ref: f28761707705822dcbc33b4de801d5d41f92331c
parent: c814d360cadf2e3b9fb2c6572b34dae6a77aa06c
author: qwx <qwx@sciops.net>
date: Mon Feb 22 11:33:29 EST 2021
3d02: transformed view from player camera
--- a/3d01.c
+++ b/3d01.c
@@ -1,3 +1,5 @@
+/* absolute basic: global 2d topdown map view */
+
#include <u.h>
#include <libc.h>
#include <thread.h>
@@ -89,7 +91,6 @@
k->fn();
}
-/* absolute map: global 2d topdown view */
static void
render(void)
{--- /dev/null
+++ b/3d02.c
@@ -1,0 +1,175 @@
+/* global map + transformed map
+ * like in opengl, the player's position on the transformed map
+ * is fixed, and the world around it moves.
+ */
+
+#include <u.h>
+#include <libc.h>
+#include <thread.h>
+#include <draw.h>
+#include "dat.h"
+#include "fns.h"
+
+enum{+ Hz = 30,
+};
+char *progname = "3d02";
+
+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 wl, rwl;
+
+ 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;
+ /* ... but don't rotate */
+ rwl = wl;
+ /* offset to second view */
+ pl.x = 200;
+ pl.y = 50;
+ rwl.min.x = pl.x - rwl.min.x;
+ rwl.min.y = pl.y - rwl.min.y;
+ rwl.max.x = pl.x - rwl.max.x;
+ rwl.max.y = pl.y - rwl.max.y;
+ line(fb, rwl.min, rwl.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), /* neg since y is flipped */
+ 0, 0, 0, col[Carrow], ZP);
+
+ /* same, but do rotate */
+ rwl = wl;
+ 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);
+ 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;
+ rwl.min.x = pl.x - rwl.min.x;
+ rwl.min.y = pl.y - rwl.min.y;
+ rwl.max.x = pl.x - rwl.max.x;
+ rwl.max.y = pl.y - rwl.max.y;
+ line(fb, rwl.min, rwl.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);
+}
+
+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
@@ -1,6 +1,7 @@
</$objtype/mkfile
TARG=\
3d01\
+ 3d02\
OFILES=\
drw.$O\