The original implementation just printed a mostly information-free message and then went on as if nothing has happened, making it ridiculously easy to write broken code and release it. Changed it to:
* Any VMAbortException will now terminate the game session and go back to the console.
* It will also print a VM stack trace with all open functions, including source file and line numbers pointing to the problem spots. For this the relevant information had to be added to the VMScriptFunction class.
An interesting effect here was that just throwing the exception object increased the VM's Exec function's stack size from 900 bytes to 70kb, because the compiler allocates a separate local buffer for every single instance of the exception object.
The obvious solution was to put this part into a subfunction so that it won't pollute the Exec function's own stack frame. Interesting side effect of this: Exec's stack requirement went down from 900 bytes to 600 bytes. This is still on the high side but already a lot better.
- fixed PARAM_ACTION_PROLOGUE to assign correct types to the implicit pointers. It gave the actual class to the wrong one, which until now did not matter because all functions were using 'Actor', regardless of actual class association.
- fixed the definition of IceChunk and removed some redundant code here. Since A_FreezeDeathChunks already calls SetState, which in turn calls the state's action function, there is no need to call it again explicitly.
- throw a useful exception when a VM abort occurs, the simple enum was incapable of reporting anything more than the barest minimum, which at least for array index out of bounds errors was insufficient.
The current exception mechanism is still insufficient. It really has to report a proper crash location and print a stack trace to the maximum extent possible. Instead it just prints a message and happily goes on. This is not a good solution.
Although this already helps a lot with the messed up code generated for comparisons it's not really a solution for this - it still needs a proper implementation to generate efficient code.
- fixed: When replacing a tentative class, the pointers in the morph objects were not replaced. Instead of adding more ReplaceClassRef methods I chose to integrate this part into the PointerSubstitution mechanism and delete ReplaceClassRef entirely. The code had some oversights anyway that would have caused problems, now that non-actors can be created.
It is utterly pointless to require every function that wants to make a VM call to allocate a new stack first. The allocation overhead doubles the time to set up the call.
With one stack, previously allocated memory can be reused. The only important thing is, if this ever gets used in a multithreaded environment to have the stack being declared as thread_local, although for ZDoom this is of no consequence.
- eliminated all cases where native code was calling other native code through the VM interface. After scriptifying the game code, only 5 places were left which were quickly eliminated. This was mostly to ensure that the native VM function parameters do not need to be propagated further than absolutely necessary.
- added call wrappers and script hooks for all relevant virtuals in AInventory.
- made GetSpeedFactor and GetNoTeleportFreeze entirely scripted because they are too trivial - also do them iteratively, just like HandlePickup, because it's just a better way to do this stuff.
- moved health items to their own file.
- scriptified ScoreItem and MapRevealer whose entire functionality was a small TryPickup method.
- fixed: bit fields in global variables were not correctly written.
This should conclude the inventory cleanup. It is now possible again to find things in there.
It's about time this stuff is getting cleaned up seriously. Both a_pickups.cpp and a_artifacts.cpp are so overstuffed that it has become a chore finding stuff in there.
- removed the native parts of SpecialBlastHandling. Since this is called from the script side and the only remaining native remnant was an empty function it's now 100% scripted.
- cleaned up the virtual function interface of APlayerPawn which still had many virtual declarations from old times when class properties were handled through virtual overrides. None of this makes sense these days anymore.
- Changed the glass shards so that they do not have to override FloorBounceMissile. It was the only place where this was virtually overridden and provided little usefulness.
- made 'out' variables work.
- fixed virtual call handling for HandlePickup.
- added a String class to allow attaching methods to the builtin string type. This works by checking if the left side of the member accessor is a string and just replacing the tyoe in this one place, all the rest is automatic.
- merged the FrontBlock searcher for the Bloodscourge into RoughMonsterSearch. This also fixes the bug that the searcher was not initialized properly for the MageBoss.
- made '->' a single token. Although ZScript does not use it, the parser tends to get confused and fatally chokes on leftover arrows so this ensures more robust error handling.
