt;
+ GLuint i,j;
+ GLuint point_cnt;
- 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 (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)
- {
- case 0:
- break;
- case 1:
- glVertex2iv(contours[i].p[0]);
- glVertex2iv(contours[i].p[0]);
- break;
- case 2:
- glVertex2iv(contours[i].p[0]);
- glVertex2iv(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]);
- }
- if(contours[i].p[j+1][0]== -1)
- {
- glVertex2iv(contours[i].p[0]);
- glVertex2iv(contours[i].p[j]);
- }
- break;
- }
- glEnd();
- }
- glFinish();
- break;
- case TESSELATED:
- /* draw lines */
- tesse();
- break;
- }
+ glClear( GL_COLOR_BUFFER_BIT );
- glColor3f (1.0, 1.0, 0.0);
+ 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( 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 )
+ {
+ case 0:
+ break;
+ case 1:
+ glVertex2iv( contours[i].p[0] );
+ glVertex2iv( contours[i].p[0] );
+ break;
+ case 2:
+ glVertex2iv( contours[i].p[0] );
+ glVertex2iv( 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] );
+ }
+ if ( contours[i].p[j+1][0] == -1 )
+ {
+ glVertex2iv( contours[i].p[0] );
+ glVertex2iv( contours[i].p[j] );
+ }
+ break;
+ }
+
+ glEnd();
+ }
+
+ glFinish();
+ break;
+
+ case TESSELATED:
+ /* 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 );
}
void clear( void )
{
- contour_cnt=0;
- contours[0].point_cnt=0;
- glutMouseFunc(mouse_clicked);
- mode=DEFINE;
- display();
+ contour_cnt = 0;
+ contours[0].point_cnt = 0;
+ triangle_cnt = 0;
+
+ glutMouseFunc( mouse_clicked );
+
+ mode = DEFINE;
+
+ glDeleteLists( list_start, 2 );
+ list_start = 0;
}
void quit( void )
{
- exit(0);
+ exit( 0 );
}
-void menu_selected(int entry)
+void menu_selected( int entry )
{
- switch(entry)
- {
- case CLEAR:
- clear();
- break;
- case TESSELATE:
- tesse();
- break;
- case QUIT:
- quit();
- break;
- }
+ switch ( entry )
+ {
+ case CLEAR:
+ clear();
+ break;
+ case TESSELATE:
+ tesse();
+ break;
+ case QUIT:
+ quit();
+ break;
+ }
+
+ glutPostRedisplay();
}
-void key_pressed(unsigned char key,int x,int y)
+void key_pressed( unsigned char key, int x, int y )
{
- (void) x;
- (void) y;
- switch(key)
- {
- case 't':
- case 'T':
- tesse();
- glFinish();
- break;
- case 'q':
- case 'Q':
- quit();
- break;
- case 'c':
- case 'C':
- clear();
- break;
- }
+ (void) x;
+ (void) y;
+
+ switch ( key )
+ {
+ case 'c':
+ case 'C':
+ clear();
+ break;
+ case 't':
+ case 'T':
+ tesse();
+ break;
+ case 'q':
+ case 'Q':
+ quit();
+ break;
+ }
+
+ glutPostRedisplay();
}
-void myinit (void)
+void myinit( void )
{
-/* clear background to gray */
- glClearColor (0.4, 0.4, 0.4, 0.0);
- glShadeModel (GL_FLAT);
+ /* 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;
+ 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;
+ mode = DEFINE;
}
-static void reshape(GLsizei w, GLsizei h)
+static void reshape( GLsizei w, GLsizei h )
{
- 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);
- glLoadIdentity();
- set_screen_wh(w,h);
+ 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 );
+ glLoadIdentity();
+
+ set_screen_wh( w, h );
}
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" );
}
-/* Main Loop
- * Open window with initial window size, title bar,
- * RGBA display mode, and handle input events.
+/*
+ * 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 )
{
- usage();
- glutInit(&argc, argv);
- glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
- glutInitWindowSize (400, 400);
- glutCreateWindow (argv[0]);
- myinit ();
- glutDisplayFunc(display);
- glutReshapeFunc(reshape);
- glutMainLoop();
- return 0;
+ usage();
+
+ glutInit( &argc, argv );
+ glutInitDisplayMode( GLUT_SINGLE | GLUT_RGB );
+ glutInitWindowSize( 400, 400 );
+ glutCreateWindow( argv[0] );
+
+ myinit();
+
+ glutDisplayFunc( display );
+ glutReshapeFunc( reshape );
+
+ glutMainLoop();
+
+ return 0;
}