RSW: Add a workaround for NaN light positions

It's not pretty, but it does prevent crashes when loading gl_step...

Core/FileFormats/RagnarokRSW.lua

@@ -266,7 +266,7 @@ function RagnarokRSW:DecodeSceneObjects()
 		if objectTypeID == RagnarokRSW.SCENE_OBJECT_TYPE_ANIMATED_PROP then
 			self:DecodeAnimatedProps()
 		elseif objectTypeID == RagnarokRSW.SCENE_OBJECT_TYPE_DYNAMIC_LIGHT_SOURCE then
-			self:DecodeDynamicLightSources()
+			self:DecodeDynamicLightSource()
 		elseif objectTypeID == RagnarokRSW.SCENE_OBJECT_TYPE_SPATIAL_AUDIO_SOURCE then
 			self:DecodeSpatialAudioSource()
 		elseif objectTypeID == RagnarokRSW.SCENE_OBJECT_TYPE_PARTICLE_EFFECT_EMITTER then
@@ -344,9 +344,14 @@ function RagnarokRSW:DecodeAnimatedProps()
 	tinsert(self.animatedProps, objectInfo)
 end
 
-function RagnarokRSW:DecodeDynamicLightSources()
+function RagnarokRSW:DecodeDynamicLightSource()
 	local objectInfo = self.reader:GetTypedArray("rsw_dynamic_light_t")
 
+	-- Garbage data exists in gl_step: See https://github.com/RagnarokResearchLab/RagLite/issues/343
+	if not objectInfo.position.y then
+		objectInfo.position.y = -1 * 5 * 29.8 -- Denormalized Y of nearby light sources (workaround)
+	end
+
 	local lightSource = {
 		name = ffi_string(objectInfo.name),
 		normalizedWorldPosition = {

Tests/FileFormats/RagnarokRSW.spec.lua

@@ -1,3 +1,4 @@
+local BinaryReader = require("Core.FileFormats.BinaryReader")
 local QuadTreeRange = require("Core.FileFormats.RSW.QuadTreeRange")
 local RagnarokRSW = require("Core.FileFormats.RagnarokRSW")
 
@@ -904,4 +905,19 @@ describe("RagnarokRSW", function()
 			assertEquals(rsw.sceneGraph:GetBinaryStorageSize(), 65520) -- This will have to do (for now)
 		end)
 	end)
+
+	describe("DecodeDynamicLightSource", function()
+		it("should be able to handle NaN values without crashing", function()
+			local name = string.rep("\000", 80)
+			local position = string.rep("\000", 4) .. string.rep("\255", 4) .. string.rep("\000", 4)
+			local color = string.rep("\000", 12)
+			local intensity = string.rep("\000", 4)
+			local garbageBytes = name .. position .. color .. intensity
+
+			local rsw = RagnarokRSW()
+			rsw.reader = BinaryReader(garbageBytes)
+			rsw:DecodeDynamicLightSource()
+			assertEquals(rsw.dynamicLightSources[1].normalizedWorldPosition.y, 29.8)
+		end)
+	end)
 end)