diff --git a/src/modules/image/wrap_ImageData.lua b/src/modules/image/wrap_ImageData.lua
index 31a3a06d6..56c4a01e2 100644
--- a/src/modules/image/wrap_ImageData.lua
+++ b/src/modules/image/wrap_ImageData.lua
@@ -23,8 +23,9 @@ misrepresented as being the original software.
 --]]
 
 local ImageData_mt, ffifuncspointer = ...
+local ImageData = ImageData_mt.__index
 
-local tonumber, assert = tonumber, assert
+local tonumber, assert, error = tonumber, assert, error
 local type, pcall = type, pcall
 
 local function inside(x, y, w, h)
@@ -33,7 +34,7 @@ end
 
 -- Implement thread-safe ImageData:mapPixel regardless of whether the FFI is
 -- used or not.
-function ImageData_mt.__index:mapPixel(func, ix, iy, iw, ih)
+function ImageData:mapPixel(func, ix, iy, iw, ih)
 	local idw, idh = self:getDimensions()
 
 	ix = ix or 0
@@ -41,13 +42,13 @@ function ImageData_mt.__index:mapPixel(func, ix, iy, iw, ih)
 	iw = iw or idw
 	ih = ih or idh
 
-	assert(type(ix) == "number", "Invalid argument #2 to ImageData:mapPixel (expected number)")
-	assert(type(iy) == "number", "Invalid argument #3 to ImageData:mapPixel (expected number)")
-	assert(type(iw) == "number", "Invalid argument #4 to ImageData:mapPixel (expected number)")
-	assert(type(ih) == "number", "Invalid argument #5 to ImageData:mapPixel (expected number)")
+	if type(ix) ~= "number" then error("Invalid argument #2 to ImageData:mapPixel (expected number)", 2) end
+	if type(iy) ~= "number" then error("Invalid argument #3 to ImageData:mapPixel (expected number)", 2) end
+	if type(iw) ~= "number" then error("Invalid argument #4 to ImageData:mapPixel (expected number)", 2) end
+	if type(ih) ~= "number" then error("Invalid argument #5 to ImageData:mapPixel (expected number)", 2) end
 
-	assert(type(func) == "function", "Invalid argument #1 to ImageData:mapPixel (expected function)")
-	assert(inside(ix, iy, idw, idh) and inside(ix+iw-1, iy+ih-1, idw, idh), "Invalid rectangle dimensions")
+	if type(func) ~= "function" then error("Invalid argument #1 to ImageData:mapPixel (expected function)", 2) end
+	if not (inside(ix, iy, idw, idh) and inside(ix+iw-1, iy+ih-1, idw, idh)) then error("Invalid rectangle dimensions", 2) end
 
 	-- performAtomic and mapPixelUnsafe have Lua-C API and FFI versions.
 	self:_performAtomic(self._mapPixelUnsafe, self, func, ix, iy, iw, ih)
@@ -85,9 +86,9 @@ local ffifuncs = ffi.cast("FFI_ImageData *", ffifuncspointer)
 
 local pixelpointer = ffi.typeof("ImageData_Pixel *")
 
-local _getWidth = ImageData_mt.__index.getWidth
-local _getHeight = ImageData_mt.__index.getHeight
-local _getDimensions = ImageData_mt.__index.getDimensions
+local _getWidth = ImageData.getWidth
+local _getHeight = ImageData.getHeight
+local _getDimensions = ImageData.getDimensions
 
 -- Table which holds ImageData objects as keys, and information about the objects
 -- as values. Uses weak keys so the ImageData objects can still be GC'd properly.
@@ -111,7 +112,7 @@ local objectcache = setmetatable({}, {
 
 -- Overwrite existing functions with new FFI versions.
 
