; Expedition lifecycle and fixed 35 Hz simulation. No external game runtime.
HFPlaySound PROC channel:DWORD
    cmp hfSoundReady,0
    je @F
    mov eax,channel
    cmp eax,6
    jae @F
    invoke mciSendStringA,hfSndPlays[eax*4],0,0,0
@@:
    ret
HFPlaySound ENDP

HFLoad PROC uses esi edi
    cmp hfLoaded,1
    je hf_load_ok
    xor esi,esi
hf_load_next:
    invoke LoadAnimPack3D,hfPacks[esi*4],hfPaths[esi*4]
    test eax,eax
    jz hf_load_failed
    inc esi
    cmp esi,HF_PACK_COUNT
    jb hf_load_next
    ; Dedicated texture slots, never overwrite casino materials.
    mov esi,hfMaterials.pixels
    mov edi,OFFSET texturesBuffer+HF_WALL*65536
    mov ecx,12*128*128
    cld
    rep movsd
    mov hfLoaded,1
hf_load_ok:
    mov eax,1
    ret
hf_load_failed:
    call FreeHellFPS3D
    xor eax,eax
    ret
HFLoad ENDP

FreeHellFPS3D PROC uses esi
    xor esi,esi
@@:
    invoke FreeAnimPack3D,hfPacks[esi*4]
    inc esi
    cmp esi,HF_PACK_COUNT
    jb @B
    mov hfLoaded,0
    invoke mciSendStringA,OFFSET hfMusicClose,0,0,0
    xor esi,esi
@@:
    invoke mciSendStringA,hfSndCloses[esi*4],0,0,0
    inc esi
    cmp esi,6
    jb @B
    mov hfSoundReady,0
    ret
FreeHellFPS3D ENDP

HFReset PROC uses esi edi ebx
    mov esi,OFFSET hfMapTemplate
    mov edi,OFFSET hfMap
    mov ecx,256
    cld
    rep movsd
    xor eax,eax
    mov edi,OFFSET hfBolts
    mov ecx,SIZEOF hfBolts/4
    rep stosd
    mov edi,OFFSET hfImpacts
    mov ecx,SIZEOF hfImpacts/4
    rep stosd
    mov edi,OFFSET hfItemTaken
    mov ecx,HF_ITEMS
    rep stosd
    mov esi,OFFSET hfEnemySeeds
    mov edi,OFFSET hfEnemies
    mov ebx,HF_ENEMIES
hf_reset_enemy:
    lodsd
    mov [edi].HFEnemy.x,eax
    lodsd
    mov [edi].HFEnemy.y,eax
    lodsd
    mov [edi].HFEnemy.kind,eax
    mov eax,hfMonsterHP[eax*4]
    mov [edi].HFEnemy.hp,eax
    mov [edi].HFEnemy.cooldown,35
    mov [edi].HFEnemy.pose,0
    mov [edi].HFEnemy.timer,0
    mov [edi].HFEnemy.awake,0
    add edi,SIZEOF HFEnemy
    dec ebx
    jnz hf_reset_enemy
    mov hfState,0
    mov hfHealth,100
    mov hfArmor,0
    mov hfBullets,80
    mov hfShells,0
    mov hfWeapon,0
    mov hfHasShotgun,0
    mov hfKey,0
    mov hfSecrets,0
    mov hfKills,0
    mov hfTicks,0
    mov hfAccumulator,0
    mov hfCooldown,0
    mov hfFlash,0
    mov hfHurt,0
    mov hfDoorMask,0
    mov hfAwarded,0
    mov hfFireHeld,0
    mov hfFirePending,0
    mov hfUsePending,0
    mov playerX,3*FP_1+FP_HALF
    mov playerY,26*FP_1+FP_HALF
    mov playerAngle,0
    mov worldMap3D,OFFSET hfMap
    mov hallLevel3D,99
    mov floorTexture3D,HF_FLOOR
    mov viewEye3D,FP_1
    mov viewCeiling3D,FP_1*5/2
    mov outdoorRender3D,0
    mov viewHorizon3D,HALF_H
    mov engineMode,MODE_HELL_FPS
    mov hfMessage,OFFSET hfWelcomeText
    mov hfMessageTime,210
    call ClearKeys3D
    call UpdateCamera3D
    call HFBuildFlow
    ret
HFReset ENDP

