Optimize a little bit isBlockInSight, adjustDist & collisions (#7193)

* Use constexpr + unroll some calculations to cache definitively some calculations
* Unroll some calls in collision code & use a constref instead of a copy in one occurence

1 files changed, 8 insertions, 7 deletions

diff --git a/src/util/numeric.cpp b/src/util/numeric.cpp
index b88b4d545..f533c275f 100644
--- a/src/util/numeric.cpp
+++ b/src/util/numeric.cpp
@@ -108,7 +108,7 @@ bool isBlockInSight(v3s16 blockpos_b, v3f camera_pos, v3f camera_dir,
 {
 	// Maximum radius of a block.  The magic number is
 	// sqrt(3.0) / 2.0 in literal form.
-	const f32 block_max_radius = 0.866025403784 * MAP_BLOCKSIZE * BS;
+	static constexpr const f32 block_max_radius = 0.866025403784f * MAP_BLOCKSIZE * BS;
 
 	v3s16 blockpos_nodes = blockpos_b * MAP_BLOCKSIZE;
 
@@ -125,16 +125,16 @@ bool isBlockInSight(v3s16 blockpos_b, v3f camera_pos, v3f camera_dir,
 	// Total distance
 	f32 d = MYMAX(0, blockpos_relative.getLength() - block_max_radius);
 
-	if(distance_ptr)
+	if (distance_ptr)
 		*distance_ptr = d;
 
 	// If block is far away, it's not in sight
-	if(d > range)
+	if (d > range)
 		return false;
 
 	// If block is (nearly) touching the camera, don't
 	// bother validating further (that is, render it anyway)
-	if(d == 0)
+	if (d == 0)
 		return true;
 
 	// Adjust camera position, for purposes of computing the angle,
@@ -166,12 +166,13 @@ bool isBlockInSight(v3s16 blockpos_b, v3f camera_pos, v3f camera_dir,
 s16 adjustDist(s16 dist, float zoom_fov)
 {
 	// 1.775 ~= 72 * PI / 180 * 1.4, the default on the client
-	const float default_fov = 1.775f;
+	static constexpr const float default_fov = 1.775f / 2.0f;
 	// heuristic cut-off for zooming
-	if (zoom_fov > default_fov / 2.0f)
+	if (zoom_fov > default_fov)
 		return dist;
 
 	// new_dist = dist * ((1 - cos(FOV / 2)) / (1-cos(zoomFOV /2))) ^ (1/3)
-	return round(dist * std::cbrt((1.0f - std::cos(default_fov / 2.0f)) /
+	// note: FOV is calculated at compilation time
+	return round(dist * std::cbrt((1.0f - std::cos(default_fov)) /
 		(1.0f - std::cos(zoom_fov / 2.0f))));
 }