440 lines
8.6 KiB
C
440 lines
8.6 KiB
C
/* $Id: tessdemo.c,v 1.1 1999/08/19 00:55:40 jtg Exp $ */
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/*
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* A demo of the GLU polygon tesselation functions written by Bogdan Sikorski.
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* This demo isn't built by the Makefile because it needs GLUT. After you've
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* installed GLUT you can try this demo.
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* Here's the command for IRIX, for example:
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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
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*/
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/*
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* $Log: tessdemo.c,v $
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* Revision 1.1 1999/08/19 00:55:40 jtg
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* Initial revision
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*
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* Revision 3.5 1999/03/28 18:24:37 brianp
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* minor clean-up
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*
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* Revision 3.4 1999/02/14 03:37:07 brianp
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* fixed callback problem
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*
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* Revision 3.3 1998/07/26 01:25:26 brianp
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* removed include of gl.h and glu.h
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*
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* Revision 3.2 1998/06/29 02:37:30 brianp
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* minor changes for Windows (Ted Jump)
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*
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* Revision 3.1 1998/06/09 01:53:49 brianp
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* main() should return an int
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*
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* Revision 3.0 1998/02/14 18:42:29 brianp
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* initial rev
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*
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*/
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#include <GL/glut.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#define MAX_POINTS 200
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#define MAX_CONTOURS 50
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int menu;
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typedef enum{ QUIT, TESSELATE, CLEAR } menu_entries;
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typedef enum{ DEFINE, TESSELATED } mode_type;
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struct
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{
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GLint p[MAX_POINTS][2];
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GLuint point_cnt;
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} contours[MAX_CONTOURS];
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GLuint contour_cnt;
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GLsizei width,height;
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mode_type mode;
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struct
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{
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GLsizei no;
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GLfloat color[3];
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GLint p[3][2];
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GLclampf p_color[3][3];
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} triangle;
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#ifndef GLCALLBACK
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#ifdef CALLBACK
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#define GLCALLBACK CALLBACK
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#else
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#define GLCALLBACK
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#endif
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#endif
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void GLCALLBACK my_error(GLenum err)
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{
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int len,i;
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char const *str;
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glColor3f(0.9,0.9,0.9);
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glRasterPos2i(5,5);
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str=(const char *)gluErrorString(err);
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len=strlen(str);
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for(i=0;i<len;i++)
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glutBitmapCharacter(GLUT_BITMAP_9_BY_15,str[i]);
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}
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void GLCALLBACK begin_callback(GLenum mode)
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{
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triangle.no=0;
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}
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void GLCALLBACK edge_callback(GLenum flag)
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{
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if(flag==GL_TRUE)
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{
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triangle.color[0]=1.0;
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triangle.color[1]=1.0;
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triangle.color[2]=0.5;
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}
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else
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{
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triangle.color[0]=1.0;
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triangle.color[1]=0.0;
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triangle.color[2]=0.0;
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}
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}
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void GLCALLBACK end_callback()
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{
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glBegin(GL_LINES);
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glColor3f(triangle.p_color[0][0],triangle.p_color[0][1],
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triangle.p_color[0][2]);
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glVertex2i(triangle.p[0][0],triangle.p[0][1]);
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glVertex2i(triangle.p[1][0],triangle.p[1][1]);
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glColor3f(triangle.p_color[1][0],triangle.p_color[1][1],
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triangle.p_color[1][2]);
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glVertex2i(triangle.p[1][0],triangle.p[1][1]);
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glVertex2i(triangle.p[2][0],triangle.p[2][1]);
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glColor3f(triangle.p_color[2][0],triangle.p_color[2][1],
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triangle.p_color[2][2]);
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glVertex2i(triangle.p[2][0],triangle.p[2][1]);
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glVertex2i(triangle.p[0][0],triangle.p[0][1]);
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glEnd();
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}
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void GLCALLBACK vertex_callback(void *data)
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{
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GLsizei no;
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GLint *p;
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p=(GLint *)data;
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no=triangle.no;
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triangle.p[no][0]=p[0];
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triangle.p[no][1]=p[1];
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triangle.p_color[no][0]=triangle.color[0];
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triangle.p_color[no][1]=triangle.color[1];
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triangle.p_color[no][2]=triangle.color[2];
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++(triangle.no);
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}
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void set_screen_wh(GLsizei w, GLsizei h)
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{
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width=w;
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height=h;
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}
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void tesse(void)
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{
