/*
    Copyright 2012 Wolfgang Thaller.

    This file is part of Retro68.

    Retro68 is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    Retro68 is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with Retro68.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifdef __APPLE__
#include <Carbon/Carbon.h>
#include <ApplicationServices/ApplicationServices.h>
#else

#ifdef TARGET_API_MAC_CARBON
#include <math.h>
#include <Carbon.h>
#else
#include <Quickdraw.h>
#include <MacMemory.h>
#include <Sound.h>
#include <Events.h>
#include <Fonts.h>
#include <NumberFormatting.h>
#endif

#endif

#include "fixed.h"

#include <cmath>
#include <algorithm>
#include <cstdlib>
#include <cstring>
#include <vector>
#include <cstdio>

using std::sqrt;
using std::floor;



inline int floor_to_int(float f)
{
    return static_cast<int>(std::floor(f));
}

template<class T>
class vec3
{
public:
    T x,y,z;
    vec3(T x, T y, T z) : x(x), y(y), z(z) {}
    vec3() : x(0), y(0), z(0) {}
    
    vec3<T> operator+(const vec3<T>& other) const { return vec3(x + other.x, y + other.y, z + other.z); }
    vec3<T> operator-(const vec3<T>& other) const { return vec3(x - other.x, y - other.y, z - other.z); }
    vec3<T> operator*(T a) const { return vec3(x*a, y*a, z*a); }
    
    T length() const { return sqrt(x*x + y*y + z*z); }
    T operator*(const vec3<T>& other) const { return x*other.x + y*other.y + z*other.z; }
    
#if 1
    vec3<T> normalize() const { 
        T l = length();
        //if(l == 0)
        //    return *this;
        //else
            return (*this) * (T(1) / l);
    }
#else
    vec3<T> normalize() const { 
        T l = length();
        if(l == 0)
            return *this;
        else
            return vec3<T>(x/l, y/l, z/l);
    }
#endif
};

template<class T>
bool hitSphere(vec3<T> p0, vec3<T> dir, T& t)
{
    const vec3<T> center(0.0f, 1.0f, -6.0f);
    const T r = 2.0f;
    vec3<T> p0c(p0 - center);
    
    /*
    (x-xc)^2 + (y-yc)^2 + (z-zc)^2 = r^2;
    (x0c + dx * t)^2 + (y0c + dy * t)^2 + (z0c + dz * t)^2 = r^2;
    x0c^2 + 2*x0c*dx*t + dx^2*t^2 + y0c^2 + 2*y0c*dy*t + dy^2*t^2 + z0c^2 + 2 * z0c*dz*t + dz^2*t^2 = r^2
    
    (dx^2 + dy^2 + dz^2)*t^2 + (2*x0c*dx + 2*y0c&dy + 2*z0c*dz) * t + x0c^2+y0c^2+z0c^2-r^2
    */
    T a = dir*dir;
    T b = 2*(p0c*dir);
    T c = p0c*p0c - r*r;
    
    T D = b*b - 4 * a * c;
    
    if(D >= 0)
    {
        t = (-b - sqrt(D)) / (2*a);
        return t >= 0;
    }
    return false;
}


template<class T>
T ray(int n, vec3<T> p0, vec3<T> dir)
{
#if 1
    static const vec3<T> light = vec3<T>(-2,4,3).normalize();
    
    if(1){
        const vec3<T> center(0.0f, 1.0f, -6.0f);
        const T r = 2.0f;
        vec3<T> p0c(p0 - center);
        
        /*
        (x-xc)^2 + (y-yc)^2 + (z-zc)^2 = r^2;
        (x0c + dx * t)^2 + (y0c + dy * t)^2 + (z0c + dz * t)^2 = r^2;
        x0c^2 + 2*x0c*dx*t + dx^2*t^2 + y0c^2 + 2*y0c*dy*t + dy^2*t^2 + z0c^2 + 2 * z0c*dz*t + dz^2*t^2 = r^2
        
        (dx^2 + dy^2 + dz^2)*t^2 + (2*x0c*dx + 2*y0c&dy + 2*z0c*dz) * t + x0c^2+y0c^2+z0c^2-r^2
        */
        T a = dir*dir;
        T b = 2*(p0c*dir);
        T c = p0c*p0c - r*r;
        
        T D = b*b - 4 * a * c;
        
        if(D >= 0)
        {
            T t = (-b -  sqrt(D)) / (2*a);
            if(t > 0)
            {
                vec3<T> p = p0 + dir * t;
                
                vec3<T> dir2 = (p - center) * (T(1)/r);
                
                T l = dir2*dir;
                
                T reflected;
                if(n)
                    reflected = ray(n-1, p, dir - dir2*(l*2));
                else
                    reflected = 0.0f;
                
                
                T lambert = dir2 * light;
                
                return T(0.2f) + T(0.4f) * std::max(T(0),lambert) + T(0.4f) * reflected;
            }
        }
    }

    if(dir.y < 0)
    {
        T t = (T(-1.5f) - p0.y) / dir.y;
        vec3<T> p = p0 + dir*t;
        
