1. Introduction to Half Life 2 Modding ● Seminar Seven – The story so far: ● Creating a mod via Source SDK ● Introduction to Hammer ● Hammer techniques ● Importing custom art content – This week: ● Mod organisation and starting to code – Homework: ● See how much you can break the code

2. Mod Layout ● Folder structure – Bin – contains all DLL files – Cfg – contains all configuration files – Maps – all files relating to maps (BSP, sound caches, nav graphs) – Materials – all texture / material files (VMT / VTF) – Media – video to play at game startup – Models – all model files (MDL, PHY, VVD and VTX) – Resource – files that dictate visual appearance (HUD, menus). – Scripts – files that control everything else (weapons, audio effects etc) – Shaders – compiled shader files (VCS) – both pixel and vertex – Sound – all sound files (MP3 / WAV)

3. Altering the visual style ● ClientScheme.res – Controls menu styles ● Font type, size and colour ● Setting background image – Insert VTF/VMT into materials/console ● The VMT shader is “UnlitGeneric” – Create / modify scripts/ChapterBackgrounds.txt ● Enter name of VMT file, minus extension and location. ● Altering the HUD – Core file is scripts/HudLayout.res

4. Overview of code ● The code base is divided into two sections – Client and Server ● Client controls rendering and visual effects ● Server controls game logic (it does the 'thinking') – There is communication between the two sections and some bits of code appear in both! ● The code base is not a simple beast! – Over a million lines of code, only 15% of which are comments! – The Hidden has added 20,000 lines of new code and it's still not done!

5. Working with the code ● The current code base can be opened in either Visual Studio 2003 or 2005. – It's currently easier to work in 2005! ● It contains two projects, client_sdk and hl – client_sdk is all client code – hl is all server code ● Some code is found in both projects – Open weapon_rpg.cpp – find it in HL2MP / weapons on the sidebar. ● Note the series of statements such as #ifdef CLIENT_DLL.

6. Modifying the code ● With weapon_rpg.cpp still open – Find the line that reads: #define RPG_SPEED 1500 – Modify the value to something significantly different ● 500 or 2500 would be good! – Compile (Ctrl-Shift-B or Build | Build Solution) ● This will take some time the first time you do it! ● You have now successfully created a modification for HL2 – simple as it may be!

7. Adding code ● Now we'll look at adding an item to the code – We'll copy an existing weapon ● This requires new code and new items in the mod folder – Open weapon_smg1.cpp ● Note there is no matching header file (this makes our life a bit easier) ● Select all the code and copy it (Ctrl-A then Ctrl-C) – Add a new folder to the client project – Right Click 'client' – Add | New Folder ● Add a new item to that folder – Right Click folder – Add | Add New Item – Select C++ file, enter a file name (weapon_*.cpp), create a new folder under game_shared – use that as the save location

8. Adding code (cont.) ● In the empty window, paste the code we just copied ● Now we need to rename the class – find a bit of code that says the class name (CweaponSMG1) – Copy the WeaponSMG1 part (not the C!) – Use Find and Replace (Ctrl-H) ● Enter WeaponSMG1 as the Find and WeaponSMGMine as the Replace – press Replace All. ● Final stage in code – add the new file to the server project!

9. Adding code (cont.) ● Add a new folder to the 'hl' project ● Rather than adding a new item, add an existing one and find the weapon_smg2.cpp file we just created. – See now why we put the file in game_shared? ● One last change in code – line 85 ( LINK_ENTITY_TO_CLASS ) and 86, change weapon_smg1 to weapon_smg2 – This tells the game where to look for the script information and stops it getting confused

10. Finishing off the weapon ● Find weapon_smg1.txt in the mod scripts folder – Copy and paste it – Rename it to weapon_smg2.txt ● Open weapon_smg2.txt – Change bucket_position to 2 – Play with the values (alter the clip_size, change the view model etc) ● Boot up the game and see your changes – Use ‘give weapon_smg2’ to play with your new weapon.