Add Simplex shake, with test collection.

rendercam/camera.script

@@ -8,6 +8,7 @@ local rendercam = require "rendercam.rendercam"
 local transform = require "rendercam.transform"
 local debugdraw = require "rendercam.debug-draw"
 local rdebug = rendercam.debug
+local simplex = require "rendercam.simplex2d"
 
 go.property("parent", msg.url())
 go.property("active", true)
@@ -283,14 +284,23 @@ function on_message(self, message_id, message, sender)
 
 		-- Camera Shake.
 		self.shake.x = 0;  self.shake.y = 0;  self.shake.z = 0
-		for i=#data.shakes, 1, -1 do -- iterate backwards so I can remove arbitrary elements without problems
-			local v = data.shakes[i]
-			local d = math.random() * v.dist * v.t / v.dur -- linear falloff
-			local angle = math.random() * TWO_PI
-			self.shake = self.shake + data.lrightVec * math.sin(angle) * d -- Local shake pos.
-			self.shake = self.shake + data.lupVec * math.cos(angle) * d
-			v.t = v.t - self.dt
-			if v.t <= 0 then  table.remove(data.shakes, i)  end
+		for i=#data.shakes,1,-1 do -- Iterate backwards so elements can be removed without problems.
+			local sh = data.shakes[i]
+			local falloffMult = sh.t / sh.dur
+			local x, y
+			if sh.freq then -- Simplex shake.
+				local d = sh.dist * falloffMult
+				x = simplex(sh.seed1, sh.t * sh.freq) * d
+				y = simplex(sh.seed2, sh.t * sh.freq) * d
+			else -- Standard random shake.
+				local d = math.random() * sh.dist * falloffMult
+				local angle = math.random() * TWO_PI
+				x = math.cos(angle) * d;  y = math.sin(angle) * d
+			end
+			self.shake = self.shake + data.lrightVec * x -- Local shake pos.
+			self.shake = self.shake + data.lupVec * y
+			sh.t = sh.t - self.dt
+			if sh.t <= 0 then  table.remove(data.shakes, i)  end
 		end
 		if self.shake.x ~= 0 or self.shake.y ~= 0 or self.shake.z ~= 0 then
 			-- Convert shake from a local offset from the camera to an absolute world position.

rendercam/rendercam.lua

@@ -236,9 +236,15 @@ function M.set_bounds(left, right, top, bottom, cam_id)
 	end
 end
 
-function M.shake(dist, dur, cam_id)
+function M.shake(dist, dur, freq, cam_id)
 	local cam = validate_cam_id(cam_id, "shake")
-	table.insert(cam.shakes, { dist = dist, dur = dur, t = dur })
+	local t = { dist = dist, dur = dur, t = dur }
+	if freq then -- Simplex shake.
+		t.freq = freq
+		t.seed1 = math.random() * 1000
+		t.seed2 = t.seed1 + 1
+	end
+	table.insert(cam.shakes, t)
 end
 
 function M.recoil(vec, dur, cam_id)

