/* $Id$ */
#include <Mw/Milsko.h>
#include <Mw/OpenGL.h>

#include <GL/gl.h>

MwWidget opengl;

/*
 * Bouncing ball demo.
 *
 * This program is in the public domain
 *
 * Brian Paul
 */

#include <math.h>
#include <stdlib.h>

#define COS(X) cos((X) * 3.14159 / 180.0)
#define SIN(X) sin((X) * 3.14159 / 180.0)

#define RED 1.0, 0.0, 0.0
#define WHITE 1.0, 1.0, 1.0
#define CYAN 0.0, 1.0, 1.0

GLuint	Ball;
GLenum	Mode;
GLfloat Zrot = 0.0, Zstep = 6.0;
GLfloat Xpos = 0.0, Ypos = 1.0;
GLfloat Xvel = 0.2, Yvel = 0.0;
GLfloat Xmin = -4.0, Xmax = 4.0;
GLfloat Ymin = -3.8, Ymax = 4.0;
GLfloat G = -0.1;

static GLuint make_ball(void) {
	GLuint	list;
	GLfloat a, b;
	GLfloat da = 18.0, db = 18.0;
	GLfloat radius = 1.0;
	GLuint	color;
	GLfloat x, y, z;

	list = glGenLists(1);

	glNewList(list, GL_COMPILE);

	color = 0;
	for(a = -90.0; a + da <= 90.0; a += da) {

		glBegin(GL_QUAD_STRIP);
		for(b = 0.0; b <= 360.0; b += db) {

			if(color) {
				glColor3f(RED);
			} else {
				glColor3f(WHITE);
			}

			x = COS(b) * COS(a);
			y = SIN(b) * COS(a);
			z = SIN(a);
			glVertex3f(x, y, z);

			x = radius * COS(b) * COS(a + da);
			y = radius * SIN(b) * COS(a + da);
			z = radius * SIN(a + da);
			glVertex3f(x, y, z);

			color = 1 - color;
		}
		glEnd();
	}

	glEndList();

	return list;
}

static void reshape(int width, int height) {
	glViewport(0, 0, (GLint)width, (GLint)height);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glOrtho(-6.0, 6.0, -6.0, 6.0, -6.0, 6.0);
	glMatrixMode(GL_MODELVIEW);
}

static void draw(void) {
	GLint i;

	glClear(GL_COLOR_BUFFER_BIT);

	glColor3f(CYAN);
	glBegin(GL_LINES);
	for(i = -5; i <= 5; i++) {
		glVertex2i(i, -5);
		glVertex2i(i, 5);
	}
	for(i = -5; i <= 5; i++) {
		glVertex2i(-5, i);
		glVertex2i(5, i);
	}
	for(i = -5; i <= 5; i++) {
		glVertex2i(i, -5);
		glVertex2f(i * 1.15, -5.9);
	}
	glVertex2f(-5.3, -5.35);
	glVertex2f(5.3, -5.35);
	glVertex2f(-5.75, -5.9);
	glVertex2f(5.75, -5.9);
	glEnd();

	glPushMatrix();
	glTranslatef(Xpos, Ypos, 0.0);
	glScalef(2.0, 2.0, 2.0);
	glRotatef(8.0, 0.0, 0.0, 1.0);
	glRotatef(90.0, 1.0, 0.0, 0.0);
	glRotatef(Zrot, 0.0, 0.0, 1.0);

	glCallList(Ball);

	glPopMatrix();

	glFlush();
}

static void idle(void) {
	static float vel0 = -100.0;

	Zrot += Zstep;

	Xpos += Xvel;
	if(Xpos >= Xmax) {
		Xpos  = Xmax;
		Xvel  = -Xvel;
		Zstep = -Zstep;
	}
	if(Xpos <= Xmin) {
		Xpos  = Xmin;
		Xvel  = -Xvel;
		Zstep = -Zstep;
	}
	Ypos += Yvel;
	Yvel += G;
	if(Ypos < Ymin) {
		Ypos = Ymin;
		if(vel0 == -100.0)
			vel0 = fabs(Yvel);
		Yvel = vel0;
	}
}

static void init(void) {
	Ball = make_ball();
	glCullFace(GL_BACK);
	glEnable(GL_CULL_FACE);
	glDisable(GL_DITHER);
	glShadeModel(GL_FLAT);
}

static void tick(MwWidget handle, void* user, void* client) {
	(void)handle;
	(void)user;
	(void)client;

	draw();
	idle();

	MwOpenGLSwapBuffer(opengl);
}

static void resize(MwWidget handle, void* user, void* client) {
	int ww, wh;

	(void)handle;
	(void)user;
	(void)client;

	ww = MwGetInteger(handle, MwNwidth) - 100;
	wh = MwGetInteger(handle, MwNheight) - 100;

	MwVaApply(opengl,
		  MwNwidth, ww,
		  MwNheight, wh,
		  NULL);

	reshape(ww, wh);
}

int main() {
	MwWidget window;

	window = MwVaCreateWidget(MwWindowClass, "main", NULL, 0, 0, 500, 500,
				  MwNtitle, "boing",
				  NULL);
	opengl = MwCreateWidget(MwOpenGLClass, "opengl", window, 50, 50, 400, 400);

	MwOpenGLMakeCurrent(opengl);

	init();
	reshape(400, 400);

	MwAddUserHandler(window, MwNresizeHandler, resize, NULL);
	MwAddUserHandler(window, MwNtickHandler, tick, NULL);

	MwLoop(window);
}