A few notes:
* this accesses the lines array in sector_t which effectively is a pointer to an array of pointers - a type the parser can not represent. The compiler has no problems with it, so for now it is defined internally.
* array sizes were limited to 65536 entries because the 'bound' instruction only existed as an immediate version with no provisions for larger values. For the static map arrays 65536 is not sufficient so now there are alternative instructions for these cases.
* despite the above, at the moment there is no proper bounds checking for arrays that have no fixed size. To do this, a lot more work is needed. The type system as-is is not prepared for such a scenario.
- fixed: Assignment from a readonly to a read-allowed pointer must be an error.
- made GetDefaultByType a builtin so that it can do proper type assignment to the result, which for a function would be problematic in this case, even if automatic type deduction was implemented. Since this returns the class defaults which are not a real object, the result cannot be subjected to a type cast.
- error out if a type cast of a readonly pointer is attempted.
- fixed: FxBooleanNot could clobber a local variable because it used the source register to manipulate the result.
- fixed issues with the refactoring of the recent commits. This one starts again.
- added builtins for TextureID.
Note about builtins: Currently they are just hacked into the compiler backend. They really should be made part of the respective types to keep matters clean and allow more widespread use of builtins to create more efficient code.
- refactored the ModifyDamage interface to be more scripting friendly.
In general it should be avoided having to call directly into chained inventory functions because they are very problematic and prone to errors. So this got wrapped into a single handler (on AActor, not AInventory!) which will later make it easier to refactor the parameters of ModifyDamage to work better for scripting and avoid the chaining.
Two reasons for this:
1. if this has to be routed through the VM each recursion will cost 1000 bytes of stack space which simply is not good.
2. having the virtual function only care about the item itself but not the entire inventory chain is a lot less error prone for scripting.
Since the scripting interface needs a separate caller function anyway this seemed like a good time to change it. The same will be done for the other chained inventory handlers as well.
- allow switch/case with names.
- fixed break jump target handling for switch/case. This only worked when the break was in the outermost compound statement, those in inner ones were missed.
Interesting tidbit: The damage calculation in P_MinotaurSlam had been incorrect for the Heretic version since the friendly Hexen Dark Servant was added, but nobody ever noticed in 14 years...
- Took the opportunity and fixed the logic for the Skull Rod's rain spawner. The old code which was part of the 3D floor submission was unable to work with portals at all. The new approach no longer tries to hide the dead projectile in the ceiling, it leaves it where it is and changes a few flags, so that its z-position can be used as reference to get the actual ceiling. This works for line portals, but for sector portals still requires some changes to sector_t::NextHighestCeilingAt to work, but at least this can be made to work unlike the old code.
- added names for the player-related translations to A_SetTranslation.
- fixed: Failure to resolve a function argument was checked for, too late.
- made the parameter for A_SetTranslation a name instead of a string, because it is more efficient. We do not need full strings here.
Needless to say, this is simply too volatile and would require constant active maintenance, not to mention a huge amount of work up front to get going.
It also hid a nasty problem with the Destroy method. Due to the way the garbage collector works, Destroy cannot be exposed to scripts as-is. It may be called from scripts but it may not be overridden from scripts because the garbage collector can call this function after all data needed for calling a scripted override has already been destroyed because if that data is also being collected there is no guarantee that proper order of destruction is observed. So for now Destroy is just a normal native method to scripted classes
- scriptified all Effect functions of Fastprojectile's children
- implemented access to class meta data.
- added a VM instruction to retrieve the class metadata, to eliminate the overhead of the function call that would otherwise be needed.
- made GetClass() a builtin so that it can use the new instruction
Important note about this commit: Scriptifying CFlameMissile::Effect revealed a problem with the virtual function interface: In order to work, this needs to be explicitly enabled for each single native class that may be used as a base for a scripted class. Needless to say, this will end up way too much work, as there are over 100 native classes, excluding those which will be scriptified. But in order to fix the problem this partially broken state needs to be committed first.
- fixed: FxAssignSelf did not the correct number of registers for vector operations.
- fixed a few asserts in vector2 instructions.
