/*
 * EffecTV - Realtime Digital Video Effector
 * Copyright (C) 2001-2003 FUKUCHI Kentaro
 *
 * VertigoTV - Alpha blending with zoomed and rotated images.
 * Copyright (C) 2001-2002 FUKUCHI Kentaro
 *
 */

#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "EffecTV.h"
#include "utils.h"

static int start(void);
static int stop(void);
static int draw(RGB32 *src, RGB32 *dest);
static int event();

static char *effectname = "VertigoTV";
static int state = 0;
static RGB32 *buffer;
static RGB32 *current_buffer, *alt_buffer;
static int dx, dy;
static int sx, sy;
static double phase = 0.0;
static double phase_increment = 0.02;
static double zoomrate = 1.01;

static void setParams()
{
	double vx, vy;
	double t;
	double x, y;
	double dizz;

	dizz = sin(phase) * 10 + sin(phase*1.9+5) * 5;

	x = video_width / 2;
	y = video_height / 2;
	t = (x*x + y*y) * zoomrate;
	if(video_width > video_height) {
		if(dizz >= 0) {
			if(dizz > x) dizz = x;
			vx = (x*(x-dizz) + y*y) / t;
		} else {
			if(dizz < -x) dizz = -x;
			vx = (x*(x+dizz) + y*y) / t;
		}
		vy = (dizz*y) / t;
	} else {
		if(dizz >= 0) {
			if(dizz > y) dizz = y;
			vx = (x*x + y*(y-dizz)) / t;
		} else {
			if(dizz < -y) dizz = -y;
			vx = (x*x + y*(y+dizz)) / t;
		}
		vy = (dizz*x) / t;
	}
	dx = vx * 65536;
	dy = vy * 65536;
	sx = (-vx * x + vy * y + x + cos(phase*5) * 2) * 65536;
	sy = (-vx * y - vy * x + y + sin(phase*6) * 2) * 65536;

	phase += phase_increment;
	if(phase > 5700000) phase = 0;
}

effect *dizzyRegister()
{
	effect *entry;
	
//	sharedbuffer_reset();
	buffer = (RGB32 *)malloc(video_area * 2 * PIXEL_SIZE);
	if(buffer == NULL) {
		return NULL;
	}

	entry = (effect *)malloc(sizeof(effect));
	if(entry == NULL) {
		return NULL;
	}
	
	entry->name = effectname;
	entry->start = start;
	entry->stop = stop;
	entry->draw = draw;
	entry->event = event;

	return entry;
}

static int start()
{
	memset(buffer, 0, video_area * 2 * PIXEL_SIZE);
	current_buffer = buffer;
	alt_buffer = buffer + video_area;
	phase = 0;

	state = 1;
	return 0;
}

static int stop()
{
	state = 0;
	return 0;
}

static int draw(RGB32 *src, RGB32 *dest)
{
	RGB32 *p;
	RGB32 v;
	int x, y;
	int ox, oy;
	int i;

	setParams();
	p = alt_buffer;
	for(y=video_height; y>0; y--) {
		ox = sx;
		oy = sy;
		for(x=video_width; x>0; x--) {
			i = (oy>>16)*video_width + (ox>>16);
			if(i<0) i = 0;
			if(i>=video_area) i = video_area;
			v = current_buffer[i] & 0xfcfcff;
			v = (v * 3) + ((*src++) & 0xfcfcff);
			*p++ = (v>>2);
			ox += dx;
			oy += dy;
		}
		sx -= dy;
		sy += dx;
	}

	memcpy(dest, alt_buffer, video_area*sizeof(RGB32));

	p = current_buffer;
	current_buffer = alt_buffer;
	alt_buffer = p;

	return 0;
}

static int event(SDL_Event *event)
{
	if(event->type == SDL_KEYDOWN) {
		switch(event->key.keysym.sym) {
		case SDLK_SPACE:
			phase = 0.0;
			phase_increment = 0.02;
			zoomrate = 1.01;
			break;

		case SDLK_INSERT:
			phase_increment += 0.01;
			break;

		case SDLK_DELETE:
			phase_increment -= 0.01;
			if(phase_increment < 0.01) {
				phase_increment = 0.01;
			}
			break;

		case SDLK_PAGEUP:
			zoomrate += 0.01;
			if(zoomrate > 1.1) {
				zoomrate = 1.1;
			}
			break;

		case SDLK_PAGEDOWN:
			zoomrate -= 0.01;
			if(zoomrate < 1.01) {
				zoomrate = 1.01;
			}
			break;

		default:
			break;
		}
	}

	return 0;
}