From 1475ee6e40b61ba2b604ac6dc3ff285df415450f Mon Sep 17 00:00:00 2001
From: ShadowNinja <shadowninja@minetest.net>
Date: Thu, 17 Nov 2016 17:48:19 +0100
Subject: [PATCH] Add trace_node_ray_fat and use it for mining lasers
---
technic/helpers.lua | 79 +++++++++++++++++++++++++++++++++++++++
1 files changed, 79 insertions(+), 0 deletions(-)
diff --git a/technic/helpers.lua b/technic/helpers.lua
index f0c2fc6..5780f27 100644
--- a/technic/helpers.lua
+++ b/technic/helpers.lua
@@ -110,3 +110,82 @@
end, vector.round(pos)
end
+
+--- Like trace_node_ray, but includes extra positions close to the ray.
+function technic.trace_node_ray_fat(pos, dir, range)
+ local x_step = dir.x > 0 and 1 or -1
+ local y_step = dir.y > 0 and 1 or -1
+ local z_step = dir.z > 0 and 1 or -1
+
+ local next_poses = {}
+
+ local i = 1
+ return function(p)
+ local ni, np = next(next_poses)
+ if np then
+ next_poses[ni] = nil
+ return np
+ end
+
+ -- Approximation of where we should be if we weren't rounding
+ -- to nodes. This moves forward a bit faster then we do.
+ -- A correction is done below.
+ local real_x = pos.x + (dir.x * i)
+ local real_y = pos.y + (dir.y * i)
+ local real_z = pos.z + (dir.z * i)
+
+ -- How far off we've gotten from where we should be.
+ local dx = math.abs(real_x - p.x)
+ local dy = math.abs(real_y - p.y)
+ local dz = math.abs(real_z - p.z)
+
+ -- If the real position moves ahead too fast, stop it so we
+ -- can catch up. If it gets too far ahead it will smooth
+ -- out our movement too much and we won't turn fast enough.
+ if dx + dy + dz < 2 then
+ i = i + 1
+ end
+
+ -- Step in whichever direction we're most off course in.
+ local sx, sy, sz -- Whether we've already stepped along each axis
+ if dx > dy then
+ if dx > dz then
+ sx = true
+ p.x = p.x + x_step
+ else
+ sz = true
+ p.z = p.z + z_step
+ end
+ elseif dy > dz then
+ sy = true
+ p.y = p.y + y_step
+ else
+ sz = true
+ p.z = p.z + z_step
+ end
+
+ if vector.distance(pos, p) > range then
+ return nil
+ end
+
+ -- Add other positions that we're significantly off on.
+ -- We can just use fixed integer keys here because the
+ -- table will be completely cleared before we reach this
+ -- code block again.
+ local dlen = math.sqrt(dx*dx + dy*dy + dz*dz)
+ -- Normalized axis deltas
+ local dxn, dyn, dzn = dx / dlen, dy / dlen, dz / dlen
+ if not sx and dxn > 0.5 then
+ next_poses[1] = vector.new(p.x + x_step, p.y, p.z)
+ end
+ if not sy and dyn > 0.5 then
+ next_poses[2] = vector.new(p.x, p.y + y_step, p.z)
+ end
+ if not sz and dzn > 0.5 then
+ next_poses[3] = vector.new(p.x, p.y, p.z + z_step)
+ end
+
+ return p
+ end, vector.round(pos)
+end
+
--
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