- turned the virtual AActor::HitFloor method into a flag MF7_SMASHABLE. The only use of this function was to kill Hexen's pottery when they hit the floor, and this looks like something that can be exposed to modders less clumsily.
basicinlines.h is only included in m_fixed.h, while basictypes.h is included only in headers, so it's better to respect this convention. OSX compiles fine also without m_fixed.h, even better.
- renamed APowerMorph::Player to avoid accidental confusion with AActor::player, which in scripting is the same due to case insensitvity.
- renamed save key for above variable.
This prevented any kind of error check on them.
Unfortunately, due to backwards compatibility needs, on DECORATE the missing class may not be fatal so a workaround had to be added to clear those bogus pointers later if they are discovered to be broken.
For ZScript, though, this will result in a compile error, which was the intention behind this change.
It turned out that the Boom method does not work well with portals and fixing it while keeping it doesn't look feasible - the entire approach was bad from the start.
Instead, let's use the same approach as P_XYMovement: Spawn the Lost Soul at the center of the PE, and then use multiple P_TryMoves to get it to its intended location.
This will check all blocking lines, just like Boom did, but it will also properly handle z-positioning and portal transitions.
- added new VARF_Transient flag so that the decision whether to serialize a field does not depend solely on its native status. It may actually make a lot of sense to use the auto-serializer for native fields, too, as this would eliminate a lot of maintenance code.
- defined (u)int8/16 as aliases to the byte and short types (Can't we not just get rid of this naming convention already...?)
- exporting the fields of Actor revealed a few name clashes between them and some global types, so Actor.Sector was renamed to CurSector and Actor.Inventory was renamed to Actor.Inv.
- refactored state bitfield members into a flag word because the address of a bitfield cannot be taken, making such variables inaccessible to scripts.
- actually use PNativeStruct for representing native structs defined in a script.
- fixed flag CVAR access. As it turned out, OP_LBIT is a bit messy to set up properly when accessing integers that may or may not be big endian, so it now uses a shift and bit masking to do its work.
- used the SpawnPlayerMissile call in A_FireBFG to test named arguments.
- fixed: The code generator had no good safeguards for exceeding the maximum amount of registers.
All there was was a handful of pitiful asserts which in production code do nothing at all but generate broken output.
Even worse, the VM was hardwired to at most 255 constants per type per function by storing the constant count in a byte! This has been extended to 65535, but since many instructions only have a byte available for the constant index, a workaround had to be added to do a two-instruction setup if larger indices are needed.
- added new VM instructions to access the constant tables with a variable index.
- refactored VMFunctionBuilder's constant tables so that they are not limited to one entry per value. While this works fine for single values, it makes it impossible to store constant arrays in here.
- implemented method calls from struct instances.
- optimized disassembly of VM call instructions to print the function's name at the end where it is more visible and does not need to be truncated. Also use the printable name for script functions here.
- implemented multiple-return-value assignment. Due to some grammar conflicts the originally intended Lua-inspired syntax of 'a, b = Function()' could not be done, so it's '[a, b] = Function()'
- made APlayerPawn::PlayAttacking(2) virtual script functions so that mods have better control over player animations. Note that these have no native base so they skip the templated interface for managing virtual functions.
- added a new type 'NativeStruct'. This will be used for types that cannot be instantiated, and is also needed to cleanly handle many internal types that only can exist as reference.
- changed Dehacked weapon function lookup to check the symbol table instead of directly referencing the VM functions. Once scriptified these pointers will no longer be available.
- removed all special ATAGs from the VM. While well intentioned any pointer tagged with them is basically unusable because it'd trigger asserts all over the place.
- scriptified A_Punch for testing pass-by-reference parameters and stack variables.
- gave OP_CONCAT some sane semantics. The way this was defined, by specifying the source operands as a range of registers instead of a pair like everything else made it completely useless for the task at hand.
- changed formatting for floats to %.5f which for normal output in a game makes more sense. For special cases there should be a special formatting function for ints and floats that can do more specialized conversions.
- make the pointer to string cast a bit more useful by using the actual object's type rather than 'Object' which can be a great asset when debugging.
