Grim Dawn - PFX File Format Information

Overview
The Grim Dawn .PFX file-format is the binary file-format that the game uses for storing its particle effects.

File Header
PFX files have a single header at the start of the file <65 00 00 00>, which is then followed by a list of its emitters one after each other.

Emitters
Overview
Each emitter section has 5 parts:

• A string containing the emitter-name (see the data-types section regarding the string format)
• A static emitter-type: 'PFX1' <50 46 58 31>
• A terminator?: <00 00 00 00> (Always seems to be empty)
• The length of the rest of the data in this emitter (e.g. 909 <8D 03 00 00>)
• The 5 different sections for each data-type (strings, booleans, ints, floats, and graph-lines)
  

There are no terminators to delineate between each data-type section, it seems to rely on each section-header to determine how many values the following section has, and when you've read that many values you will have reached the next section.

Data Sections
Each of the 5 data-type sections start with a header containing an integer that indicates how many values are within that section (which always seem to be the same):

• Strings :=  3 <30 00 00 00>
• Booleans/Flags := 14 <0E 00 00 00>
• Integers :=  2 <02 00 00 00>
• Floats :=  4 <04 00 00 00>
• Graph-Lines := 26 <1A 00 00 00>
  

Then after that section-header, it lists each value one after each other until it reaches the next data-type section, or the end of the emitter (after the final graph-lines section).

Variable Mapping
Strings/Filepaths (x3)

• Particle Texture (e.g. 'Effects/Default/particletest.tex')
• Shader (e.g. 'Shaders/Particle/ParticleAdditive.ssh')
• Drop Decal (e.g. 'FX/decals/defaultdecal.tex')
  

Booleans/Flags (x14)

• Looping
• Emit Locally
• Motion Orient
• Implode
• Random Orientation
• Flatten Motion
• Light Enabled
• Light Shadows
• Light Off-During-Day
• unknown_9 ??? (Always seems to be False <00 00 00 00>)
• Orient Vertically
• Light Simple
• unknown_12 ??? (Always seems to be False <00 00 00 00>)
• Light Important
  

Integers (x2)

• Emitter Shape (ENUM: [0]Sphere, [1]Plane, [2]Circle, [3]Line, [4]Shell, [5]Skeleton)
• Emitter FPS
  

Floats (x4)

• Particle Lifetime
• Initial Rotation X
• Initial Rotation Y
• Initial Rotation Z
  

Graph-Lines (x26)

• Particle Color - Alpha
• Particle Color - Red
• Particle Color - Green
• Particle Color - Blue
• Particle Rotation
• Particle Size
• Emit Rate
• Emit Velocity
• Particle Gravity
• Emitter Offset X
• Emitter Offset Y
• Emitter Offset Z
• unknown_12 ???
• unknown_13 ???
• Emit Angle
• Emitter Size
• Particle Twirl
• Particle Stretch
• Emitter Rotation X
• Emitter Rotation Y
• Emitter Rotation Z
• Particle Friction
• Light Color - Red
• Light Color - Green
• Light Color - Blue
• Light Radius
  

Data Types
Strings
Editable strings start with a header containing an integer with the length of the string:
e.g. 'New Emitter' := 11 <0B 00 00 00> New Emitter <4E 65 77 20 45 6D 69 74 74 65 72>

If the string is empty, there's just a header with a length of 0:
e.g. "" := 0 <00 00 00 00>

The exception to this seems to be the static emitter-type that is immediately after the emitter-name, which has no length header:
e.g. PFX1 <50 46 58 31>

Booleans/Flags
Booleans are just integers with values of either 1 or 0.
e.g. True <01 00 00 00>, or False <00 00 00 00>

Integers
Integers are little-endian integers of a 4-byte length:
e.g. 0 <00 00 00 00>, 15 <0F 00 00 00>, 30 <1E 00 00 00>

Floats
Floats are big-endian single-precision floating-points of a 4-byte length:
e.g. 1.0 <00 00 80 3F>, 0.5 <00 00 00 3F>, 5.5 <00 00 B0 40>, 10.0 <00 00 20 41>

Graph-Lines
Each graph-line consist of 4 different parts:

• A float containing the X-Scale (time) 
  e.g. 10.0 <00 00 20 41>
  
• A float containing the Y-Scale (value) 
  e.g. 1.0 <00 00 80 3F>
  
• An integer containing the number of points in the proceeding list 
  e.g. 2 <02 00 00 00>
  
• A list of graph-points 
  e.g. <00 00 00 00 00 00 80 3F> <00 00 20 41 00 00 80 3F>
  

Each graph-point consist of 2 floats representing the [x,y] coordinates:
e.g. a static line with 2 points (that stays at 1.0 for 10 seconds): [ [0.0, 1.0], [10.0, 1.0] ]
0.0 <00 00 00 00> 1.0 <00 00 80 3F> 10.0 <00 00 20 41> 1.0 <00 00 80 3F>