66 lines
2.7 KiB
Markdown
66 lines
2.7 KiB
Markdown
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### Fiel of view for monsters vs characters
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From https://forum.minetest.net/viewtopic.php?p=182737#p182737
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If it helps any, here is the in_fov code from mobs redo mod that works (self is mob, pos is player position and self.fov is set to 90, self.rotate is usually 0 for front facing mobs):
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CODE: SELECT ALL
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```
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in_fov = function(self,pos)
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-- checks if POS is in self's FOV
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local yaw = self.object:getyaw() + self.rotate
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local vx = math.sin(yaw)
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local vz = math.cos(yaw)
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local ds = math.sqrt(vx^2 + vz^2)
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local ps = math.sqrt(pos.x^2 + pos.z^2)
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local d = { x = vx / ds, z = vz / ds }
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local p = { x = pos.x / ps, z = pos.z / ps }
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local an = ( d.x * p.x ) + ( d.z * p.z )
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a = math.deg( math.acos( an ) )
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```
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Thank you everyone, especially TeTpaAka and Nore. All problems were at last solved, and the code now reports the angle difference between entities like it should! You get 0* when standing right in front of the mob, 90* when standing parallel to either side, 180* when standing behind... whereas flying up or down now accounts pitch correctly on top of that.
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Here is the final and fully functional version. I hope it will be helpful to more people than just me, if anyone ever needs a simple and efficient FOV scanner for Minetest.
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```
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local function in_fov (pos1, pos2, yaw, pitch, fov)
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local function yaw2vec (yaw, pitch)
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-- we must invert the yaw for x to keep the result from inverting when facing opposite directions (0* becoming 180*)
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return {x = math.sin(-yaw) * math.cos(pitch), y = math.sin(pitch), z = math.cos(yaw) * math.cos(pitch)}
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end
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local function dotproduct (v1, v2)
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return ((v1.x * v2.x) + (v1.y * v2.y) + (v1.z * v2.z))
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end
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local function angle (v1, v2)
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return math.deg(math.acos(dotproduct(v1, v2) / (vector.length(v1) * vector.length(v2))))
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end
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local v = vector.subtract(pos2, pos1)
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print(angle(yaw2vec(yaw, pitch), v))
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end
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```
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here is the final version of the function which I'll be including in my mod, simplified to only 5 lines of code but with the same result:
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CODE: SELECT ALL
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```
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-- returns the angle difference between pos1 and pos2, as seen from pos1 at the specified yaw and pitch
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function pos_to_angle (pos1, pos2, yaw, pitch)
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-- note: we must invert the yaw for x in yaw_vec, to keep the result from inverting when facing opposite directions (0* becoming 180*)
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local yaw_vec = {x = -math.sin(yaw) * math.cos(pitch), y = math.sin(pitch), z = math.cos(yaw) * math.cos(pitch)}
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local pos_subtract = vector.subtract(pos2, pos1)
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local pos_dotproduct = (yaw_vec.x * pos_subtract.x) + (yaw_vec.y * pos_subtract.y) + (yaw_vec.z * pos_subtract.z)
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local angle = math.deg(math.acos(pos_dotproduct / (vector.length(yaw_vec) * vector.length(pos_subtract))))
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return angle
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end
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```
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