- fixed a few bad asserts.
- fixed code generation for using local variables as array index. This must use a different register for the array element offset because the original register may not be overwritten.
- instead add a list of SpecialInits to VMScriptFunction so this can be done transparently when setting up and popping the stack frame. The only drawback is that this requires permanent allocation of stack objects for the entire lifetime of a function but this is a relatively small tradeoff for significantly reduced maintenance work throughout.
- removed most #include "vm.h", because nearly all files already pull this in through dobject.h.
- fixed several places in the code generator that did not consider locked registers for local variables: array indices, abs and floating point builtin functions.
- added some debug aids to the bounds opcode. Just triggering an exception here which loses all relevant info is perfectly useless in a debug situation.
- added a DActorIterator class.
- fixed: It was not possible to have functions of the same name in two different classes because the name they were searched for was not qualified by the class. Changed so that the class name is included now, but to avoid renaming several hundreds of functions all at once, if the search fails, it will repeat with 'Actor' as class name.
This commit contains preparations for scriptifying Hexen's Dragon, but that doesn't work yet so it's not included.
- preserve a state's source line information for the postprocessing phase so that the checker can output more useful information.
- added missing check for weapon psprites to DPSprite::SetState.
- added state usage specifiers to Actor and Inventory. The states in these classes must be set to full access so that any existing mod can link to them.
This appears to be the only case where an actor was set to a state owned by a completely unrelated actor which would present some problems with state owner checking in AActor::SetState, so let's better get rid of it ASAP.
I believe the only reason this wasn't changed when all actors were exported 8 years ago was that old binary DEHSUPP lump.
This could cause problems with functions that take states as parameters but use them to set them internally instead of passing them through the A_Jump interface back to the caller, like A_Chase or A_LookEx.
This required some quite significant refactoring because the entire state resolution logic had been baked into the compiler which turned out to be a major maintenance problem.
Fixed this by adding a new builtin type 'statelabel'. This is an opaque identifier representing a state, with the actual data either directly encoded into the number for single label state or an index into a state information table.
The state resolution is now the task of the called function as it should always have remained. Note, that this required giving back the 'action' qualifier to most state jumping functions.
- refactored most A_Jump checkers to a two stage setup with a pure checker that returns a boolean and a scripted A_Jump wrapper, for some simpler checks the checker function was entirely omitted and calculated inline in the A_Jump function. It is strongly recommended to use the boolean checkers unless using an inline function invocation in a state as they lead to vastly clearer code and offer more flexibility.
- let Min() and Max() use the OP_MIN and OP_MAX opcodes. Although these were present, these function were implemented using some grossly inefficient branching tests.
- the DECORATE 'state' cast kludge will now actually call ResolveState because a state label is not a state and needs conversion.
Now even in DECORATE it is possible to report most cases in which user variables are accessed from non-item states as an error. This will report all states which can be traced by a direct link from a special state label. It will not find states that only get used via A_Jump etc.
- since we now look for fields in the base class first the restriction check is no longer needed as it was for a different mode of looking up the identifier.
- In DECORATE we do not need to bother with non-action functions. Non-action functions cannot be defined from DECORATE so there's no need to check if we are in one.
- make the warning for unsafe access a debug message because this can affect legitimate code.
- Replaced GTK/OS X (note different from Cocoa) clipboard code with SDL clipboard API.
- Removed requirement to link to GTK in order to compile with GTK support.
- GTK is no longer init'd if the GTK IWAD picker is not used.
- Our usage of GTK is such that the dynamic loader can work with both GTK2 and GTK3 depending on what's installed.
- Since we're accumulating a lot of library loaders I've built a generic interface as FModule which replaces TOptWin32Proc and the loaders in the OpenAL and Fluidsynth code.
- fixed creation of direct function invocations on a state line. In order to receive the implicit arguments this needs to be wrapped into a compound statement so that the local variable getter works.
The proper setup for such classes was only done in CreateDerivedClass, but not in FindClassTentative itself. This extends CreateDerivedClass to allow it to create a class without fully initializing it.
