Calculate a better bounding box for the rings by calculating their radius.

2 files changed, 18 insertions, 1 deletions

diff --git a/glass.c b/glass.c
index a0711a7..486b257 100644
--- a/glass.c
+++ b/glass.c
@@ -265,7 +265,7 @@ calc_new_ring_transforms(int instance)
 	 * So we're just making a bounding box and doing a bounding sphere
 	 * of it, really.
 	 */
-	ring_bounding_sphere_radius = sqrt((7.5 * 7.5) * 3);
+	ring_bounding_sphere_radius = sqrt((5 + ring.radius) * (5 + ring.radius) * 3);
 }
 
 static void
@@ -396,13 +396,19 @@ revolve(const float *verts, unsigned int num_verts,
 	float unrotated_tangent4[4];
 	float texcoord_len = 0;
 
+	/* calculate the radius of the ring. */
+	for (i = 0; i < num_verts; i++) {
+	}
+
 	/* Calculate the 4-component vertex and normalized normal data
 	 * that will be rotated around.
 	 */
+	ring.radius = 0;
 	for (i = 0; i < num_verts; i++) {
 		int v0; /* previous vertex */
 		int v2; /* next vertex */
 		float v0_v2[2], v1_v2[2], normal_len;
+		float position[4], this_radius;
 
 		/* Expand vertex data out to 4f, so we can use the same
 		 * matrix functions.
@@ -412,6 +418,15 @@ revolve(const float *verts, unsigned int num_verts,
 		verts4[i * 4 + 2] = 0.0;
 		verts4[i * 4 + 3] = 1.0;
 
+		mult_m4_p4(position,
+			   translation_matrix,
+			   &verts4[i * 4]);
+		this_radius = sqrt(position[0] * position[0] +
+				   position[1] * position[1] +
+				   position[2] * position[2]);
+		if (this_radius > ring.radius)
+			ring.radius = this_radius;
+
 		if (i == 0)
 			v0 = num_verts - 1;
 		else
diff --git a/glass.h b/glass.h
index ac857c2..d3950ff 100644
--- a/glass.h
+++ b/glass.h
@@ -34,6 +34,8 @@ struct revolved_object {
 	int pos_offset, norm_offset, tangent_offset, texcoord_offset;
 	int elements_offset, elements_vert_stride;
 	int num_verts, num_steps;
+	/* Maximum distance from center of revolution to a vertex. */
+	float radius;
 };
 
 enum ground_uniform_list {