octree

commit 563ba2d1774f8d785977e68883919605b2f610eb
parent 545ff5be825e3fa35ee502e9bc041bca47845825
Author: Pavel Renev <an2qzavok@gmail.com>
Date:   Sun, 21 Mar 2021 21:23:34 +0000

render: add light, finally

Diffstat:
M
render.c
 | 
110
++++++++++++++++++++++++++++++++++++++++++++-----------------------------------

1 file changed, 61 insertions(+), 49 deletions(-)
diff --git a/render.c b/render.c
@@ -5,72 +5,75 @@
 
 #define SQR(X) (X * X)
 
-typedef struct Pixel Pixel;
-typedef struct Dot Dot;
+typedef struct Vect Vect;
 typedef struct Ray Ray;
 typedef struct Sphere Sphere;
 
-struct Pixel {
-	double r;
-	double g;
-	double b;
-};
-
-struct Dot {
+struct Vect {
 	double x;
 	double y;
 	double z;
 };
 
-
 struct Ray {
-	Dot pos;
-	Dot dir;
+	Vect pos;
+	Vect dir;
 };
 
 struct Sphere {
-	Dot pos;
+	Vect pos;
 	double radius;
 };
 
-Pixel Pwhite = {1, 1, 1};
-Pixel Pblack = {0, 0, 0};
-
-Sphere sphere = {{0.5, 0.5, 0}, 0.5};
+Vect Pwhite = {1, 1, 1};
+Vect Pblack = {0, 0, 0};
 
 double
-dotmod(Dot d)
+vectmod(Vect d)
 {
 	return sqrt(SQR(d.x) + SQR(d.y) + SQR(d.z));
 }
 
-Dot
-dotnorm(Dot d)
+Vect
+vectnorm(Vect d)
 {
 	double m;
-	m = dotmod(d);
-	return (Dot){d.x/m, d.y/m, d.z/m};
+	m = vectmod(d);
+	return (Vect){d.x/m, d.y/m, d.z/m};
 }
 
-Dot
-dotxdot(Dot d1, Dot d2)
+Vect
+vectxvect(Vect d1, Vect d2)
 {
-	return (Dot){d1.x * d2.x, d1.y * d2.y, d1.z * d2.z,};
+	return (Vect){d1.x * d2.x, d1.y * d2.y, d1.z * d2.z};
 }
 
-Dot
-adddot(Dot d1, Dot d2)
+
+Vect
+addvect(Vect d1, Vect d2)
 {
-	return (Dot){d1.x + d2.x, d1.y + d2.y, d1.z + d2.z,};
+	return (Vect){d1.x + d2.x, d1.y + d2.y, d1.z + d2.z};
 }
 
 
-Dot
-subdot(Dot d1, Dot d2)
+Vect
+subvect(Vect d1, Vect d2)
 {
-	return adddot(d1, (Dot){-d2.x, -d2.y, -d2.z});
+	return addvect(d1, (Vect){-d2.x, -d2.y, -d2.z});
 }
 
+Vect
+topolar(Vect v)
+{
+	return (Vect){atan(v.y/v.z)*2/PI,
+		atan(v.x/v.z)*2/PI, vectmod(v)};
+}
+
+double
+vectscalar(Vect d1, Vect d2)
+{
+	return d1.x * d2.x + d1.y * d2.y + d1.z * d2.z;
+}
 int
 spherehit(Ray *v, Sphere s)
 {
@@ -78,10 +81,11 @@ spherehit(Ray *v, Sphere s)
 	int i;
 	old = Inf(1);
 	for (i = 0; i < 1024; i++) {
-		d = dotmod(subdot(v->pos, s.pos)) - s.radius;
-		v->pos = adddot(v->pos,
-			dotxdot(dotnorm(v->dir), (Dot){d, d, d}));
-		if (d < 0.0001) {
+		d = vectmod(subvect(v->pos, s.pos)) - s.radius;
+		v->pos = addvect(v->pos,
+			vectxvect(vectnorm(v->dir), (Vect){d, d, d}));
+		if (d < 0.00001) {
+			v->dir = subvect(s.pos, v->pos);
 			return 1;
 		}
 		if (d > old) return 0;
@@ -90,28 +94,37 @@ spherehit(Ray *v, Sphere s)
 	return 0;
 }
 
-Pixel
+Vect
 ray(Ray v)
 {
-	Pixel p = Pblack;
+	Vect vv;
+	vv = v.pos;
+	Sphere sphere = {{0, 0, 10}, 0.95};
+	Vect light = vectnorm((Vect){10, -10, 10});
+	Vect p = Pblack;
 	if (spherehit(&v, sphere)) {
-		p = Pwhite;
+		double f;
+		Vect r;
+		r = vectnorm(v.dir);
+		f = vectscalar(r, light)/(vectmod(light)*vectmod(r));
+		if (f < 0) f = 0;
+		p = (Vect){f, f, f};
 	}
 	return p;
 }
 
-int
+u32int
 render(int x, int y)
 {
-	Pixel p;
-	int r, g, b;
+	Vect p;
+	u32int r, g, b;
 	Ray v;
-	v.pos = (Dot){ (double)x/256.0, (double)y/256.0, -100 };
-	v.dir = (Dot){ 0, 0, 1 };
+	v.pos = (Vect){ (double)x/128.0 - 1, (double)y/128.0 - 1, -100 };
+	v.dir = (Vect){ 0, 0, 1 };
 	p = ray(v);
-	r = 0xff * p.r;
-	g = 0xff * p.g;
-	b = 0xff * p.b;
+	r = (u32int)(0xff * p.x)&0xff;
+	g = (u32int)(0xff * p.y)&0xff;
+	b = (u32int)(0xff * p.z)&0xff;
 	return (r<<16)|(g<<8)|b;
 }
 
@@ -119,7 +132,7 @@ void
 main(void)
 {
 	int i, x, y;
-	int buf[256*256];
+	u32int buf[256*256];
 	write(1, "   x8r8g8b8 ", 12);
 	write(1, "          0 ", 12);
 	write(1, "          0 ", 12);
@@ -132,4 +145,4 @@ main(void)
 	}
 	write(1, buf, 4 * 256 * 256);
 	exits(nil);
-}
-\ No newline at end of file
+}