ref: 736749cad809e6c9cfaed8ed35caa33d24f45af7
parent: f28761707705822dcbc33b4de801d5d41f92331c
author: qwx <qwx@sciops.net>
date: Mon Feb 22 18:21:10 EST 2021
3d0[34]: perspective sort of
--- a/3d02.c
+++ b/3d02.c
@@ -138,8 +138,7 @@
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);
/* offset to third view */
- pl.x = 400;
- pl.y = 50;
+ pl.x = 300;
rwl.min.x = pl.x - rwl.min.x;
rwl.min.y = pl.y - rwl.min.y;
rwl.max.x = pl.x - rwl.max.x;
--- /dev/null
+++ b/3d03.c
@@ -1,0 +1,175 @@
+/* global map + transformed map + perspective */
+
+#include <u.h>
+#include <libc.h>
+#include <thread.h>
+#include <draw.h>
+#include "dat.h"
+#include "fns.h"
+
+enum{+ Hz = 30,
+};
+char *progname = "3d03";
+
+int tdiv = Te3 / Hz;
+
+enum{+ Cbg,
+ Cplayer,
+ Carrow,
+ Cwall,
+ Cend,
+};
+static Image *col[Cend];
+
+typedef struct Player Player;
+struct Player{+ Foint;
+ double θ;
+};
+static Player player;
+static Rectangle 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;
+ Rectangle r, wl, rwl, top, bottom;
+
+ draw(fb, fb->r, col[Cbg], nil, ZP);
+ wl = wall;
+ pl = player;
+
+ /* absolute map */
+ line(fb, wl.min, 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, r.min, 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.max.y == 0)
+ return;
+ /* 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);
+}
+
+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);
+}
+
+static void
+initsim(void)
+{+ wall = Rect(70, 20, 70, 70);
+ player = (Player){(Foint){50, 50}, 0};+}
+
+void
+threadmain(int, char**)
+{+ sysinit(initrender, initsim, render, stepsim);
+ sim();
+}
--- /dev/null
+++ b/3d04.c
@@ -1,0 +1,170 @@
+/* global map + transformed map + perspective */
+
+#include <u.h>
+#include <libc.h>
+#include <thread.h>
+#include <draw.h>
+#include "dat.h"
+#include "fns.h"
+
+enum{+ Hz = 30,
+};
+char *progname = "3d04";
+
+int tdiv = Te3 / Hz;
+
+enum{+ Cbg,
+ Cplayer,
+ Carrow,
+ Cwall,
+ Cend,
+};
+static Image *col[Cend];
+
+typedef struct Player Player;
+struct Player{+ Foint;
+ double θ;
+};
+static Player player;
+static Rectangle 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;
+ Rectangle r, wl, rwl, top;
+
+ draw(fb, fb->r, col[Cbg], nil, ZP);
+ wl = wall;
+ pl = player;
+
+ /* absolute map */
+ line(fb, wl.min, 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, r.min, 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.max.y == 0)
+ return;
+ /* offset view */
+ pl.x = 300;
+ /* 50: length of the wall (euclidean distance) */
+ top.min.x = 50/2 * (double)rwl.min.x / rwl.min.y;
+ top.min.y = (double)top.min.x / rwl.min.y;
+ top.max.x = 50/2 * (double)rwl.max.x / rwl.max.y;
+ top.max.y = (double)top.min.x / rwl.max.y;
+ r = rectaddpt(top, Pt(pl.x, pl.y));
+ line(fb, r.min, r.max, 0, 0, 1, col[Cwall], ZP);
+ line(fb, Pt(r.min.x, 100-r.min.y), Pt(r.max.x, 100-r.max.y), 0, 0, 1, col[Cwall], 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);
+}
+
+static void
+initsim(void)
+{+ wall = Rect(70, 20, 70, 70);
+ player = (Player){(Foint){50, 50}, 0};+}
+
+void
+threadmain(int, char**)
+{+ sysinit(initrender, initsim, render, stepsim);
+ sim();
+}
--- a/mkfile
+++ b/mkfile
@@ -2,6 +2,8 @@
TARG=\
3d01\
3d02\
+ 3d03\
+ 3d04\
OFILES=\
drw.$O\