initial push

9ray.c

@@ -0,0 +1,110 @@
+#include "vec3.h"
+#include "ray.h"
+
+#include <draw.h>
+#include <event.h>
+
+
+void
+eresized(int new)
+{
+	if(new&& getwindow(display, Refnone) < 0)
+		sysfatal("can't reattach to window");
+}
+
+
+double 
+hit_sphere(vec3 centr, double rad, ray r)
+{
+	vec3 oc = vecsub(r.origin, centr);
+	double a = length_sq(r.direction);
+	double h_b = dot(oc, r.direction);
+	double c = length_sq(oc) - rad*rad;
+	double dis = h_b*h_b - a*c;
+
+	if (dis < 0) {
+		return -1.0;
+	} else {
+		return (-h_b - sqrt(dis) ) / a;
+	}
+}
+
+vec3
+ray_color(ray r)
+{
+	double t = hit_sphere(point3(0,0,-1), 0.5, r);
+	if (t > 0.0) {
+		vec3 N = unit_vector(vecsub(at(r, t), point3(0,0,-1)));
+		N.e[0] += 1;
+		N.e[1] += 1;
+		N.e[2] += 1;
+		vec3 col = vecscale(0.5, N);
+		return col;
+	}
+	vec3 u_dir = unit_vector(r.direction);
+	t = 0.5 * (u_dir.e[1] + 1.0);
+	vec3 o = vecadd(vecscale((1.0-t), color(1.0, 1.0, 1.0)), vecscale(t, color(0.5, 0.7, 1.0)));
+	return o;
+}
+
+void
+main(int argc, char* argv[])
+{
+	USED(argc, argv);
+	
+	Mouse m;
+	Image *color;
+	Point min, max;
+	int i, j;
+	unsigned int ir, ig, ib, rgb;
+	double u, v;
+
+	// Camera
+	vec3 llc = {-2.0, -1.0, -1.0};
+	vec3 hor = {4.0, 0.0, 0.0};
+	vec3 ver = {0.0, 2.0, 0.0};
+	vec3 ori = {0.0, 0.0, 0.0};
+	vec3 dir = {0.0, 0.0, 0.0};
+
+	ray r;
+	r.origin = ori;
+	r.direction = dir;
+
+	initdraw(0, 0, "Plan9 Raytracer");
+	eresized(0);
+	einit(Emouse);
+
+	min = screen->r.min;
+	max = screen->r.max;
+
+	for(j = max.y; j >= min.y; --j)
+	{
+		for(i = min.x; i < max.x; ++i)
+		{
+			u = (double)(i - min.x)/(double)(max.x - min.x);
+			v = (double)(j - min.y)/(double)(max.y - min.y);
+
+			r.origin = ori;
+			r.direction = vecsub(vecadd(vecadd(llc, vecscale(u,hor)), vecscale(v,ver)), ori);
+			vec3 rc = ray_color(r);
+			
+			ir = (unsigned char)255.99*rc.e[0];
+			ig = (unsigned char)255.99*rc.e[1];
+			ib = (unsigned char)255.99*rc.e[2];
+
+			rgb = ((ir & 0xFF) << 24) + ((ig & 0xFF) << 16) + ((ib & 0xFF) << 8) + (255 & 0xFF);
+			color = allocimage(display, Rect(0,0,1,1), RGBA32, 1, rgb);
+			draw(screen,  Rect(i, j, i+1, j+1), color, nil, ZP);
+			freeimage(color);
+		}
+	}
+	flushimage(display, Refnone);
+
+
+	/* Main loop */
+	for(;;) {
+		m = emouse();
+		if(m.buttons & 4)
+			break;
+	}
+}

README.md

@@ -1,2 +1,3 @@
-# 9ray
+This is a raytracer implemented from the book [Ray Tracing In One Weekend](https://raytracing.github.io/books/RayTracingInOneWeekend.html) for the plan9 operating system.
 
+It uses the plan9 dialect of C as well as the plan9 make system

mkfile

@@ -0,0 +1,15 @@
+</$objtype/mkfile
+
+TARG=9ray
+
+OFILES=\
+	9ray.$O\
+
+HFILES=\
+	vec3.h\
+	ray.h\
+	hittable.h\
+	sphere.h\
+
+BIN=/usr/$user/bin/$objtype
+</sys/src/cmd/mkone

ray.h

@@ -0,0 +1,19 @@
+#ifndef RAY_H
+#define RAY_H
+
+#include "vec3.h"
+
+typedef struct ray ray;
+struct ray 
+{
+	vec3 origin;
+	vec3 direction;
+};
+
+inline vec3
+at(ray r, double t)
+{
+	return vecadd(r.origin, vecscale(t, r.direction));
+}
+
+#endif

vec3.h

@@ -0,0 +1,91 @@
+#ifndef VEC3_H
+#define VEC3_H
+
+#include <u.h>
+#include <libc.h>
+
+typedef struct vec3 vec3;
+struct vec3
+{
+	double e[3];
+};
+
+
+inline double
+length_sq(vec3 v)
+{
+	return v.e[0]*v.e[0] + v.e[1]*v.e[1] + v.e[2]*v.e[2];
+}
+
+inline double
+length(vec3 v)
+{
+	return sqrt(length_sq(v));
+}
+
+inline vec3 
+vecscale(double t, vec3 v) 
+{
+	vec3 o = {t*v.e[0], t*v.e[1], t*v.e[2]};
+	return o;
+}
+
+inline vec3
+vecadd(vec3 v1, vec3 v2)
+{
+	vec3 o = {v1.e[0] + v2.e[0], v1.e[1] + v2.e[1], v1.e[2] + v2.e[2]};
+	return o;
+}
+
+
+inline vec3
+vecsub(vec3 v1, vec3 v2)
+{
+	vec3 o = {v1.e[0] - v2.e[0], v1.e[1] - v2.e[1], v1.e[2] - v2.e[2]};
+	return o;
+}
+
+inline vec3 
+vecmul(vec3 v1, vec3 v2)
+{
+	vec3 o = {v1.e[0] * v2.e[0], v1.e[1] * v2.e[1], v1.e[2] * v2.e[2]};
+	return o;
+}
+
+inline double
+dot(vec3 u, vec3 v)
+{
+	return u.e[0] * v.e[0] + u.e[1] * v.e[1] + u.e[2] * v.e[2];
+}
+
+inline vec3
+cross(vec3 u, vec3 v)
+{
+	vec3 o = {(u.e[1] * v.e[2] - u.e[2] * v.e[1]),
+				(u.e[2] * v.e[0] - u.e[0] * v.e[2]),
+				(u.e[0] * v.e[1] - u.e[1] * v.e[0])};
+	return o;
+}
+
+inline vec3 
+unit_vector(vec3 v) 
+{
+	double len = length(v);
+	return vecscale((1/len), v);
+}
+
+inline vec3
+color(double r, double g, double b)
+{
+	vec3 o = {r, g, b};
+	return o;
+}
+
+inline vec3
+point3(double x, double y, double z)
+{
+	vec3 o = color(x, y, z);
+	return o;
+}
+
+#endif