-function ImageData_mt.__index:_performAtomic(...)
+function ImageData:_performAtomic(...)
 	ffifuncs.lockMutex(self)
 	local success, err = pcall(...)
 	ffifuncs.unlockMutex(self)
@@ -121,7 +122,7 @@ function ImageData_mt.__index:_performAtomic(...)
 	end
 end
 
-function ImageData_mt.__index:_mapPixelUnsafe(func, ix, iy, iw, ih)
+function ImageData:_mapPixelUnsafe(func, ix, iy, iw, ih)
 	local p = objectcache[self]
 	local idw, idh = p.width, p.height
 
@@ -139,9 +140,9 @@ function ImageData_mt.__index:_mapPixelUnsafe(func, ix, iy, iw, ih)
 	end
 end
 
-function ImageData_mt.__index:getPixel(x, y)
+function ImageData:getPixel(x, y)
 	local p = objectcache[self]
-	assert(inside(x, y, p.width, p.height), "Attempt to get out-of-range pixel!")
+	if not inside(x, y, p.width, p.height) then error("Attempt to get out-of-range pixel!", 2) end
 
 	ffifuncs.lockMutex(self)
 	local pixel = p.pointer[y * p.width + x]
@@ -153,9 +154,9 @@ end
 
 local temppixel = ffi.new("ImageData_Pixel")
 
-function ImageData_mt.__index:setPixel(x, y, r, g, b, a)	
+function ImageData:setPixel(x, y, r, g, b, a)	
 	local p = objectcache[self]
-	assert(inside(x, y, p.width, p.height), "Attempt to set out-of-range pixel!")
+	if not inside(x, y, p.width, p.height) then error("Attempt to set out-of-range pixel!", 2) end
 
 	if type(r) == "table" then
 		local t = r
@@ -172,15 +173,15 @@ function ImageData_mt.__index:setPixel(x, y, r, g, b, a)
 	ffifuncs.unlockMutex(self)
 end
 
-function ImageData_mt.__index:getWidth()
+function ImageData:getWidth()
 	return objectcache[self].width
 end
 
-function ImageData_mt.__index:getHeight()
+function ImageData:getHeight()
 	return objectcache[self].height
 end
 
-function ImageData_mt.__index:getDimensions()
+function ImageData:getDimensions()
 	local p = objectcache[self]
 	return p.width, p.height
 end
diff --git a/src/modules/math/wrap_Math.cpp b/src/modules/math/wrap_Math.cpp
index 34381d0fe..ffe1a7590 100644
--- a/src/modules/math/wrap_Math.cpp
+++ b/src/modules/math/wrap_Math.cpp
@@ -318,33 +318,27 @@ int w_linearToGamma(lua_State *L)
 
 int w_noise(lua_State *L)
 {
-	float w, x, y, z;
-	float val;
+	int nargs = std::min(std::max(lua_gettop(L), 1), 4);
+	float args[4];
 
-	switch (lua_gettop(L))
+	for (int i = 0; i < nargs; i++)
+		args[i] = (float) luaL_checknumber(L, i + 1);
+
+	float val = 0.0f;
+
+	switch (nargs)
 	{
 	case 1:
-		x = (float) luaL_checknumber(L, 1);
-		val = Math::instance.noise(x);
+		val = Math::instance.noise(args[0]);
 		break;
 	case 2:
-		x = (float) luaL_checknumber(L, 1);
-		y = (float) luaL_checknumber(L, 2);
-		val = Math::instance.noise(x, y);
+		val = Math::instance.noise(args[0], args[1]);
 		break;
 	case 3:
-		x = (float) luaL_checknumber(L, 1);
-		y = (float) luaL_checknumber(L, 2);
-		z = (float) luaL_checknumber(L, 3);
-		val = Math::instance.noise(x, y, z);
+		val = Math::instance.noise(args[0], args[1], args[2]);
 		break;
 	case 4:
-	default:
-		x = (float) luaL_checknumber(L, 1);
-		y = (float) luaL_checknumber(L, 2);
-		z = (float) luaL_checknumber(L, 3);
-		w = (float) luaL_checknumber(L, 4);
-		val = Math::instance.noise(x, y, z, w);
+		val = Math::instance.noise(args[0], args[1], args[2], args[3]);
 		break;
 	}
 
