stew

commit f64e0f22830ca6712d361e889d61275bf417ba95
parent fea1ed5534469940e59fceb50af2af0c18dc9bdd
Author: Renev Pavel <an2qzavok@gmail.com>
Date:   Fri, 18 Nov 2022 00:39:30 +0000

cubes: some tinkerin'

Diffstat:
M
src/cubes/cubes.c
 | 
74
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-------

1 file changed, 67 insertions(+), 7 deletions(-)
diff --git a/src/cubes/cubes.c b/src/cubes/cubes.c
@@ -66,6 +66,28 @@ raynorm(Raydef r)
  */
 
 Raydef
+intersectX(Raydef ray, double X)
+{
+	Raydef ref;
+	double t;
+	if (ray.D[0] >= X) {
+		Raydef ret = {
+		  {Inf(ray.D[0]), Inf(ray.D[1]), Inf(ray.D[2])},
+		  {ray.D[0], ray.D[1], ray.D[2]},
+		};
+		return ret;
+	}
+	t = (X-ray.O[0]) / ray.D[0];
+	ref.O[0] = X;
+	ref.O[1] = ray.O[1] + ray.D[1] * t;
+	ref.O[2] = ray.O[2] + ray.D[2] * t;
+	ref.D[0] = -ray.D[0];
+	ref.D[1] = ray.D[1];
+	ref.D[2] = ray.D[2];
+	return ref;
+}
+
+Raydef
 intersectY(Raydef ray, double Y)
 {
 	Raydef ref;
@@ -87,10 +109,32 @@ intersectY(Raydef ray, double Y)
 	return ref;
 }
 
+Raydef
+intersectZ(Raydef ray, double Z)
+{
+	Raydef ref;
+	double t;
+	if (ray.D[2] >= Z) {
+		Raydef ret = {
+		  {Inf(ray.D[0]), Inf(ray.D[1]), Inf(ray.D[2])},
+		  {ray.D[0], ray.D[1], ray.D[2]},
+		};
+		return ret;
+	}
+	t = (Z-ray.O[0]) / ray.D[0];
+	ref.O[0] = ray.O[0] + ray.D[0] * t;
+	ref.O[1] = ray.O[1] + ray.D[1] * t;
+	ref.O[2] = Z;
+	ref.D[0] = ray.D[0];
+	ref.D[1] = ray.D[1];
+	ref.D[2] = -ray.D[2];
+	return ref;
+}
+
 void
 vrender(void)
 {
-	int i, x, y;
+	int i, j, x, y;
 	double X, Y;
 	for (i = 0, y = 0; y < CSHeight; y++) {
 		Y = (double)(y) / CSHeight;
@@ -98,14 +142,30 @@ vrender(void)
 			X = (double)(x) / CSWidth;
 			// TODO: generate camera ray properly
 			Raydef r = {
-				.O {0, 0, 0},
+				.O {10, 10, 10},
 				.D {-1 + X * 2, 1 - Y * 2, 2}
 			};
-			r = intersectY(r, 0);
-			
-			if (isInf(r.O[0], 0) != 0) imgbuf[i] = 0x004f7fff;
+			Raydef  ref[6];
+			ref[0] = intersectX(r, 0);
+			ref[1] = intersectY(r, 0);
+			ref[2] = intersectZ(r, 0);
+
+			ref[3] = intersectX(r, 0);
+			ref[4] = intersectY(r, 0);
+			ref[5] = intersectZ(r, 0);
+
+			Raydef one; // = infray
+			for (j = 0; j < 6; j++) {
+				// check boundary;
+				if ((ref[j].O[0] < 0) || (ref[j].O[1] < 0) || (ref[j].O[2] < 0))
+					continue;
+				// todo check distance;
+				one = ref[j];
+			}
+			if (isInf(ref[0].O[0], 0) != 0) imgbuf[i] = 0x004f7fff;
 			else {
-				double d = sqrt((r.D[1] * r.D[1]) / (r.D[0] * r.D[0] + r.D[2] * r.D[2]));
+				double d = sqrt((ref[0].D[1] * ref[0].D[1])
+				  / (ref[0].D[0] * ref[0].D[0] + ref[0].D[2] * ref[0].D[2]));
 				int br = 0xff * d;
 				imgbuf[i] = (br << 16) + (br << 8) + (br);
 			}
@@ -126,7 +186,7 @@ void
 eresized(int new)
 {
 	if(new && getwindow(display, Refnone) < 0)
-		fprint(2,"can't reattach to window");
+		sysfatal("can't reattach to window");
 	redraw(screen);
 }