; Deterministic avenue traffic; stationary cars stay near the curb.
AnimateCityCars3D PROC uses ebx esi edi
    local trafficClock:DWORD
    mov eax, cityClock3D
    ; A red-light interval lets the protagonist cross from the alley.
    ; Resume from the stopped position instead of jumping forward in world space.
    cmp eax,7000
    jb city_traffic_clock_ready
    cmp eax,8400
    jae city_traffic_wait
    sub eax,7000
    mov ebx,eax
    imul eax,eax
    xor edx,edx
    mov ecx,2800
    div ecx
    sub ebx,eax
    lea eax,[ebx+7000]
    jmp city_traffic_clock_ready
city_traffic_wait:
    cmp eax,14300
    jae city_traffic_resume
    mov eax,7700
    jmp city_traffic_clock_ready
city_traffic_resume:
    cmp eax,15700
    jae city_traffic_cruise
    sub eax,14300
    imul eax,eax
    xor edx,edx
    mov ecx,2800
    div ecx
    add eax,7700
    jmp city_traffic_clock_ready
city_traffic_cruise:
    sub eax,7300
city_traffic_clock_ready:
    mov trafficClock,eax
    mov ecx, FP_1/2500
    mul ecx
    mov ecx, 26*FP_1
    div ecx
    add edx, 3*FP_1
    mov cityObjects3D[CITY_TRAFFIC_EAST*SIZEOF CityProp3D].posX, edx
    mov eax, trafficClock
    mov ecx, FP_1/2900
    mul ecx
    mov ecx, 26*FP_1
    div ecx
    mov eax, 29*FP_1
    sub eax, edx
    mov cityObjects3D[CITY_TRAFFIC_WEST*SIZEOF CityProp3D].posX, eax
    mov esi, CITY_FIRST_CAR
city_car_view:
    cmp esi, 12
    je city_car_next
    cmp esi, 13
    je city_car_next
    imul edi, esi, SIZEOF CityProp3D
    mov eax, playerX
    sub eax, cityObjects3D[edi].posX
    mov edx, playerY
    sub edx, cityObjects3D[edi].posY
    cmp esi, CITY_TRAFFIC_WEST
    jne @F
    neg eax
    neg edx
@@:
    push eax
    push edx
    test eax, eax
    jns @F
    neg eax
@@:
    test edx, edx
    jns @F
    neg edx
@@:
    lea ebx, [edx*2]
    cmp eax, ebx
    ja city_car_longitudinal
    lea ebx, [eax*2]
    cmp edx, ebx
    ja city_car_lateral
    pop edx
    pop eax
    mov ebx, 1
    test eax, eax
    jle @F
    mov ebx, 3
@@:
    test edx, edx
    jns city_car_set
    mov ebx, 7
    test eax, eax
    jle city_car_set
    mov ebx, 5
    jmp city_car_set
city_car_longitudinal:
    pop edx
    pop eax
    xor ebx, ebx
    test eax, eax
    jle city_car_set
    mov ebx, 4
    jmp city_car_set
city_car_lateral:
    pop edx
    pop eax
    mov ebx, 2
    test edx, edx
    jns city_car_set
    mov ebx, 6
city_car_set:
    mov eax, cityObjects3D[edi].frame
    and eax, 8
    add eax, ebx
    mov cityObjects3D[edi].frame, eax
city_car_next:
    inc esi
    cmp esi, CITY_TRAFFIC_WEST+1
    jb city_car_view
    ret
AnimateCityCars3D ENDP

; Pedestrians follow continuous curb routes, independently of rendering FPS.
AnimateCityPedestrians3D PROC uses ebx esi edi
    local walkingFrame:DWORD
    xor esi, esi
city_ped_route:
    imul ebx, esi, SIZEOF CityWalkRoute3D
    add ebx, OFFSET cityWalkRoutes3D
    mov eax, cityClock3D
    add eax, [ebx].CityWalkRoute3D.phaseOffset
    xor edx, edx
    mov ecx, [ebx].CityWalkRoute3D.halfPeriod
    shl ecx, 1
    div ecx
    mov eax, edx
    mov edx, [ebx].CityWalkRoute3D.firstFrame
    mov walkingFrame, edx
    cmp eax, [ebx].CityWalkRoute3D.halfPeriod
    jb city_ped_forward
    sub eax, [ebx].CityWalkRoute3D.halfPeriod
    add walkingFrame, 8
    mov ecx, [ebx].CityWalkRoute3D.maxX
    sub ecx, [ebx].CityWalkRoute3D.minX
    mul ecx
    div [ebx].CityWalkRoute3D.halfPeriod
    neg eax
    add eax, [ebx].CityWalkRoute3D.maxX
    jmp city_ped_position
city_ped_forward:
    mov ecx, [ebx].CityWalkRoute3D.maxX
    sub ecx, [ebx].CityWalkRoute3D.minX
    ; Keep the high product: route distance * milliseconds exceeds 32 bits.
    mul ecx
    div [ebx].CityWalkRoute3D.halfPeriod
    add eax, [ebx].CityWalkRoute3D.minX
city_ped_position:
    imul edi, [ebx].CityWalkRoute3D.objectIndex, SIZEOF CityProp3D
    mov cityObjects3D[edi].posX, eax
    mov eax, [ebx].CityWalkRoute3D.curbY
    mov cityObjects3D[edi].posY, eax
    mov eax, cityClock3D
    add eax, [ebx].CityWalkRoute3D.phaseOffset
    xor edx, edx
    div [ebx].CityWalkRoute3D.poseMs
    and eax, 7
    add eax, walkingFrame
    mov cityObjects3D[edi].frame, eax
    inc esi
    cmp esi, CITY_PEDESTRIAN_COUNT
    jb city_ped_route
    ret
AnimateCityPedestrians3D ENDP