#include "glut.h"
#include <ctype.h>

// camera position
float camY = 5.f;
float camZ = 10.f;

void init()
{
	// rendering states
	glEnable(GL_DEPTH_TEST);
	glEnable(GL_NORMALIZE);
	glShadeModel(GL_SMOOTH);
	glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
	glEnable(GL_LIGHTING);
	glEnable(GL_LIGHT0);

	GLfloat clrWhite[] = { 1.0f, 1.0f, 1.0f };
	GLfloat posLight[] = { 3.0f, 3.0f, 0.0f, 1.0f };
	glLightfv(GL_LIGHT0, GL_AMBIENT, clrWhite);	// ambient light colour
	glLightfv(GL_LIGHT0, GL_DIFFUSE, clrWhite);	// diffuse light colour
	glLightfv(GL_LIGHT0, GL_POSITION, posLight);	// light position


}
void render()
{
	static float theta = 0.0f;

	// clear screen and buffers
	glClearColor(0.18f, 0.25f, 0.22f, 1.0f);   // deep grey background
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	// setup the view point
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	gluLookAt(0.0, camY, camZ,
		0.0, camY - 5, camZ - 15,
		0.0, 1.0, 0.0);

	//camera
	glRotatef(theta, 0.0f, 1.0f, 0.0f);

	//material
	float clr2[] = { 0.0f, 0.0f, 0.0f };
	float clr[] = { 0.8f, 0.8f, 0.8f };


	//render
	glTranslatef(3.0f, -1.0f, 1.0f);
	glRotatef(-theta, 1.0f, 1.0f, 0.0f);
	glMaterialfv(GL_FRONT, GL_DIFFUSE, clr);
	glutSolidTeapot(2.0);
	glMaterialfv(GL_FRONT, GL_DIFFUSE, clr2);
	glutWireTeapot(2.02);



	//animation
	static GLint prev_time = 0;
	int time = glutGet(GLUT_ELAPSED_TIME);
	theta += (time - prev_time) * 0.01;
	prev_time = time;
	glutPostRedisplay();

	// essential for double-buffering technique
	glutSwapBuffers();

}
void reshape(int w, int h)
{
	// find screen aspect ratio
	float ratio = w * 1.0 / h;      // we hope that h is not zero

									// setup the projection matrix
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glViewport(0, 0, w, h);
	gluPerspective(60.0f, ratio, 1.0f, 100.0f);

	// set model/view matrix for rendering
	glMatrixMode(GL_MODELVIEW);

}
void onKeyDown(unsigned char key, int x, int y)
{

	switch (tolower(key))
	{
	case 'w': camZ -= 0.4; break;
	case 's': camZ += 0.4; break;
	case 'x': camY += 0.4; break;
	case 'z': camY -= 0.4; break;
	}

}
int main(int argc, char **argv)
{


	// init GLUT and create Window
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
	glutInitWindowPosition(100, 100);
	glutInitWindowSize(800, 600);
	glutCreateWindow("CI5520 3D Graphics Programming");

	// register callbacks
	glutDisplayFunc(render);
	glutReshapeFunc(reshape);
	glutKeyboardFunc(onKeyDown);

	// init light and everything – not a GLUT or callback function!
	init();

	// enter GLUT event processing cycle
	glutMainLoop();


	return 1;
}