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/* Copyright (c) Mark J. Kilgard, 1994. */
/* This program is freely distributable without licensing fees
and is provided without guarantee or warrantee expressed or
implied. This program is -not- in the public domain. */
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <GL/glut.h>
#define NUM_DIALS 8
#define NUM_BUTTONS 32
int *dials, *buttons;
#undef PI /* Some systems may have this defined. */
#define PI 3.14159265358979323846
void
drawCircle(int x, int y, int r, int dir)
{
float angle;
glPushMatrix();
glTranslatef(x,y,0);
glBegin(GL_TRIANGLE_FAN);
glVertex2f(0,0);
for(angle = 2*PI; angle >= 0; angle -= PI/12) {
glVertex2f(r*cos(angle),r*sin(angle));
}
glEnd();
glColor3f(0,0,1);
glBegin(GL_LINES);
glVertex2f(0,0);
glVertex2f(r*cos(dir*PI/180),r*sin(dir*PI/180));
glEnd();
glPopMatrix();
}
void
displayDials(void)
{
int i;
for(i=0;i<NUM_DIALS;i++) {
glColor3f(0, 1, 0);
drawCircle(60 + ((i+1)%2) * 100, 60 + (i/2) * 100, 40, dials[NUM_DIALS-1-i]-90);
}
}
void
displayButtons(void)
{
int i, n;
glBegin(GL_QUADS);
for(i=0,n=0;i<NUM_BUTTONS;i++,n++) {
switch(n) {
case 0:
case 5:
case 30:
n++;
}
if(buttons[i]) {
glColor3f(1,0,0);
} else {
glColor3f(1,1,1);
}
glVertex2f((n%6)*40+250,(n/6)*40+10);
glVertex2f((n%6)*40+270,(n/6)*40+10);
glVertex2f((n%6)*40+270,(n/6)*40+30);
glVertex2f((n%6)*40+250,(n/6)*40+30);
}
glEnd();
}
void
display(void)
{
glClear(GL_COLOR_BUFFER_BIT);
displayDials();
displayButtons();
glutSwapBuffers();
}
void
reshape(int w, int h)
{
glViewport(0, 0, w, h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluOrtho2D(0, w, 0, h);
glScalef(1, -1, 1);
glTranslatef(0, -h, 0);
}
void
dodial(int dial, int value)
{
if(dial > 0 && dial <= NUM_DIALS) {
dials[dial - 1] = value % 360;
glutPostRedisplay();
}
}
void
dobutton(int button, int state)
{
if(button > 0 && button <= NUM_BUTTONS) {
buttons[button-1] = (state == GLUT_DOWN);
glutPostRedisplay();
}
}
int
main(int argc, char **argv)
{
int width, height;
glutInit(&argc, argv);
dials = (int*) calloc(NUM_DIALS, sizeof(int));
buttons = (int*) calloc(NUM_BUTTONS, sizeof(int));
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
width = 240 + 240;
height = 100*((NUM_DIALS+1)/2) + 20;
if(height < 240) height = 240;
glutInitWindowSize(width, height);
glutCreateWindow("GLUT dials & buttons");
glClearColor(0.5, 0.5, 0.5, 1.0);
glLineWidth(3.0);
glutDialsFunc(dodial);
glutButtonBoxFunc(dobutton);
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutInitWindowSize(240, 240);
glutMainLoop();
return 0; /* ANSI C requires main to return int. */
}
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