Add a few more header elements

parser/src/header.rs

@@ -23,6 +23,8 @@ impl Default for Player {
 /// `#RANK [0-3]`. Defines the judge difficulty.
 ///
 /// We follow LR2 convention here, so Rank is 0,1,2,3
+#[derive(FromRepr, Debug, PartialEq, Clone)]
+#[repr(u8)]
 pub enum Rank {
     VeryHard, // RANK 0, +-8ms
     Hard,     // RANK 1, +- 15ms
@@ -54,6 +56,10 @@ pub enum JudgeRankType {
     /// Exrank is also weird. It allows the timing window of the chart to be changed
     /// during play.
     ///
+    /// The string represents the identifier (In the example "cc" or "aa")
+    /// and the f32 represents the rank as a percentage of rank 2.
+    ///
+    /// # Example
     /// To steal from hitkey as an example.
     /// ```
     /// #RANK 2
@@ -63,9 +69,6 @@ pub enum JudgeRankType {
     /// ```
     /// Would result in the timing window for measure 114 changing to DEFEXRANK 48,
     /// and then going back to DEFEXRANK 100 at the end of the measure.
-    ///
-    /// The string represents the identifier (In the example "cc" or "aa")
-    /// and the f32 represents the rank as a percentage of rank 2.
     Exrank(String, f32),
 }
 
@@ -246,8 +249,14 @@ impl Default for ConstantBPM {
 /// This operates on Channel #xxx08.
 ///
 /// This command allows the chart designer to describe BPM changes.
-/// For example,
 ///
+/// Negative BPMs are allowed, and in general are expected to make the chart scroll _backwards_.
+///
+/// For more info, see https://hitkey.nekokan.dyndns.info/exbpm-object.htm
+///
+/// In parsing, we expect to parse the identifier to the string, and the bpm to the float.
+///
+/// # Example
 /// ```
 /// #BPMAA 256
 /// #BPMBB 155.5
@@ -256,12 +265,6 @@ impl Default for ConstantBPM {
 ///
 /// This defines the BPM AA to be 256, the BPM BB to be 155.5 and says where to use it
 /// in the chart itself.
-///
-/// Negative BPMs are allowed, and in general are expected to make the chart scroll _backwards_.
-///
-/// For more info, see https://hitkey.nekokan.dyndns.info/exbpm-object.htm
-///
-/// In parsing, we expect to parse the identifier to the string, and the bpm to the float.
 pub struct ExBPM(String, f32);
 
 /// Represent the multiple types of BPM as enum variants.
@@ -270,5 +273,123 @@ pub enum BPM {
     Extended(ExBPM),
 }
 
-/// `#STOP[01-ZZ] n`
+/// `#STOP[01-ZZ] n`, DDR Style stops!
+///
+/// Operates on Channel #xxx09
+///
+/// A STOP sequence is an object which stops scrolling of the chart for a defined
+/// period of time.
+/// Once the time is elapsed, the chart will resume normal scrolling.
+///
+/// We should treat a `#STOPxx 1` as defining a STOP for 1/192nd of a note in 4/4.
+/// It's also important to note that we use the BPM _at time of stop_.
+///
+/// Implementing this in game is a bit tricky, due to the #xxx02 command which adjusts
+/// how long a measure is.
+///
+/// Decimal stops have their fractional part dropped.
+///
+/// A negative STOP duration is weirdly defined. For LR2 it applies "-1" and causes it
+/// to skip some amount of notes.
+/// Generally, it's ignored.
+///
+/// # Example
+///
+/// ```
+/// #STOP11 96
+/// #STOP22 96
+/// #00109:0011
+/// #00202:0.5
+/// #00209:0022
+/// ```
+///
+/// Reading BMS is awkward, so think about each line here being split like so
+/// [AAA][BB]:[CC]
+/// Where AAA is the measure, BB is the command we're executing on that measure
+/// and CC is the "operand" to that command.
+///
+/// Defines STOP 11 as having a length of 192nd note * 96, and so does STOP 22.
+/// #00109:0011 says to do STOP 11 on measure 1
+/// #00209:0022 says to do STOP 22 on measure 2
+///
+/// An example of a 1 second stop
+/// ```
+/// #BPM 60 // Set BPM to 60
+/// #STOP33 48 // 48 * 1/192 stop length
+/// #00109:33
+/// ```
+///
+/// If a STOP and a note are on the same time, the note plays first then timing changes.
+/// If a STOP and a BPM change are on the same time, then BPM changes then STOP is applied.
+///
+/// For some more examples, please refer to
+/// https://hitkey.bms.ms/cmds.htm#STOP
 pub struct Stop(String, u32);
+
+/// `#LNTYPE[0-3]`. Long Note type
+///
+/// LNType is a field kept for backwards compatibility, as it's no longer needed
+/// with the advent of LNOBJ.
+///
+/// LnType 1 is what we hope we see. We should probably just parse error and
+/// tell the user we're ignoring their chart if it's LNType 2 or 3.
+///
+/// This is omissble.
+pub struct LNType(u8);
+
+/// `#LNOBJ xx`
+///
+/// This is RDM type LNs. They have sounds on keyup and they're annoying.
+///
+/// TODO: Explain how this works better rather than handwaving it.
+pub struct LNObj(u32);
+
+/// `#WAV[00-ZZ] filename`
+///
+/// One of the most common commands! This defines the sound files that we actually
+/// play!
+///
+/// A single file is assignable to two or more indexes. This is used for polyphony.
+///
+/// "Alternate search" is expected now. If we cant find example.wav we should search
+/// for example.ogg, example.mp3 etc
+///
+/// Certain channels are assigned, to certain things.
+///
+/// - `#xxx01` is assigned to the BGM.
+/// - `#xxx11-19` is assigned to P1 notes
+/// - `#xxx21-29` is assigned to P2 notes
+/// - `#xxx31-39` is assigned to P1 _invisible_ notes
+/// - `#xxx41-49` is assigned to P2 _invisible_ notes
+/// - `#xxx51-59` are assigned to P1 LNs.
+/// - `#xxx61-69` are assigned to P2 LNs.
+/// - `#xxxD1-D9` are assigned to P1 landmines.
+/// - `#xxxE1-E9` are assigned to P2 landmines.
+///
+/// For more info see https://hitkey.bms.ms/cmds.htm#WAVXX
+/// as this is one of the most complex commands we encounter
+pub struct Wav(u32, String);
+
+/// `#BMP[00-ZZ] filename`
+///
+/// Image resources. And Also video!
+///
+/// Interesringly, certain channels are assigned to certain images.
+///
+/// - `#xxx04` is the base bga
+/// - `#xxx06` is the POOR image
+/// - `#xxx07` is the "BGA Layer"
+/// - `#xxx0A` is the "BGA Layer 2"
+///
+/// Videos can be used in any of these indexs. In general, we should expect video playback
+/// to only be possible on #xxx04.
+///
+/// When a video is being played, we should apply layers/miss animation etc overtop.
+///
+/// If nothing is found in channel `#xxx04/06/07` we should display just a black image.
+///
+/// We should support as many image formats as is reasonable.
+/// PNG, JPG, GIF, TGA, DDS are all common.
+///
+/// Like with #WAV we should support alternate search. So try PNG then JPEG then GIF etc.
+pub struct Bmp(u32, String);