Ensure the arrays are allocated before checking the camera position i…

…s loadable (early return causes unallocated memory access)

Added defines to select which "shading style" to use
Only allocate the depth array when needed

tiny_bvh_fenster.cpp

@@ -3,6 +3,9 @@
 #define SCRHEIGHT 600
 #include "external/fenster.h" // https://github.com/zserge/fenster
 
+//#define COLOR_PRIM // compute color as hashed triangle Index
+//#define COLOR_DEPTH // compute color as depth of intersection 
+
 #define LOADSCENE
 
 #define TINYBVH_IMPLEMENTATION
@@ -14,7 +17,11 @@ using namespace tinybvh;
 BVH bvh;
 int frameIdx = 0;
 Ray* rays = 0;
+#ifdef COLOR_DEPTH
 int* depths = 0;
+#endif
+
+
 
 #ifdef LOADSCENE
 bvhvec4* vertices = 0;
@@ -106,17 +113,19 @@ void Init()
 	else
 		bvh.BuildHQ( vertices, verts / 3 );
 
+	// allocate buffers
+	rays = (Ray*)tinybvh::malloc64(SCRWIDTH * SCRHEIGHT * 16 * sizeof(Ray));
+#ifdef COLOR_DEPTH
+	depths = (int*)tinybvh::malloc64(SCRWIDTH * SCRHEIGHT * sizeof(int));
+#endif
+
 	// load camera position / direction from file
 	std::fstream t = std::fstream{ "camera.bin", t.binary | t.in };
 	if (!t.is_open()) return;
 	t.seekp( 0 );
 	t.read( (char*)&eye, sizeof( eye ) );
 	t.read( (char*)&view, sizeof( view ) );
 	t.close();
-
-	// allocate buffers
-	rays = (Ray*)tinybvh::malloc64( SCRWIDTH * SCRHEIGHT * 16 * sizeof( Ray ) );
-	depths = (int*)tinybvh::malloc64( SCRWIDTH * SCRHEIGHT * sizeof( int ) );
 }
 
 bool UpdateCamera( float delta_time_s, fenster& f )
@@ -170,27 +179,43 @@ void Tick( float delta_time_s, fenster& f, uint32_t* buf )
 	}
 
 	// trace primary rays
-	for (int i = 0; i < N; i++) depths[i] = bvh.Intersect( rays[i] );
-
+	for (int i = 0; i < N; i++) {
+#ifdef COLOR_DEPTH
+		depths[i] = bvh.Intersect(rays[i]);
+#else 
+		bvh.Intersect(rays[i]);
+#endif
+	}
 	// visualize result
 	const bvhvec3 L = tinybvh_normalize( bvhvec3( 1, 2, 3 ) );
 	for (int i = 0, ty = 0; ty < SCRHEIGHT / 4; ty++) for (int tx = 0; tx < SCRWIDTH / 4; tx++)
 	{
 		for (int y = 0; y < 4; y++) for (int x = 0; x < 4; x++, i++) if (rays[i].hit.t < 10000)
 		{
 			int pixel_x = tx * 4 + x, pixel_y = ty * 4 + y, primIdx = rays[i].hit.prim;
+
+
+#ifdef COLOR_DEPTH
+			buf[pixel_x + pixel_y * SCRWIDTH] = depths[i] << 17; // render depth as red
+#elif defined COLOR_PRIM
+			buf[pixel_x + pixel_y * SCRWIDTH] = (primIdx * 0xdeece66d + 0xb) & 0xFFFFFF; // color is hashed primitive index
+#else
 			int v0idx = primIdx * 3, v1idx = v0idx + 1, v2idx = v0idx + 2;
 			if (inds) v0idx = indices[v0idx], v1idx = indices[v1idx], v2idx = indices[v2idx];
 			bvhvec3 v0 = vertices[v0idx];
 			bvhvec3 v1 = vertices[v1idx];
 			bvhvec3 v2 = vertices[v2idx];
-			bvhvec3 N = tinybvh_normalize( tinybvh_cross( v1 - v0, v2 - v0 ) );
-			int c = (int)(255.9f * fabs( tinybvh_dot( N, L ) ));
+			bvhvec3 N = tinybvh_normalize(tinybvh_cross(v1 - v0, v2 - v0));
+			int c = (int)(255.9f * fabs(tinybvh_dot(N, L)));
 			buf[pixel_x + pixel_y * SCRWIDTH] = c + (c << 8) + (c << 16);
-			// buf[pixel_x + pixel_y * SCRWIDTH] = (primIdx * 0xdeece66d + 0xb) & 0xFFFFFF; // color is hashed primitive index
-			// buf[pixel_x + pixel_y * SCRWIDTH] = depths[i] << 17; // render depth as red
+#endif
 		}
 	}
+
+	// print frame time / rate in window title
+	char title[50];
+	sprintf(title, "tiny_bvh %.2f s %.2f Hz", delta_time_s, 1.0f / delta_time_s);
+	fenster_update_title(&f, title);
 }
 
 void Shutdown()
@@ -204,5 +229,7 @@ void Shutdown()
 
 	// delete allocated buffers
 	tinybvh::free64( rays );
+#ifdef COLOR_DEPTH
 	tinybvh::free64( depths );
+#endif
 }