weston/gears.c
2008-12-02 15:15:01 -05:00

239 lines
7.1 KiB
C

/*
* Copyright (C) 1999-2001 Brian Paul All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include <stdlib.h>
#include <math.h>
#include <GL/gl.h>
#include "gears.h"
struct gears {
GLint gear1, gear2, gear3;
};
static void
gear(GLfloat inner_radius, GLfloat outer_radius, GLfloat width,
GLint teeth, GLfloat tooth_depth)
{
GLint i;
GLfloat r0, r1, r2;
GLfloat angle, da;
GLfloat u, v, len;
r0 = inner_radius;
r1 = outer_radius - tooth_depth / 2.0;
r2 = outer_radius + tooth_depth / 2.0;
da = 2.0 * M_PI / teeth / 4.0;
glShadeModel(GL_FLAT);
glNormal3f(0.0, 0.0, 1.0);
/* draw front face */
glBegin(GL_QUAD_STRIP);
for (i = 0; i <= teeth; i++) {
angle = i * 2.0 * M_PI / teeth;
glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
if (i < teeth) {
glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);
}
}
glEnd();
/* draw front sides of teeth */
glBegin(GL_QUADS);
da = 2.0 * M_PI / teeth / 4.0;
for (i = 0; i < teeth; i++) {
angle = i * 2.0 * M_PI / teeth;
glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), width * 0.5);
glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);
}
glEnd();
glNormal3f(0.0, 0.0, -1.0);
/* draw back face */
glBegin(GL_QUAD_STRIP);
for (i = 0; i <= teeth; i++) {
angle = i * 2.0 * M_PI / teeth;
glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
if (i < teeth) {
glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);
glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
}
}
glEnd();
/* draw back sides of teeth */
glBegin(GL_QUADS);
da = 2.0 * M_PI / teeth / 4.0;
for (i = 0; i < teeth; i++) {
angle = i * 2.0 * M_PI / teeth;
glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);
glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), -width * 0.5);
glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
}
glEnd();
/* draw outward faces of teeth */
glBegin(GL_QUAD_STRIP);
for (i = 0; i < teeth; i++) {
angle = i * 2.0 * M_PI / teeth;
glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
u = r2 * cos(angle + da) - r1 * cos(angle);
v = r2 * sin(angle + da) - r1 * sin(angle);
len = sqrt(u * u + v * v);
u /= len;
v /= len;
glNormal3f(v, -u, 0.0);
glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
glNormal3f(cos(angle), sin(angle), 0.0);
glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), width * 0.5);
glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), -width * 0.5);
u = r1 * cos(angle + 3 * da) - r2 * cos(angle + 2 * da);
v = r1 * sin(angle + 3 * da) - r2 * sin(angle + 2 * da);
glNormal3f(v, -u, 0.0);
glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);
glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);
glNormal3f(cos(angle), sin(angle), 0.0);
}
glVertex3f(r1 * cos(0), r1 * sin(0), width * 0.5);
glVertex3f(r1 * cos(0), r1 * sin(0), -width * 0.5);
glEnd();
glShadeModel(GL_SMOOTH);
/* draw inside radius cylinder */
glBegin(GL_QUAD_STRIP);
for (i = 0; i <= teeth; i++) {
angle = i * 2.0 * M_PI / teeth;
glNormal3f(-cos(angle), -sin(angle), 0.0);
glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
}
glEnd();
}
struct gears *
gears_create(GLfloat clear_red, GLfloat clear_green,
GLfloat clear_blue, GLfloat clear_alpha)
{
static GLfloat red[4] = {0.8, 0.1, 0.0, 1.0};
static GLfloat green[4] = {0.0, 0.8, 0.2, 1.0};
static GLfloat blue[4] = {0.2, 0.2, 1.0, 1.0};
static GLfloat pos[4] = {5.0, 5.0, 10.0, 0.0};
struct gears *gears;
gears = malloc(sizeof *gears);
/* make the gears */
gears->gear1 = glGenLists(1);
glNewList(gears->gear1, GL_COMPILE);
glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, red);
gear(1.0, 4.0, 1.0, 20, 0.7);
glEndList();
gears->gear2 = glGenLists(1);
glNewList(gears->gear2, GL_COMPILE);
glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, green);
gear(0.5, 2.0, 2.0, 10, 0.7);
glEndList();
gears->gear3 = glGenLists(1);
glNewList(gears->gear3, GL_COMPILE);
glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, blue);
gear(1.3, 2.0, 0.5, 10, 0.7);
glEndList();
glEnable(GL_NORMALIZE);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 200.0);
glMatrixMode(GL_MODELVIEW);
glLightfv(GL_LIGHT0, GL_POSITION, pos);
glEnable(GL_CULL_FACE);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glEnable(GL_DEPTH_TEST);
/* We're generating premultiplied alpha so multiply in the
* alpha. The gears are solid color and doesn't have
* anti-aliased edges, they're ok. */
glClearColor(clear_red * clear_alpha,
clear_green * clear_alpha,
clear_blue * clear_alpha,
clear_alpha);
return gears;
}
void
gears_draw(struct gears *gears, GLfloat angle)
{
GLfloat view_rotx = 20.0, view_roty = 30.0, view_rotz = 0.0;
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glPushMatrix();
glTranslatef(0.0, 0.0, -50);
glRotatef(view_rotx, 1.0, 0.0, 0.0);
glRotatef(view_roty, 0.0, 1.0, 0.0);
glRotatef(view_rotz, 0.0, 0.0, 1.0);
glPushMatrix();
glTranslatef(-3.0, -2.0, 0.0);
glRotatef(angle, 0.0, 0.0, 1.0);
glCallList(gears->gear1);
glPopMatrix();
glPushMatrix();
glTranslatef(3.1, -2.0, 0.0);
glRotatef(-2.0 * angle - 9.0, 0.0, 0.0, 1.0);
glCallList(gears->gear2);
glPopMatrix();
glPushMatrix();
glTranslatef(-3.1, 4.2, 0.0);
glRotatef(-2.0 * angle - 25.0, 0.0, 0.0, 1.0);
glCallList(gears->gear3);
glPopMatrix();
glPopMatrix();
glFlush();
}