ref: 34bcf237883f8b57201abbb2ec51c1330394f39e
parent: 736749cad809e6c9cfaed8ed35caa33d24f45af7
author: qwx <qwx@sciops.net>
date: Mon Feb 22 18:42:54 EST 2021
3d05: floating point coords, fixes jerkiness
--- a/3d03.c
+++ b/3d03.c
@@ -19,6 +19,7 @@
Cplayer,
Carrow,
Cwall,
+ Cside,
Cend,
};
static Image *col[Cend];
@@ -149,6 +150,8 @@
bottom = rectaddpt(bottom, Pt(pl.x, pl.y));
line(fb, top.min, top.max, 0, 0, 1, col[Cwall], ZP);
line(fb, bottom.min, bottom.max, 0, 0, 1, col[Cwall], ZP);
+ line(fb, top.min, bottom.min, 0, 0, 1, col[Cside], ZP);
+ line(fb, top.max, bottom.max, 0, 0, 1, col[Cside], ZP);
}
static void
@@ -158,6 +161,7 @@
col[Cplayer] = display->white;
col[Carrow] = eallocimage(Rect(0,0,1,1), screen->chan, 1, 0x777777ff);
col[Cwall] = eallocimage(Rect(0,0,1,1), screen->chan, 1, DYellow);
+ col[Cside] = eallocimage(Rect(0,0,1,1), screen->chan, 1, DRed);
}
static void
--- /dev/null
+++ b/3d05.c
@@ -1,0 +1,183 @@
+/* global map + transformed map + perspective,
+ * floating point coordinates */
+
+#include <u.h>
+#include <libc.h>
+#include <thread.h>
+#include <draw.h>
+#include "dat.h"
+#include "fns.h"
+
+enum{+ Hz = 30,
+};
+char *progname = "3d05";
+
+int tdiv = Te3 / Hz;
+
+enum{+ Cbg,
+ Cplayer,
+ Carrow,
+ Cwall,
+ Cside,
+ Cend,
+};
+static Image *col[Cend];
+
+typedef struct Player Player;
+struct Player{+ Foint;
+ double θ;
+};
+static Player player;
+static Fectangle wall;
+
+static void
+forward(void)
+{+ player.x += cos(player.θ);
+ player.y += sin(player.θ);
+}
+
+static void
+backward(void)
+{+ player.x -= cos(player.θ);
+ player.y -= sin(player.θ);
+}
+
+static void
+turnleft(void)
+{+ player.θ -= 0.1;
+}
+
+static void
+turnright(void)
+{+ player.θ += 0.1;
+}
+
+static void
+transleft(void)
+{+ player.x += sin(player.θ);
+ player.y -= cos(player.θ);
+}
+
+static void
+transright(void)
+{+ player.x -= sin(player.θ);
+ player.y += cos(player.θ);
+}
+
+Key keys[] = {+ {'w', forward},+ {'s', backward},+ {'a', turnleft},+ {'d', turnright},+ {'q', transleft},+ {'e', transright},+};
+int nkeys = nelem(keys);
+
+static void
+stepsim(void)
+{+ Key *k;
+
+ for(k=keys; k<keys+nkeys; k++)
+ if(k->down)
+ k->fn();
+}
+
+static void
+render(void)
+{+ Player pl;
+ Fectangle r, wl, rwl;
+ Rectangle top, bottom;
+
+ draw(fb, fb->r, col[Cbg], nil, ZP);
+ wl = wall;
+ pl = player;
+
+ /* absolute map */
+ line(fb, PFt(wl.min), PFt(wl.max), 0, 0, 1, col[Cwall], ZP);
+ ellipse(fb, Pt(pl.x, pl.y), 2, 2, 0, col[Cplayer], ZP);
+ line(fb, Pt(pl.x, pl.y),
+ Pt(pl.x + cos(player.θ) * 15, pl.y + sin(player.θ) * 15),
+ 0, 0, 0, col[Carrow], ZP);
+
+ /* transform vertices relative to player coordinates */
+ wl.min.x -= pl.x;
+ wl.min.y -= pl.y;
+ wl.max.x -= pl.x;
+ wl.max.y -= pl.y;
+ rwl.min.x = wl.min.x * sin(player.θ) - wl.min.y * cos(player.θ);
+ rwl.min.y = wl.min.x * cos(player.θ) + wl.min.y * sin(player.θ); /* now left depth (since camera looks towards -∞ along y axis */
