octree

commit ba7443a2cdd8fe83d60ce3236d3d2d4470210139
parent 563ba2d1774f8d785977e68883919605b2f610eb
Author: Pavel Renev <an2qzavok@gmail.com>
Date:   Sun, 28 Mar 2021 16:08:05 +0000

implement perspective projection

Diffstat:
M
render.c
 | 
36
+++++++++++++++++++++++-------------

1 file changed, 23 insertions(+), 13 deletions(-)
diff --git a/render.c b/render.c
@@ -3,6 +3,7 @@
 
 #include "octree.h"
 
+#define BSIZE 512
 #define SQR(X) (X * X)
 
 typedef struct Vect Vect;
@@ -62,11 +63,15 @@ subvect(Vect d1, Vect d2)
 	return addvect(d1, (Vect){-d2.x, -d2.y, -d2.z});
 }
 
+
 Vect
-topolar(Vect v)
+todecart(Vect v)
 {
-	return (Vect){atan(v.y/v.z)*2/PI,
-		atan(v.x/v.z)*2/PI, vectmod(v)};
+	return (Vect) {
+		v.z * sin(v.x),
+		v.z * sin(v.y),
+		hypot(v.z * cos(v.y), v.z * cos(v.x)),
+	};
 }
 
 double
@@ -84,7 +89,7 @@ spherehit(Ray *v, Sphere s)
 		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) {
+		if (d < 0.001) {
 			v->dir = subvect(s.pos, v->pos);
 			return 1;
 		}
@@ -116,11 +121,16 @@ ray(Ray v)
 u32int
 render(int x, int y)
 {
+	double fov;
 	Vect p;
 	u32int r, g, b;
 	Ray v;
-	v.pos = (Vect){ (double)x/128.0 - 1, (double)y/128.0 - 1, -100 };
-	v.dir = (Vect){ 0, 0, 1 };
+	fov = PI/2;
+	v.pos = (Vect) { 0, 0, -1 };
+	v.dir = todecart((Vect) {
+		fov*((double)x/BSIZE - 0.5),
+		fov*((double)y/BSIZE - 0.5),
+		1});
 	p = ray(v);
 	r = (u32int)(0xff * p.x)&0xff;
 	g = (u32int)(0xff * p.y)&0xff;
@@ -132,17 +142,17 @@ void
 main(void)
 {
 	int i, x, y;
-	u32int buf[256*256];
+	u32int buf[SQR(BSIZE)];
 	write(1, "   x8r8g8b8 ", 12);
 	write(1, "          0 ", 12);
 	write(1, "          0 ", 12);
-	write(1, "        256 ", 12);
-	write(1, "        256 ", 12);
-	for (i = 0; i < 256 * 256; i++) {
-		x = i%256;
-		y = 255-(i/256);
+	fprint(1, "%11d ", BSIZE);
+	fprint(1, "%11d ", BSIZE);
+	for (i = 0; i < SQR(BSIZE); i++) {
+		x = i%BSIZE;
+		y = BSIZE-(i/BSIZE);
 		buf[i] = render(x, y);
 	}
-	write(1, buf, 4 * 256 * 256);
+	write(1, buf, 4 * SQR(BSIZE));
 	exits(nil);
 }