stew

commit 681efd14212b569fe82a1ac492d36cea2a9585a5
parent 4dfcc258692340d2633304fae82dee14af880296
Author: glenda <glenda@device>
Date:   Sun, 30 Oct 2022 22:16:44 +0000

cubes: triangular

Diffstat:
A
src/cubes/triangle.c
 | 
135
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 135 insertions(+), 0 deletions(-)
diff --git a/src/cubes/triangle.c b/src/cubes/triangle.c
@@ -0,0 +1,135 @@
+#include <u.h>
+#include <libc.h>
+#include <draw.h>
+#include <event.h>
+#include <geometry.h>
+
+#define CSWidth 640
+#define CSHeight 640
+#define CSSize (CSWidth * CSHeight)
+
+u32int imgbuf[CSSize];
+int m[3][3];
+Point pts[3];
+Image *img;
+vlong n;
+char *s;
+
+void
+triangle(int i)
+{
+	int X = i % CSWidth;
+	int Y = i / CSWidth;
+
+	#define l(m)     (m[0] * X + m[1] * Y + m[2])
+	#define istriag  ((l(m[0]) > 0) && (l(m[1]) > 0) && (l(m[2]) > 0))
+	#define isline   ((l(m[0]) <= 10) || (l(m[1]) <= 10) || (l(m[2]) <= 10))
+
+	imgbuf[i] = istriag ? 0x00ff7f00 : (imgbuf[i] / 2) &0xffff0000;
+
+
+	#undef l
+	#undef istriag
+	#undef isline
+}
+
+void
+vrender(void)
+{
+	int i;
+	for (i = 0; i < CSSize; i++) triangle(i);
+}
+
+void
+redraw(Image *)
+{
+	draw(screen, screen->r, display->white, nil, ZP);
+	draw(screen, screen->r, img, nil, ZP);
+
+	string(screen, screen->r.min, display->white, ZP, font, s);
+}
+
+void
+eresized(int new)
+{
+	if(new && getwindow(display, Refnone) < 0)
+		fprint(2,"can't reattach to window");
+	redraw(screen);
+}
+
+void
+randomize_pts(void)
+{
+	pts[0] = Pt(nrand(640), nrand(640));
+	pts[1] = Pt(nrand(640), nrand(640));
+	pts[2] = Pt(nrand(640), nrand(640));
+}
+
+void
+pts2linear(void)
+{
+#define lconv(m, u, w) \
+	m[0] = w.y - u.y, \
+	m[1] = u.x - w.x, \
+	m[2] = - m[0] * u.x - m[1] * u.y
+
+	lconv(m[0], pts[0], pts[1]);
+	lconv(m[1], pts[1], pts[2]);
+	lconv(m[2], pts[2], pts[0]);
+
+#undef lconv
+}
+
+void
+normalize(void)
+{
+#define l(m, u)     (m[0] * u.x + m[1] * u.y + m[2])
+#define invert(m) m[0] = -m[0], m[1] = -m[1], m[2] = -m[2];
+
+	if (l(m[0], pts[2]) < 0) invert(m[0]);
+	if (l(m[1], pts[0]) < 0) invert(m[1]);
+	if (l(m[2], pts[1]) < 0) invert(m[2]);
+
+#undef l
+#undef invert
+}
+
+
+void
+main(void)
+{
+
+	srand(nsec());
+
+	n = nsec();
+	vrender();
+	n = nsec() - n;
+	s = smprint("render time %lld nsec", n);
+	initdraw(nil, 0, "cubes");
+	img = allocimage(display, Rect(0, 0, CSWidth, CSHeight), XRGB32, 0, DRed);
+
+	randomize_pts();
+	pts2linear();
+	normalize();
+	n = nsec(); vrender(); n = nsec() - n;
+	loadimage(img, img->r, (uchar *)imgbuf, CSSize * 4);
+	s = smprint("render time %lld nsec", n);
+	redraw(img);
+
+	Event e;
+	einit(Emouse);
+	int timer = etimer(0, 125);
+	for(;;) {
+		int key = event(&e);
+		if (key == timer) {
+
+			randomize_pts();
+			pts2linear();
+			normalize();
+			n = nsec(); vrender(); n = nsec() - n;
+			loadimage(img, img->r, (uchar *)imgbuf, CSSize * 4);
+			free(s); s = smprint("render time %lld nsec", n);
+			redraw(img);
+		}
+	}
+}