shithub: 3d

Download patch

ref: 7f9460178c58b1eaf0496c3c290380d2159cf471
parent: f28701a4f6b817d1e5b325eb81ed4892ebecacbf
author: qwx <qwx@sciops.net>
date: Wed Mar 17 08:54:39 EDT 2021

3d07: same but using a limited view pasted on the fb

still doesn't work right, not sure the math is correct at all

--- a/3d06.c	Fri Mar 12 06:45:05 2021
+++ b/3d06.c	Wed Mar 17 08:54:39 2021
@@ -11,7 +11,7 @@
 enum{
 	Hz = 30,
 };
-char *progname = "3d05";
+char *progname = "3d06";
 
 int tdiv = Te3 / Hz;
 
--- /dev/null	Sun Oct 31 09:34:01 2021
+++ b/3d07.c	Wed Mar 17 08:54:39 2021
@@ -0,0 +1,225 @@
+/* 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 = "3d07";
+
+int tdiv = Te3 / Hz;
+
+enum{
+	Cbg,
+	Cplayer,
+	Carrow,
+	Cwall,
+	Cside,
+	Cend,
+};
+static Image *col[Cend], *view;
+
+typedef struct Player Player;
+struct Player{
+	Foint;
+	double θ;
+};
+static Player player;
+static Fectangle wall;
+
+static double
+crossprod(Foint a, Foint b)
+{
+	return a.x * b.y - a.y * b.x;	/* = z */
+}
+
+static Foint
+intersect(Foint p0, Foint p1, Foint p2, Foint p3)
+{
+	double x, y, det;
+
+	x = crossprod(p0, p1);
+	y = crossprod(p2, p3);
+	det = crossprod(Ft(p0.x - p1.x, p0.y - p1.y), Ft(p2.x - p3.x, p2.y - p2.y));
+	if(det == 0.0)
+		det = 1e-9;
+	x = crossprod(Ft(x, p0.x - p1.x), Ft(y, p2.x - p3.x)) / det;
+	y = crossprod(Ft(x, p0.y - p1.y), Ft(y, p2.y - p3.y)) / det;
+	return (Foint){x, y};
+}
+
+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;
+	Foint z1, z2;
+	Fectangle wl, rwl;
+	Rectangle r, top, bottom;
+
+	draw(fb, fb->r, col[Cbg], nil, ZP);
+	wl = wall;
+	pl = player;
+
+	r = view->r;
+	/* absolute map */
+	draw(view, view->r, col[Cbg], nil, ZP);
+	line(view, PFt(wl.min), PFt(wl.max), 0, 0, 1, col[Cwall], ZP);
+	ellipse(view, Pt(pl.x, pl.y), 2, 2, 0, col[Cplayer], ZP);
+	line(view, Pt(pl.x, pl.y),
+		Pt(pl.x + cos(player.θ) * 5, pl.y + sin(player.θ) * 5),
+		0, 0, 0, col[Carrow], ZP);
+	draw(fb, r, view, nil, ZP);
+
+	r = rectaddpt(r, Pt(view->r.max.x + 8, 0));
+	/* 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;
+	pl.x = 50;
+	pl.y = 50;
+	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 */
+	top = Rect(50 - rwl.min.x, 50 - rwl.min.y, 50 - rwl.max.x, 50 - rwl.max.y);
+	draw(view, view->r, col[Cbg], nil, ZP);
+	line(view, top.min, top.max, 0, 0, 1, col[Cwall], ZP);
+	ellipse(view, Pt(pl.x, pl.y), 2, 2, 0, col[Cplayer], ZP);
+	line(view, Pt(pl.x, pl.y),
+		Pt(pl.x + cos(-PI/2) * 5, pl.y + sin(-PI/2) * 5),
+		0, 0, 0, col[Carrow], ZP);
+	draw(fb, r, view, nil, ZP);
+
+	r = rectaddpt(r, Pt(view->r.max.x + 8, 0));
+	/* perspective-transformed map:
+	 * just take the transformed wall coordinates and divide by depth */
+	/* first clip line if it crosses the player's viewplane,
+	 * ie. when one of the depth coordinates is negative;
+	 * if both are negative, it is behind the player */
+	if(rwl.min.y <= 0 && rwl.max.y <= 0)
+		return;
+	if(rwl.min.y == 0)
+		rwl.min.y = 1;
+	if(rwl.max.y == 0)
+		rwl.max.y = 1;
+	z1 = intersect(Ft(rwl.min.x, rwl.min.y), Ft(rwl.max.x, rwl.max.y), Ft(-1e-4, 1e-4), Ft(-20, 5));
+	z2 = intersect(Ft(rwl.min.x, rwl.min.y), Ft(rwl.max.x, rwl.max.y), Ft(1e-4, 1e-4), Ft(20, 5));
+	if(rwl.min.y <= 0){
+		if(z1.y > 0)
+			rwl.min.x = z1.x, rwl.min.y = z1.y;
+		else
+			rwl.min.x = z2.x, rwl.min.y = z2.y;
+	}
+	if(rwl.max.y <= 0){
+		if(z1.y > 0)
+			rwl.max.x = z1.x, rwl.max.y = z1.y;
+		else
+			rwl.max.x = z2.x, rwl.max.y = z2.y;
+	}
+	top.min.x = 50 - rwl.min.x * 16 / rwl.min.y;
+	top.max.x = 50 - rwl.max.x * 16 / rwl.max.y;
+	top.min.y = 50 - 50 / rwl.min.y;
+	top.max.y = 50 - 50 / rwl.max.y;
+	bottom.min.x = top.min.x;
+	bottom.max.x = top.max.x;
+	bottom.min.y = 50 + 50 / rwl.min.y;
+	bottom.max.y = 50 + 50 / rwl.max.y;
+	draw(view, view->r, col[Cbg], nil, ZP);
+	line(view, top.min, top.max, 0, 0, 1, col[Cwall], ZP);
+	line(view, bottom.min, bottom.max, 0, 0, 1, col[Cwall], ZP);
+	line(view, top.min, bottom.min, 0, 0, 1, col[Cside], ZP);
+	line(view, top.max, bottom.max, 0, 0, 1, col[Cside], ZP);
+	draw(fb, r, view, nil, 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);
+	view = eallocimage(Rect(0,0,100,110), screen->chan, 1, DBlack);
+}
+
+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/mkfile	Fri Mar 12 06:45:05 2021
+++ b/mkfile	Wed Mar 17 08:54:39 2021
@@ -6,6 +6,7 @@
 	3d04\
 	3d05\
 	3d06\
+	3d07\
 
 OFILES=\
 	drw.$O\