diff --git a/src/modules/sound/wrap_SoundData.lua b/src/modules/sound/wrap_SoundData.lua
index 5f7991504..c71d60e4e 100644
--- a/src/modules/sound/wrap_SoundData.lua
+++ b/src/modules/sound/wrap_SoundData.lua
@@ -23,6 +23,7 @@ misrepresented as being the original software.
 --]]
 
 local SoundData_mt = ...
+local SoundData = SoundData_mt.__index
 
 if type(jit) ~= "table" or not jit.status() then
 	-- LuaJIT's FFI is *much* slower than LOVE's regular methods when the JIT
@@ -33,18 +34,18 @@ end
 local status, ffi = pcall(require, "ffi")
 if not status then return end
 
-local tonumber, assert = tonumber, assert
+local tonumber, assert, error = tonumber, assert, error
 
 local float = ffi.typeof("float")
 local datatypes = {ffi.typeof("uint8_t *"), ffi.typeof("int16_t *")}
 
 local typemaxvals = {0x7F, 0x7FFF}
 
-local _getBitDepth = SoundData_mt.__index.getBitDepth
-local _getSampleCount = SoundData_mt.__index.getSampleCount
-local _getSampleRate = SoundData_mt.__index.getSampleRate
-local _getChannels = SoundData_mt.__index.getChannels
-local _getDuration = SoundData_mt.__index.getDuration
+local _getBitDepth = SoundData.getBitDepth
+local _getSampleCount = SoundData.getSampleCount
+local _getSampleRate = SoundData.getSampleRate
+local _getChannels = SoundData.getChannels
+local _getDuration = SoundData.getDuration
 
 -- Table which holds SoundData objects as keys, and information about the objects
 -- as values. Uses weak keys so the SoundData objects can still be GC'd properly.
@@ -73,9 +74,13 @@ local objectcache = setmetatable({}, {
 
 -- Overwrite existing functions with new FFI versions.
 
-function SoundData_mt.__index:getSample(i)
+function SoundData:getSample(i)
 	local p = objectcache[self]
-	assert(i >= 0 and i < p.size/p.bytedepth, "Attempt to get out-of-range sample!")
+
+	if not (i >= 0 and i < p.size/p.bytedepth) then
+		error("Attempt to get out-of-range sample!", 2)
+	end
+
 	if p.bytedepth == 2 then
 		-- 16-bit data is stored as signed values internally.
 		return tonumber(p.pointer[i]) / p.maxvalue
@@ -85,9 +90,13 @@ function SoundData_mt.__index:getSample(i)
 	end
 end
 
-function SoundData_mt.__index:setSample(i, sample)
+function SoundData:setSample(i, sample)
 	local p = objectcache[self]
-	assert(i >= 0 and i < p.size/p.bytedepth, "Attempt to set out-of-range sample!")
+
+	if not (i >= 0 and i < p.size/p.bytedepth) then
+		error("Attempt to set out-of-range sample!", 2)
+	end
+
 	if p.bytedepth == 2 then
 		-- 16-bit data is stored as signed values internally.
 		p.pointer[i] = sample * p.maxvalue
@@ -99,23 +108,23 @@ function SoundData_mt.__index:setSample(i, sample)
 	end
 end
 
-function SoundData_mt.__index:getBitDepth()
+function SoundData:getBitDepth()
 	return objectcache[self].bytedepth * 8
 end
 
-function SoundData_mt.__index:getSampleCount()
+function SoundData:getSampleCount()
 	return objectcache[self].samplecount
 end
 
-function SoundData_mt.__index:getSampleRate()
+function SoundData:getSampleRate()
 	return objectcache[self].samplerate
 end
 
-function SoundData_mt.__index:getChannels()
+function SoundData:getChannels()
 	return objectcache[self].channels
 end
 
-function SoundData_mt.__index:getDuration()
+function SoundData:getDuration()
 	return objectcache[self].duration
 end