+ rwl.max.x = wl.max.x * sin(player.θ) - wl.max.y * cos(player.θ);
+ rwl.max.y = wl.max.x * cos(player.θ) + wl.max.y * sin(player.θ); /* now right depth */
+ /* offset view */
+ pl.x = 200;
+ pl.y = 50;
+ r.min.x = pl.x - rwl.min.x;
+ r.min.y = pl.y - rwl.min.y;
+ r.max.x = pl.x - rwl.max.x;
+ r.max.y = pl.y - rwl.max.y;
+ line(fb, PFt(r.min), PFt(r.max), 0, 0, 1, col[Cwall], ZP);
+ ellipse(fb, Pt(pl.x, pl.y), 2, 2, 0, col[Cplayer], ZP);
+ line(fb, Pt(pl.x, pl.y),
+ Pt(pl.x + cos(-PI/2) * 15, pl.y + sin(-PI/2) * 15),
+ 0, 0, 0, col[Carrow], ZP);
+
+ /* perspective-transformed map:
+ * just take the transformed wall coordinates and divide by depth */
+ if(rwl.min.y == 0)
+ rwl.min.y = 1;
+ if(rwl.max.y == 0)
+ rwl.max.y = 1;
+ /* length of the wall = 50 (euclidean distance), we divide for smaller viewsize */
+ top.min.x = 50 + (double)rwl.min.x * 50/2 / rwl.min.y;
+ top.max.x = 50 + (double)rwl.max.x * 50/2 / rwl.max.y;
+ top.min.y = 50 + -50 / (double)rwl.min.y;
+ top.max.y = 50 + -50 / (double)rwl.max.y;
+ bottom.min.x = top.min.x;
+ bottom.max.x = top.max.x;
+ bottom.min.y = 50 + 50 / (double)rwl.min.y;
+ bottom.max.y = 50 + 50 / (double)rwl.max.y;
+ /* offset view */
+ pl.x = 300;
+ top = rectaddpt(top, Pt(pl.x, pl.y));
+ bottom = rectaddpt(bottom, Pt(pl.x, pl.y));
+ line(fb, top.min, top.max, 0, 0, 1, col[Cwall], ZP);
+ line(fb, bottom.min, bottom.max, 0, 0, 1, col[Cwall], ZP);
+ line(fb, top.min, bottom.min, 0, 0, 1, col[Cside], ZP);
+ line(fb, top.max, bottom.max, 0, 0, 1, col[Cside], ZP);
+}
+
+static void
+initrender(void)
+{+ col[Cbg] = display->black;
+ col[Cplayer] = display->white;
+ col[Carrow] = eallocimage(Rect(0,0,1,1), screen->chan, 1, 0x777777ff);
+ col[Cwall] = eallocimage(Rect(0,0,1,1), screen->chan, 1, DYellow);
+ col[Cside] = eallocimage(Rect(0,0,1,1), screen->chan, 1, DRed);
+}
+
+static void
+initsim(void)
+{+ wall = (Fectangle){(Foint){70, 20}, (Foint){70, 70}};+ player = (Player){(Foint){50, 50}, 0};+}
+
+void
+threadmain(int, char**)
+{+ sysinit(initrender, initsim, render, stepsim);
+ sim();
+}
--- a/dat.h
+++ b/dat.h
@@ -1,5 +1,6 @@
typedef struct Key Key;
typedef struct Foint Foint;
+typedef struct Fectangle Fectangle;
enum{Te9 = 1000000000,
@@ -22,6 +23,10 @@
struct Foint{double x;
double y;
+};
+struct Fectangle{+ Foint min;
+ Foint max;
};
extern char *progname;
--- a/drw.c
+++ b/drw.c
@@ -20,6 +20,18 @@
return i;
}
+Point
+PFt(Foint p)
+{+ return (Point){p.x, p.y};+}
+
+Rectangle
+RFect(Fectangle r)
+{+ return (Rectangle){PFt(r.min), PFt(r.max)};+}
+
void
updatedraw(void)
{--- a/fns.h
+++ b/fns.h
@@ -2,6 +2,8 @@
void sim(void);
void sysinit(void (*)(void), void (*)(void), void (*)(void), void (*)(void));
Image* eallocimage(Rectangle, ulong, int, ulong);
+Point PFt(Foint);
+Rectangle RFect(Fectangle);
void updatedraw(void);
void redraw(void);
void resetdraw(void);
--- a/mkfile
+++ b/mkfile
@@ -4,6 +4,7 @@
3d02\
3d03\
3d04\
+ 3d05\
OFILES=\
drw.$O\