BeginHellFPS3D PROC uses esi
    call HFLoad
    test eax,eax
    jnz @F
    invoke CopyString3D,OFFSET hfMissingText,OFFSET flashMessage
    mov flashTimer,180
    ret
@@:
    mov eax,playerX
    mov hfOldX,eax
    mov eax,playerY
    mov hfOldY,eax
    mov eax,playerAngle
    mov hfOldAngle,eax
    mov eax,worldMap3D
    mov hfOldMap,eax
    mov eax,floorTexture3D
    mov hfOldFloor,eax
    mov eax,hallLevel3D
    mov hfOldLevel,eax
    mov eax,viewEye3D
    mov hfOldEye,eax
    mov eax,viewCeiling3D
    mov hfOldCeiling,eax
    call StopTowerMusic
    call StopJukeboxTrack3D
    invoke PlayCasinoSound3D,0,0,0
    invoke mciSendStringA,OFFSET hfMusicOpen,0,0,0
    mov hfMusicError,eax
    mov hfLastVolume,-1
    call HFUpdateMusicVolume
    invoke mciSendStringA,OFFSET hfMusicPlay,0,0,0
    or hfMusicError,eax
    mov hfSoundFailures,0
    xor esi,esi
hf_open_sound:
    invoke mciSendStringA,hfSndOpens[esi*4],0,0,0
    test eax,eax
    jz @F
    inc hfSoundFailures
@@:
    inc esi
    cmp esi,6
    jb hf_open_sound
    mov hfSoundReady,1
    call HFReset
    ret
BeginHellFPS3D ENDP

LeaveHellFPS3D PROC uses esi
    mov eax,hfOldX
    mov playerX,eax
    mov eax,hfOldY
    mov playerY,eax
    mov eax,hfOldAngle
    mov playerAngle,eax
    mov eax,hfOldMap
    mov worldMap3D,eax
    mov eax,hfOldFloor
    mov floorTexture3D,eax
    mov eax,hfOldLevel
    mov hallLevel3D,eax
    mov eax,hfOldEye
    mov viewEye3D,eax
    mov eax,hfOldCeiling
    mov viewCeiling3D,eax
    mov hfFireHeld,0
    mov hfFirePending,0
    mov engineMode,MODE_WALK
    mov paused3D,0
    invoke mciSendStringA,OFFSET hfMusicClose,0,0,0
    xor esi,esi
@@:
    invoke mciSendStringA,hfSndCloses[esi*4],0,0,0
    inc esi
    cmp esi,6
    jb @B
    mov hfSoundReady,0
    call ClearKeys3D
    call UpdateCamera3D
    ret
LeaveHellFPS3D ENDP

HFUpdateMusicVolume PROC
    mov eax,settingsVolume
    cmp eax,hfLastVolume
    je @F
    mov hfLastVolume,eax
    imul eax,HF_MUSIC_SCALE
    invoke FormatNumber,eax,OFFSET hfNumber
    invoke CopyCString,OFFSET hfVolumeCommand,OFFSET hfVolumePrefix
    invoke AppendCString,OFFSET hfVolumeCommand,OFFSET hfNumber
    invoke mciSendStringA,OFFSET hfVolumeCommand,0,0,0
    mov hfVolumeError,eax
@@:
    ret
HFUpdateMusicVolume ENDP

HandleHellFPS3D PROC uses ebx
    call HFUpdateMusicVolume
    cmp hfState,0
    je hf_handle_play
    invoke Pressed3D,0Dh
    test eax,eax
    jz hf_handle_done
    cmp hfState,1
    jne hf_handle_exit
    call HFReset
    ret
hf_handle_exit:
    call LeaveHellFPS3D
    ret
hf_handle_play:
    call HandlePlayerInput
    invoke Pressed3D,31h
    test eax,eax
    jz @F
    mov hfWeapon,0
@@:
    invoke Pressed3D,32h
    test eax,eax
    jz @F
    cmp hfHasShotgun,0
    je @F
    mov hfWeapon,1
@@:
    invoke Pressed3D,45h
    or hfUsePending,eax
    mov eax,mouseClick3D
    or hfFirePending,eax
    mov mouseClick3D,0
    mov eax,deltaTime3D
    imul eax,35
    add hfAccumulator,eax
hf_handle_tick:
    cmp hfAccumulator,1000
    jb hf_handle_done
    sub hfAccumulator,1000
    call HFTick
    cmp hfState,0
    je hf_handle_tick
    mov hfAccumulator,0
hf_handle_done:
    ret
HandleHellFPS3D ENDP