Before the change campaign bonus selection screen had inconsistent
overflow behaviour for difficulty selection:
```
0 1 2 3 4 | available buttons: '-' to decrease
^ | '+' to increase
```
Before the change:
1. If we click '+' 5 times we will end up on difficulty=4 (ok, saturated).
2. If we click '-' 5 times we will end up on difficulty=1 (unexpected, wrap around).
After the change:
1. If we click '+' 5 times we will end up on difficulty=4 (saturated).
2. If we click '-' 5 times we will end up on difficulty=0 (saturated).
The inconsistency happens because `difficulty` variable has `ui8` type
and server uses `difficulty = vstd::abetween(difficulty, 0, 4)` to
implement the saturation.
For large positive values saturation works as expected:
vstd::abetween(difficulty=5, 0, 4) -> 4
For small values it does not:
vstd::abetween(difficulty=-1, 0, 4) -> 4
The change makes client to avoid using negative values.
* Made most Handlers derived from CHandlerBase and moved service API there.
* Declared existing Entity APIs.
* Added basic script context caching
* Started Lua script module
* Started Lua spell effect API
* Started script state persistence
* Started battle info callback binding
* CommitPackage removed
* Extracted spells::Caster to own header; Expanded Spell API.
* implemented !!MC:S, !!FU:E, !!FU:P, !!MA, !!VR:H, !!VR:C
* !!BU:C, !!BU:E, !!BU:G, !!BU:M implemented
* Allow use of "MC:S@varName@" to declare normal variable (technically v-variable with string key)
* Re-enabled VERM macros.
* !?GM0 added
* !?TM implemented
* Added !!MF:N
* Started !?OB, !!BM, !!HE, !!OW, !!UN
* Added basic support of w-variables
* Added support for ERM indirect variables
* Made !?FU regular trigger
* !!re (ERA loop receiver) implemented
* Fixed ERM receivers with zero args.
Disabled the following (for MSVC only) that couldn't (or shouldn't) be fixed.
4003: not enough actual parameters for macro 'identifier'
4250: 'class1' : inherits 'class2::member' via dominance
4251: 'type' : class 'type1' needs to have dll-interface to be used by clients of class 'type2'
4275: non dll-interface class 'type1' used as base for dll-interface class 'type2'
* use smart pointers for almost all widget fields
* use SDL2 texture for cursor
* a lot af small tweaks and formatting
* removed CompImage class, it is actually useless as long as regular SDLImage support margins
* CGuiHandler: use smart pointers for [push|pop]Int
We need to make sure it's not stay active during gameplay.
Proper fix would require actually removing menu interface from GH, but then GH needs refactoring too.
* Changed most gui classes to use shared pointers
* Store and use IImage as shared_ptr
* CSpellWindow redesign
* AdventureMapClasses cleanup
* CLabel: store background as smart pointer
* Store CObjectList items as smart pointers
* Removed destroy function of list item
* Store toggle buttons as smart pointers
* Use CComponent as smart pointer
* Attempt to fix artifact merchant drawing
New features for players:
* Loading for multiplayer. Any save could be used for multiplayer.
* Restart for multiplayer. All clients will restart together.
* Loading from single save.
* Hotseat mixed with network game. Multiple players per client.
* Now connection to server could be cancelled.
* Return to menu on disconnections instead of crashes.
* Restoring of last selected map, save or campaign on next run.
TLDR on important changes in engine code:
* UI: work with server separated from UI
* UI: all explitic blitting replaced with IntObject's
* UI: all new code use smart pointers instead of DISPOSE
* Gameplay always start through lobby controlled by server.
* Threads receiving netpacks now shared for lobby and gameplay.
* Campaigns: heroes for crossover now serialized as JsonNode.