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GLUtriangulatorObj *tobj;
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GLdouble data[3];
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GLuint i,j,point_cnt;
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tobj=gluNewTess();
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if(tobj!=NULL)
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{
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glClear(GL_COLOR_BUFFER_BIT);
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glColor3f (0.7, 0.7, 0.0);
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gluTessCallback(tobj,GLU_BEGIN,glBegin);
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gluTessCallback(tobj,GLU_END,glEnd);
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gluTessCallback(tobj,GLU_ERROR,my_error);
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gluTessCallback(tobj,GLU_VERTEX,glVertex2iv);
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gluBeginPolygon(tobj);
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for(j=0;j<=contour_cnt;j++)
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{
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point_cnt=contours[j].point_cnt;
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gluNextContour(tobj,GLU_UNKNOWN);
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for(i=0;i<point_cnt;i++)
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{
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data[0]=(GLdouble)(contours[j].p[i][0]);
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data[1]=(GLdouble)(contours[j].p[i][1]);
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data[2]=0.0;
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gluTessVertex(tobj,data,contours[j].p[i]);
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}
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}
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gluEndPolygon(tobj);
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glLineWidth(2.0);
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gluTessCallback(tobj,GLU_BEGIN,begin_callback);
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gluTessCallback(tobj,GLU_END,end_callback);
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gluTessCallback(tobj,GLU_VERTEX,vertex_callback);
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gluTessCallback(tobj,GLU_EDGE_FLAG,edge_callback);
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gluBeginPolygon(tobj);
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for(j=0;j<=contour_cnt;j++)
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{
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point_cnt=contours[j].point_cnt;
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gluNextContour(tobj,GLU_UNKNOWN);
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for(i=0;i<point_cnt;i++)
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{
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data[0]=(GLdouble)(contours[j].p[i][0]);
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data[1]=(GLdouble)(contours[j].p[i][1]);
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data[2]=0.0;
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gluTessVertex(tobj,data,contours[j].p[i]);
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}
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}
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gluEndPolygon(tobj);
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gluDeleteTess(tobj);
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glutMouseFunc(NULL);
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glColor3f (1.0, 1.0, 0.0);
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glLineWidth(1.0);
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mode=TESSELATED;
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}
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}
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void left_down(int x1,int y1)
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{
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GLint P[2];
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GLuint point_cnt;
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/* translate GLUT into GL coordinates */
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P[0]=x1;
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P[1]=height-y1;
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point_cnt=contours[contour_cnt].point_cnt;
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contours[contour_cnt].p[point_cnt][0]=P[0];
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contours[contour_cnt].p[point_cnt][1]=P[1];
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glBegin(GL_LINES);
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if(point_cnt)
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{
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glVertex2iv(contours[contour_cnt].p[point_cnt-1]);
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glVertex2iv(P);
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}
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else
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{
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glVertex2iv(P);
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glVertex2iv(P);
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}
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glEnd();
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glFinish();
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++(contours[contour_cnt].point_cnt);
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}
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void middle_down(int x1, int y1)
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{
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GLuint point_cnt;
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(void) x1;
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(void) y1;
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point_cnt=contours[contour_cnt].point_cnt;
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if(point_cnt>2)
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{
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glBegin(GL_LINES);
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glVertex2iv(contours[contour_cnt].p[0]);
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glVertex2iv(contours[contour_cnt].p[point_cnt-1]);
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contours[contour_cnt].p[point_cnt][0]= -1;
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glEnd();
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glFinish();
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contour_cnt++;
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contours[contour_cnt].point_cnt=0;
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}
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}
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void mouse_clicked(int button,int state,int x,int y)
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{
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x-= x%10;
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y-= y%10;
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switch(button)
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{
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case GLUT_LEFT_BUTTON:
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if(state==GLUT_DOWN)
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left_down(x,y);
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break;
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case GLUT_MIDDLE_BUTTON:
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if(state==GLUT_DOWN)
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middle_down(x,y);
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break;
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}
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}
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void display(void)
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{
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GLuint i,j;
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GLuint point_cnt;
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glClear(GL_COLOR_BUFFER_BIT);
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switch(mode)
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{
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case DEFINE:
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/* draw grid */
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glColor3f (0.6,0.5,0.5);
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glBegin(GL_LINES);
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for(i=0;i<width;i+=10)
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for(j=0;j<height;j+=10)
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{
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glVertex2i(0,j);
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glVertex2i(width,j);
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glVertex2i(i,height);
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glVertex2i(i,0);
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}
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glColor3f (1.0, 1.0, 0.0);
