Retro68/Samples/Raytracer/raytracer.c
2015-10-07 00:03:28 +02:00

287 lines
6.2 KiB
C

/*
Copyright 2014 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 <math.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <stdio.h>
pascal /* <- pascal calling convention, for no reason in particular except to test the comppiler */
bool hitSphere(float x0, float y0, float z0, float dx, float dy, float dz, float *t)
{
const float xc = 0.0f, yc = 0.0f, zc = -6.0f, r = 1.0f;
float x0c = x0 - xc;
float y0c = y0 - yc;
float z0c = z0 - zc;
/*
(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
*/
float a = dx*dx + dy*dy + dz*dz;
float b = 2*(x0c*dx + y0c*dy + z0c*dz);
float c = x0c*x0c + y0c*y0c + z0c*z0c -r*r;
float D = b*b - 4 * a * c;
if(D >= 0)
{
*t = (-b - sqrtf(D)) / (2*a);
return *t >= 0;
}
return false;
}
const float lx = -2, ly = 4, lz = 3;
float lenl;
float lxn, lyn, lzn;
float ray(int n, float x0, float y0, float z0, float dx, float dy, float dz)
{
{
const float xc = 0.0f, yc = 0.0f, zc = -6.0f, r = 1.0f;
float x0c = x0 - xc;
float y0c = y0 - yc;
float z0c = z0 - zc;
/*
(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
*/
float a = dx*dx + dy*dy + dz*dz;
float b = 2*(x0c*dx + y0c*dy + z0c*dz);
float c = x0c*x0c + y0c*y0c + z0c*z0c -r*r;
float D = b*b - 4 * a * c;
if(D >= 0)
{
float t = (-b - sqrtf(D)) / (2*a);
if(t > 0)
{
float x = x0 + dx * t;
float y = y0 + dy * t;
float z = z0 + dz * t;
float dx2 = x - xc;
float dy2 = y - yc;
float dz2 = z - zc;
float l = dx2 * dx + dy2 * dy + dz2 * dz;
l *= 2;
float reflected;
if(n)
reflected = ray(n-1, x,y,z, dx - l*dx2, dy - l*dy2, dz - l*dz2);
else
reflected = 0.0f;
float lambert = dx2 * lxn + dy2 * lyn + dz2 * lzn;
if(lambert < 0.0f)
lambert = 0.0f;
return 0.2f + 0.4f * lambert + 0.4f * reflected;
}
}
}
if(dy < 0)
{
float t = (-1.5f - y0) / dy;
float x = x0 + dx * t;
float z = z0 + dz * t;
float color;
if( ((int)( floorf(x) )
+ (int)( floorf(z) )) % 2 )
color = 0.8f;
else
color = 0.1f;
float ts;
if(hitSphere(x,-1.5f,z, lxn, lyn, lzn, &ts))
color *= 0.2f;
float v = color + 0.5f * ray(n-1, x,-1.5f,z,dx,-dy,dz);
if(v > 1.0f)
return 1.0f;
else
return v;
}
float v = dy * 0.3f;
if(v < 0.0f)
return 0.0f;
else
return v;
}
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);
float accum = 0.0f;
short cx = r.right /2;
short cy = r.bottom / 2;
int x,y;
lenl = 1.0f / sqrtf(lx*lx + ly*ly + lz*lz);
lxn = lx*lenl, lyn = ly*lenl, lzn = lz*lenl;
long startTime = TickCount();
float *accumV = calloc(sizeof(float), r.right);
for(y = 0; y < r.bottom; y++)
{
for(x = 0; x < r.right; x++)
{
float pixel;
// cam = (0,0,0)
// ray = t * (x-r.right/2, - (y-r.bottom/2), -1)
// plane: y = -2
float dx = x - cx;
float dy = - (y - cy);
float dz = -cx;
float n1 = 1.0f / sqrtf(dx*dx + dy*dy + dz*dz);
pixel = ray(1,0,0,0,n1*dx,n1*dy,n1*dz);
#if 0
accum += pixel;
if(accum >= 0.5f)
accum -= 1.0f;
else
{
MoveTo(x,y);
Line(0,0);
}
#elif 0
accum += pixel;
accum += accumV[x];
if(accum >= 0.5f)
accum -= 1.0f;
else
{
MoveTo(x,y);
Line(0,0);
}
accumV[x] = accum = accum / 2;
#elif 0
//if(pixel < Random() / 32767.0)
if(pixel < (float)std::rand() / (32767.0f * 65536.0f))
{
MoveTo(x,y);
Line(0,0);
}
#else
float thresh = (float)rand() / (32767.0f * 65536.0f);
thresh = 0.5f + 0.4f * (thresh - 0.5f);
accum += pixel;
accum += accumV[x];
if(accum >= thresh)
accum -= 1.0f;
else
{
MoveTo(x,y);
Line(0,0);
}
accumV[x] = accum = accum / 2;
#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;
sprintf(buf+1, "pps = %d", (int)( (float)r.right * r.bottom / (endTime - startTime) * 60.0f ));
buf[0] = 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;
}