// 1.  Complete routine 'lowerArm', which renders a lower arm, sitting on the x-z plane,
//     as presented in class.  This lower arm should rotate, positively in some direction 
//     (x , y , or z) when 'l' is pressed and negatively when 'L' is pressed.
//     Scale this arm as desired.
//
//     You should render only the lower arm and confirm that is works, before
//     continuing.
//
// 2.  Complete routine 'upperArm', which renders the upper arm, sitting on the x-z plane,
//     as presented in class.  This upper arm should rotate, positively in some direction 
//     (x , y , or z) when 'u' is pressed and negatively when 'U' is pressed.
//     Provide some appropriate scaling for this arm.
//
// 3.  Render the lower and upper arms at the same time, and so they are "flush" initially.
//
// 4.  If you complete your code during class time, demo it for the instructor.  Otherwise, 
//	   hand in the complete and correct source at the beginning of the next class.
//

#define LOWER_ARM_WIDTH 0.5
#define LOWER_ARM_HEIGHT 2.0

#define UPPER_ARM_WIDTH 0.25
#define UPPER_ARM_HEIGHT 1.0


#include <GL/glut.h>
#include <cstdlib>

GLint ldegree=0, udegree=0;

void myInit()
{
	glClearColor( 1.0 , 1.0 , 1.0 , 1.0 );

	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glOrtho(-2,2,-2,2,1.5,10);
	glMatrixMode(GL_MODELVIEW);

	glLoadIdentity();
	gluLookAt(3,3,3,0,0,0,0,1,0);
}

void lowerArm()
{
	glPushMatrix();
	glTranslatef(0 , 0.5*LOWER_ARM_HEIGHT , 0);
	glScalef(LOWER_ARM_WIDTH , LOWER_ARM_HEIGHT , LOWER_ARM_WIDTH);
	glutWireCube(1.0);
	glPopMatrix();
}

void upperArm()
{
	glPushMatrix();
	glTranslatef(0 , 0.5*UPPER_ARM_HEIGHT , 0);
	glScalef(UPPER_ARM_WIDTH , UPPER_ARM_HEIGHT , UPPER_ARM_WIDTH);
	glutWireCube(1.0);
	glPopMatrix();
}

void display()
{
	glClear(GL_COLOR_BUFFER_BIT);
	glColor3f(1.0 , 0.0 , 0.0);

	// why are these three lines here?
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	gluLookAt(3,3,3,0,0,0,0,1,0);

	glRotatef(ldegree,0,0,1);
	lowerArm();

	glTranslatef(0 , LOWER_ARM_HEIGHT , 0 );
	glRotatef(udegree,0,0,1);
	upperArm();

	glFlush();
	

}

void keyboard(unsigned char key, GLint x, GLint y)
{
	switch (key)
	{
	case 'l':
		ldegree=(ldegree+4);
		glutPostRedisplay();
		break;

	case 'L':
		ldegree=(ldegree-4)%360;
		glutPostRedisplay();
		break;

	case 'u':
		udegree=(udegree+4)%360;
		glutPostRedisplay();
		break;

	case 'U':
		udegree=(udegree-4)%360;
		glutPostRedisplay();
		break;

	case 'q':
		exit( 0 );

	}

	glutPostRedisplay();

	return;
}

int main (int argc , char **argv)
{
	glutInit(&argc,argv);
	glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
	glutInitWindowSize(400,400);
	glutInitWindowPosition(100,100);
	glutCreateWindow("cube");
	myInit();
	glutDisplayFunc(display);
	glutKeyboardFunc(keyboard);
	glutMainLoop();

	return 0;
}