        T color;
        if( (floor_to_int(p.x)
            + floor_to_int(p.z)) % 2 )
            color = 0.8f;
        else
            color = 0.1f;
        
        T ts;
        if(hitSphere(p, light, ts))
            color *= T(0.2f);
        
        return std::min(T(1), color + T(0.5f) * ray(n-1, p,vec3<T>(dir.x, -dir.y, dir.z)));
    }
#endif
    return std::max(T(0), dir.y * T(0.3f));
}

typedef fixed numtype;


template<class T>
struct rand1
{
    static T get()
    {
        return T(std::rand()) / T(32767.0f * 65536.0f);
    }
};

template<>
struct rand1<fixed>
{
    static fixed get()
    {
        return fixed(std::rand() >> 15, fixed::raw());
    }
};

int main()
{
    WindowPtr win;
#if !TARGET_API_MAC_CARBON
    InitGraf(&qd.thePort);
    InitFonts();
    InitWindows();
    InitMenus();

    Rect r = qd.screenBits.bounds;
#else
    BitMap bm;
    GetQDGlobalsScreenBits(&bm);
    Rect r = bm.bounds;
#endif    
    SetRect(&r, r.left + 5, r.top + 45, r.right - 5, r.bottom -5);
    win = NewWindow(NULL, &r, "\pRaytracer (C++ Version)", true, 0, (WindowPtr)-1, false, 0);
    
#if !TARGET_API_MAC_CARBON    
    SetPort(win);
    r = win->portRect;
#else
    SetPortWindowPort(win);
    GetPortBounds(GetWindowPort(win), &r);
#endif
    EraseRect(&r);
    numtype accum = 0.0f;
    short cx = r.right /2;
    short cy = r.bottom / 2;
    
    long startTime = TickCount();
    std::vector<numtype> accumV(r.right);
    BitMap line;
    std::vector<unsigned char> bits(((r.right + 31) / 8) & ~0x3);
    SetRect(&line.bounds, 0,0,r.right,1);
    line.rowBytes = bits.size();
    line.baseAddr = (char*)(&bits[0]);
    
    numtype preRandoms[29*31];
    for(int i = 0; i < 29*31; i++)
    {
        numtype thresh = rand1<numtype>::get();
        thresh = numtype(0.5f) + numtype(0.4f) * (thresh - numtype(0.5f));
        preRandoms[i] = thresh;
    }
    int randIdx = 0;

    for(int y = 0; y < r.bottom; y++)
    {
        std::fill(bits.begin(),bits.end(), 0);
        for(int x = 0; x < r.right; x++)
        {
            numtype pixel;
            
            // cam = (0,0,0)
            // ray = t * (x-r.right/2, - (y-r.bottom/2), -1)
            // plane: y = -2
            pixel = ray(1,vec3<numtype>(),vec3<numtype>(numtype(x-cx)/numtype(cx),-numtype(y-cy)/numtype(cx),-1).normalize());

            numtype thresh = preRandoms[randIdx++];
            if(randIdx == 29*31)
                randIdx = 0;
            
            accum += pixel;
            accum += accumV[x];
            if(accum >= thresh)
                accum -= 1;
            else
            {
                //MoveTo(x,y);
                //Line(0,0);
                bits[x / 8] |= (0x80 >> (x%8));
            }
            accumV[x] = accum = accum / numtype(2);            
        }
        Rect r2;
        SetRect(&r2,0,y,r.right,y+1);
#if TARGET_API_MAC_CARBON
        CopyBits(&line, GetPortBitMapForCopyBits(GetWindowPort(win)), &line.bounds, &r2, srcCopy, NULL);
#else
        CopyBits(&line, &win->portBits, &line.bounds, &r2, srcCopy, NULL);
#endif
        if(Button())
            return 0;
#if TARGET_API_MAC_CARBON
        QDFlushPortBuffer(GetWindowPort(win),NULL);
#endif
    }
    long endTime = TickCount();
    
    char buf[256];
    unsigned char* pstr = (unsigned char*)buf;
    std::sprintf(buf+1, "pps = %d %ld %ld %ld %ld", (int)( (long)r.right * r.bottom * 60 / (endTime - startTime) ),
                 fixed::nMul, fixed::nIMul, fixed::nDiv, fixed::nSqrt);
    buf[0] = std::strlen(buf+1);
    
    SetRect(&r, 10, 10, 10 + StringWidth(pstr) + 10, 30);
    PaintRect(&r);
    PenMode(patXor);
    FrameRect(&r);
    MoveTo(15,25);
    TextMode(srcBic);
    DrawString(pstr);
#if TARGET_API_MAC_CARBON
    QDFlushPortBuffer(GetWindowPort(win),NULL);
#endif
    
    while(!Button())
        ;
    FlushEvents(everyEvent, -1);
    return 0;
}