89 lines
2.4 KiB
Lua
89 lines
2.4 KiB
Lua
--[[
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Some random utilities that can be useful
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]]
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-- Calculate XY position from given degrees (not rad!) and distance
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-- Returns tuple {X, Y} coordinates
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-- Note that either may be negative
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function deg_dist_to_xy(degrees, distance)
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local rad = deg_to_rad(degrees)
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return rad_dist_to_xy(rad, distance)
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end
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function rad_dist_to_xy(radians, distance)
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return {distance * math.cos(radians), distance * math.sin(radians)}
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end
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-- Convert degrees to radians
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function deg_to_rad(degrees)
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return degrees * math.pi / 180
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end
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function rad_to_deg(radians)
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return radians * 180 / math.pi
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end
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-- Convert X,Y to rad from horizontal axle (pointing right)
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function xy_to_rad(x, y)
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-- Avoid division by 0
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if x == 0 then
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if y >= 0 then
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return math.pi / 2
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else
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return math.pi * 1.5
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end
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else
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local angle = math.atan(math.abs(y) / math.abs(x))
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-- Take into account the quadrant we are in
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if x >= 0 and y < 0 then
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return 2 * math.pi - angle
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elseif x < 0 and y < 0 then
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return math.pi + angle
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elseif x < 0 and y >= 0 then
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return math.pi - angle
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else
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return angle
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end
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end
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end
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function xy_to_deg(x, y)
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return rad_to_deg(xy_to_rad(x, y))
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end
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-- Get distance between two points
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function distance(x1, y1, x2, y2)
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return math.sqrt(math.pow(x1 - x2, 2) + math.pow(y1 - y2, 2))
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end
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-- Get objects within a radius from given coordinates in given level
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function getObjectsInRadius(x, y, radius, level, include_player)
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include_player = include_player or false
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local objs = level.world:getBodyList()
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local ret = {}
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for _, body in pairs(objs) do
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if distance(x, y, body:getX(), body:getY()) <= radius then
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if body:getFixtureList()[1]:getUserData() ~= player
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or include_player then
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table.insert(ret, body)
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end
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end
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end
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return ret
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end
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-- Pick a color from a color slide, from rgb0 (0%) to rgb100 (100%)
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function colorSlide(rgb0, rgb100, ratio)
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local red = colorNAKKIVENE(rgb0[1], rgb100[1], ratio)
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local green = colorNAKKIVENE(rgb0[2], rgb100[2], ratio)
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local blue = colorNAKKIVENE(rgb0[3], rgb100[3], ratio)
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return {red, green, blue}
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end
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function colorNAKKIVENE(color100, color0, ratio)
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return ratio * color100 + (1 - ratio) * color0
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end
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