Initial revision

1 files changed, 439 insertions, 0 deletions

diff --git a/progs/demos/tessdemo.c b/progs/demos/tessdemo.c
new file mode 100644
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+/* $Id: tessdemo.c,v 1.1 1999/08/19 00:55:40 jtg Exp $ */
+
+/*
+ * A demo of the GLU polygon tesselation functions written by Bogdan Sikorski.
+ * This demo isn't built by the Makefile because it needs GLUT.  After you've
+ * installed GLUT you can try this demo.
+ * Here's the command for IRIX, for example:
+   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
+ */
+
+
+/*
+ * $Log: tessdemo.c,v $
+ * Revision 1.1  1999/08/19 00:55:40  jtg
+ * Initial revision
+ *
+ * Revision 3.5  1999/03/28 18:24:37  brianp
+ * minor clean-up
+ *
+ * Revision 3.4  1999/02/14 03:37:07  brianp
+ * fixed callback problem
+ *
+ * Revision 3.3  1998/07/26 01:25:26  brianp
+ * removed include of gl.h and glu.h
+ *
+ * Revision 3.2  1998/06/29 02:37:30  brianp
+ * minor changes for Windows (Ted Jump)
+ *
+ * Revision 3.1  1998/06/09 01:53:49  brianp
+ * main() should return an int
+ *
+ * Revision 3.0  1998/02/14 18:42:29  brianp
+ * initial rev
+ *
+ */
+
+
+#include <GL/glut.h>
+#include <stdio.h>
+#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;
+
+
+#ifndef GLCALLBACK
+#ifdef CALLBACK
+#define GLCALLBACK CALLBACK
+#else
+#define GLCALLBACK
+#endif
+#endif
+
+
+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)
+{
+	triangle.no=0;
+}
+
+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;
+	}
+}
+
+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();
+}
+
+void GLCALLBACK vertex_callback(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);
+}
+
+void set_screen_wh(GLsizei w, GLsizei h)
+{
+	width=w;
+	height=h;
+}
+
+void tesse(void)
+{
+	GLUtriangulatorObj *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;
+	}
+}
+
+void left_down(int x1,int y1)
+{
+	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);
+}
+
+void middle_down(int x1, int 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;
+	}
+}
+
+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;
+	}
+}
+
+void display(void)
+{
+	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;
+	}
+
+    glColor3f (1.0, 1.0, 0.0);
+}
+
+void clear( void )
+{
+    contour_cnt=0;
+    contours[0].point_cnt=0;
+	glutMouseFunc(mouse_clicked);
+	mode=DEFINE;
+	display();
+}
+
+void quit( void )
+{
+	exit(0);
+}
+
+void menu_selected(int entry)
+{
+	switch(entry)
+	{
+		case CLEAR:
+			clear();
+			break;
+		case TESSELATE:
+			tesse();
+			break;
+		case QUIT:
+			quit();
+			break;
+	}
+}
+
+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 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);
+    contour_cnt=0;
+    glPolygonMode(GL_FRONT,GL_FILL);
+    mode=DEFINE;
+}
+
+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);
+}
+
+
+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");
+}
+
+
+/*  Main Loop
+ *  Open window with initial window size, title bar, 
+ *  RGBA display mode, and handle input events.
+ */
+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;
+}