I drew a circle to represent a human face. I am drawing an arc to represent the mouth but I am having troubling positioning it in the right place. I have checked the value of x and y in the computation of the arc but can't seem to figure out what I am doing wrong or what I should be doing. I tried to redraw it again with other specifications but that is not working. glRotatef() and glTranslatef() doesn't seem to be helping that much either. Attached is a screen shot. The triangles represent the eyes but I'll worry about that later. I figured if I can understand how to position the arc right, I can do the same with the rest. Please help. It's a simple project and I need to turn it in today! Thanks.
#include <Windows.h>
#include <GL/glut.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
GLsizei winWidth = 600, winHeight = 600;
const float PI = 3.14159265;
const float Angle = 45;
void init(void)
{
glClearColor (0.0, 0.0, 1.0, 0.0);
glMatrixMode (GL_PROJECTION);
gluOrtho2D (0.0, winWidth, 0.0, winHeight);
glShadeModel (GL_SMOOTH);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
void triangles1()
{
glBegin( GL_TRIANGLES);
glColor3f(1.0, 0.0, 0.0);
glVertex2i(-25, 50);
glVertex2i(50, 75);
glVertex2i(20, 50);
glEnd();
}
void drawTriangle()
{
glPushMatrix();
glTranslatef(160, 160, 0);
glTranslatef(100, 10, 0);
glRotatef(Angle, 0, 0, 0);
//glScalef(1, 1, 1);
glClear(GL_COLOR_BUFFER_BIT);
glBegin( GL_TRIANGLES);
glColor3f(1.0, 0.0, 0.0);
glVertex2i(100, 500);
glVertex2i(0, 666);
glVertex2i(200, 666);
glEnd();
glBegin( GL_TRIANGLES);
glColor3f(1.0, 0.0, 0.0);
glVertex2i(600, 650);
glVertex2i(450, 750);
glVertex2i(300, 650);
glEnd();
glPopMatrix();
}
void circle(GLint x, GLint y, GLint radius)
{
float angle;
glTranslatef(170, 100, 0.0);
glTranslatef(0.0,70, 1.0);
glColor3f(0.0f, 1.0f, 0.0f);
glBegin(GL_LINE_LOOP);
for (int i = 0; i < 100; i++)
{
angle = i*2*PI/100;
float X = x + (cos(angle) * radius);
float Y = y + (sin(angle) * radius);
glVertex2f(X, Y);
//glVertex2f(x + (cos(angle) * radius), y + (sin(angle) * radius));
}
glEnd();
}
void drawArc(float x, float y, float r, float t0, float sweep)
{
float t, dt; /* angle */
int n = 100; /* # of segments */
int i;
t = t0 * PI/270.0; /* radians */
dt = sweep * PI/(270*n); /* increment */
glLoadIdentity();
glTranslatef(50, 150, 0);
glTranslatef(200, 50, 0);
glRotatef(60, 0, 0, 0);
glBegin(GL_LINE_STRIP);
glColor3f(0.0, 1.0, 0.0);
for(i=0; i<=n; i++, t += dt)
glVertex2f(x + r*cos(t), y + r*sin(t));
glEnd();
}
void display(void)
{
glPushMatrix();
glTranslatef(100, 100, 0);
glClear(GL_COLOR_BUFFER_BIT);
/* glPushMatrix();
glTranslatef(100, 100, 0);
glRotatef(100, 100, 100, 100);*/
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(0.0, 0.0, 0.0);
glRotatef(Angle, 0.0, 0.0, 0.0);
drawTriangle();
circle (250, 250, 350);
drawArc(-50, 50, -180, -180, 180);
glFlush(); /* Single buffered, so needs a flush. */
}
void reshape (int w, int h)
{
glViewport(0, 0, (GLsizei) w, (GLsizei) h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(-60.0, (GLfloat) w/(GLfloat) h, 1.0, 20.0);
glMatrixMode(GL_MODELVIEW);
}
int main (int argc, char** argv)
{
glutInit (&argc, argv); // Initialize GLUT
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
glutInitWindowPosition (100, 100);
glutInitWindowSize (winWidth, winHeight); // Set the initial Window's width and height
glutCreateWindow ("Facial Expression Program");// Create window with the given title
init(); // Our own OpenGL initialization
glutDisplayFunc (display); // Register callback handler for window re-paint event
//glutReshapeFunc(reshape);
glutMainLoop ( ); // Enter infinitely event-processing loop
}