rendercam/simplex2d.lua

@@ -0,0 +1,125 @@
+
+--[[
+The MIT License (MIT)
+
+Copyright (c) 2019 Christopher E. Moore ( [email protected] / http://christopheremoore.net )
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+--]]
+
+-- local bit = bit32 or require 'bit'
+
+-- 2D simplex noise
+
+local grad3 = {
+	{1,1,0},{-1,1,0},{1,-1,0},{-1,-1,0},
+	{1,0,1},{-1,0,1},{1,0,-1},{-1,0,-1},
+	{0,1,1},{0,-1,1},{0,1,-1},{0,-1,-1}
+}
+
+local p = {151,160,137,91,90,15,
+	131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
+	190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
+	88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
+	77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
+	102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
+	135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
+	5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
+	223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
+	129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
+	251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
+	49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
+	138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180}
+local perm = {}
+for i=0,511 do
+	perm[i+1] = p[bit.band(i, 255) + 1]
+end
+
+local function dot(g, ...)
+	local v = {...}
+	local sum = 0
+	for i=1,#v do
+		sum = sum + v[i] * g[i]
+	end
+	return sum
+end
+
+local function noise(xin, yin)
+	local n0, n1, n2	-- Noise contributions from the three corners
+	-- Skew the input space to determine which simplex cell we're in
+	local F2 = 0.5*(math.sqrt(3.0)-1.0)
+	local s = (xin+yin)*F2; -- Hairy factor for 2D
+	local i = math.floor(xin+s)
+	local j = math.floor(yin+s)
+	local G2 = (3.0-math.sqrt(3.0))/6.0
+	local t = (i+j)*G2
+	local X0 = i-t -- Unskew the cell origin back to (x,y) space
+	local Y0 = j-t
+	local x0 = xin-X0 -- The x,y distances from the cell origin
+	local y0 = yin-Y0
+	-- For the 2D case, the simplex shape is an equilateral triangle.
+	-- Determine which simplex we are in.
+	local i1, j1 -- Offsets for second (middle) corner of simplex in (i,j) coords
+	if x0 > y0 then
+		i1 = 1
+		j1 = 0 -- lower triangle, XY order: (0,0)->(1,0)->(1,1)
+	else
+		i1 = 0
+		j1 = 1
+	end-- upper triangle, YX order: (0,0)->(0,1)->(1,1)
+	-- A step of (1,0) in (i,j) means a step of (1-c,-c) in (x,y), and
+	-- a step of (0,1) in (i,j) means a step of (-c,1-c) in (x,y), where
+	-- c = (3-sqrt(3))/6
+	local x1 = x0 - i1 + G2 -- Offsets for middle corner in (x,y) unskewed coords
+	local y1 = y0 - j1 + G2
+	local x2 = x0 - 1 + 2 * G2 -- Offsets for last corner in (x,y) unskewed coords
+	local y2 = y0 - 1 + 2 * G2
+	-- Work out the hashed gradient indices of the three simplex corners
+	local ii = bit.band(i, 255)
+	local jj = bit.band(j, 255)
+	local gi0 = perm[ii + perm[jj+1]+1] % 12
+	local gi1 = perm[ii + i1 + perm[jj + j1+1]+1] % 12
+	local gi2 = perm[ii + 1 + perm[jj + 1+1]+1] % 12
+	-- Calculate the contribution from the three corners
+	local t0 = 0.5 - x0 * x0 - y0 * y0
+	if t0 < 0 then
+		n0 = 0.0
+	else
+		t0 = t0 * t0
+		n0 = t0 * t0 * dot(grad3[gi0+1], x0, y0) -- (x,y) of grad3 used for 2D gradient
+	end
+	local t1 = 0.5 - x1 * x1 - y1 * y1
+	if t1 < 0 then
+		n1 = 0.0
+	else
+		t1 = t1 * t1
+		n1 = t1 * t1 * dot(grad3[gi1+1], x1, y1)
+	end
+	local t2 = 0.5 - x2 * x2 - y2 * y2
+	if t2 < 0 then
+		n2 = 0.0
+	else
+		t2 = t2 * t2
+		n2 = t2 * t2 * dot(grad3[gi2+1], x2, y2)
+	end
+	-- Add contributions from each corner to get the final noise value.
+	-- The result is scaled to return values in the interval [-1,1].
+	return 70.0 * (n0 + n1 + n2)
+end
+
+return noise

tests/visual/basic test controls.script

@@ -100,7 +100,7 @@ function on_input(self, action_id, action)
 		rendercam.zoom_in(mouseWheelZoomIncrement)
 	elseif action_id == hash("space") and action.pressed then
 		local sh = shakes[self.shakeIndex]
-		rendercam.shake(sh.dist, sh.dur)
+		rendercam.shake(sh.dist, sh.dur, sh.freq)
 		self.shakeIndex = self.shakeIndex % #shakes + 1
 	elseif action_id == hash("enter") and action.pressed then
 		local rec = recoils[self.recoilIndex]