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for(i=0;i<=contour_cnt;i++)
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{
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point_cnt=contours[i].point_cnt;
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glBegin(GL_LINES);
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switch(point_cnt)
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{
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case 0:
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break;
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case 1:
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glVertex2iv(contours[i].p[0]);
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glVertex2iv(contours[i].p[0]);
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break;
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case 2:
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glVertex2iv(contours[i].p[0]);
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glVertex2iv(contours[i].p[1]);
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break;
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default:
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--point_cnt;
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for(j=0;j<point_cnt;j++)
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{
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glVertex2iv(contours[i].p[j]);
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glVertex2iv(contours[i].p[j+1]);
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}
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if(contours[i].p[j+1][0]== -1)
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{
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glVertex2iv(contours[i].p[0]);
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glVertex2iv(contours[i].p[j]);
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}
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break;
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}
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glEnd();
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}
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glFinish();
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break;
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case TESSELATED:
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/* draw lines */
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tesse();
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break;
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}
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glColor3f (1.0, 1.0, 0.0);
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}
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void clear( void )
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{
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contour_cnt=0;
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contours[0].point_cnt=0;
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glutMouseFunc(mouse_clicked);
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mode=DEFINE;
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display();
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}
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void quit( void )
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{
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exit(0);
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}
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void menu_selected(int entry)
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{
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switch(entry)
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{
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case CLEAR:
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clear();
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break;
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case TESSELATE:
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tesse();
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break;
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case QUIT:
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quit();
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break;
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}
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}
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void key_pressed(unsigned char key,int x,int y)
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{
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(void) x;
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(void) y;
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switch(key)
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{
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case 't':
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case 'T':
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tesse();
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glFinish();
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break;
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case 'q':
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case 'Q':
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quit();
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break;
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case 'c':
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case 'C':
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clear();
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break;
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}
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}
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void myinit (void)
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{
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/* clear background to gray */
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glClearColor (0.4, 0.4, 0.4, 0.0);
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glShadeModel (GL_FLAT);
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menu=glutCreateMenu(menu_selected);
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glutAddMenuEntry("clear",CLEAR);
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glutAddMenuEntry("tesselate",TESSELATE);
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glutAddMenuEntry("quit",QUIT);
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glutAttachMenu(GLUT_RIGHT_BUTTON);
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glutMouseFunc(mouse_clicked);
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glutKeyboardFunc(key_pressed);
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contour_cnt=0;
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glPolygonMode(GL_FRONT,GL_FILL);
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mode=DEFINE;
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}
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static void reshape(GLsizei w, GLsizei h)
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{
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glViewport(0, 0, w, h);
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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glOrtho(0.0, (GLdouble)w, 0.0, (GLdouble)h, -1.0, 1.0);
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glMatrixMode(GL_MODELVIEW);
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glLoadIdentity();
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set_screen_wh(w,h);
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}
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static void usage( void )
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{
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printf("Use left mouse button to place vertices.\n");
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printf("Press middle mouse button when done.\n");
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printf("Select tesselate from the pop-up menu.\n");
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}
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/* Main Loop
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* Open window with initial window size, title bar,
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* RGBA display mode, and handle input events.
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*/
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int main(int argc, char** argv)
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{
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usage();
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glutInit(&argc, argv);
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glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
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glutInitWindowSize (400, 400);
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glutCreateWindow (argv[0]);
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myinit ();
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glutDisplayFunc(display);
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glutReshapeFunc(reshape);
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glutMainLoop();
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return 0;
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}
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