Add the gears from glxgears.

1 files changed, 207 insertions, 0 deletions

diff --git a/gears.c b/gears.c
new file mode 100644
index 0000000..db79d4d
--- /dev/null
+++ b/gears.c
@@ -0,0 +1,207 @@
+#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(void)
+{
+	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);
+
+	return gears;
+}
+
+void
+gears_draw(struct gears *gears, GLfloat angle)
+{
+	GLfloat view_rotx = 20.0, view_roty = 30.0, view_rotz = 0.0;
+
+	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();
+}