Code structure

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Revision as of 07:29, 2 May 2010 by Warmonger (talk | contribs) (Main purposes of lib)
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The code of VCMI is divided into several main parts: client, server, lib and AIs, each one in a separate binary file.

Structure of client

Main purposes of client

Client is responsible for:

  • displaying state of game to human player
  • capturing player's actions and sending requests to server
  • displaying changes in state of game indicated by server

Rendering of graphics

Rendering of graphics relies heavily on SDL. Currently we do not have any wrapper for SDL internal structures and most of rendering is about blitting surfaces using SDL_BlitSurface. We have a few function that make rendering easier or make specific parts of rendering (like printing text). They are places in client/SDL_Extensions and client/SDL_Framerate (the second one contains code responsible for keeping appropriate framerate, it should work more smart than just SDL_Delay(miliseconds)). In rendering, Interface object system is quite helpful. Its base is CIntObject class that is basically a base class for our library of GUI components and other objects.

Primitive controls

VCMI provides a set of controls a window can be build from. We have already written basic counterparts of most of standard controls like buttons, labels etc. Here is a list of them:

  • AdventureMapButton - standard button class for general use (its name is after its first application). Optimized for buttons having standard .DEF graphics. When it's pressed, all functions from its callback field are called.
  • CHighlightableButton - basically a checkbox. Has two callbacks: one for selecting and one for deselecting. It inherits from AdventureMapButton because most of graphics handling is common/
  • CHighlightableButtonsGroup - a radio button group. It consist of many CHighlightableButtons. Functions from onChange are called when selection is changed (the parameter is the ID of selected button).
  • CSlider - a typical slider.
  • CLabel - a label with custom font and color. It does nothing interesting.
  • CPicture - any bitmap.
  • CTextInput - a textbox.
  • CGStatusBar - a statusbar for general use.

Adventure map





Animations of creatures

All animations of creatures in a battle are handled by storing currently displayed animations in pendingAnims vector. When server tells that an event requiring animation happens, info about it is added to pendingAnims. Every animation needs to be initialized (what indicates that this animation has started). show() function tries to initialize all not initialized animations every frame until it succeeds. Then nextFrame call-ins are called until animation removes itself from pendingAnims. During initialization it is checked if this animation can be played now or we must wait.

Showing sequence of stacks, obstacles and wall pieces

Firstly, all dead stacks are printed on the screen. Then alive stacks, obstacles and wall pieces are printed in order of appearance (number of hex they are placed on). This algorithm works fairly well if no creatures move, but due to the fact that while a creature is moving, its position is the destination, not the hex they are walking on, sometimes it makes some graphical glitches that are not easy to fix.

Structure of server

Main purposes of server

Server is responsible for:

  • maintaining state of the game
  • handling requests from all clients participating in game
  • informing all clients about changes in state of the game that are visible to them

Structure of lib

Main purposes of lib

Lib is responsible for:

  • handling Heroes III's files (.lod, txt setting files)
  • storing information common to server and client like state of the game
  • managing armies, buildings, artifacts, spells, bonuses and other game objects
  • handling general game mechanics and related actions

Structure of AI (GeniusAI)


How these parts are connected