Objectives:
(1) Do not do unnecessary work: if you want 60 FPS, then any additional screen updates are worthless
(2) Do not check every timing to see if any is due to execute
So my thought is to maintain a Sorted Event Timing Array. Here is a quick example:
Code: Select all
const TILEW = 5
const TILEH = 5
const SCRW = 1280
const SCRH = 600
dim shared as integer map(100,100,5)
dim shared as double starttime, endtime
' PQ_TE = Sorted Array/Stack for Timer Event Stack
dim shared as double PQ_TE(1000,2)
' #0 = Event Time
' #1 = Event Type
' #2 = Event Info (not used in this example...)
' TE_pntr = Timer Event stack pointer
dim shared as integer TE_pntr
declare sub Refreshscreen
declare sub DrawGrid
declare function PQ_TE_Add(ByVal newtime as double, byval event as double) as integer
declare function PQ_TE_Del(ByVal thisOne as integer) as integer
screenres SCRW,SCRH,32,2 'set up 2 video pages (#0 visible, #1 working)
dim shared as integer FPS, LPS, desiredFPS, Loops, Frames
dim shared as double TimeStart, OldTime, RefreshTime, EstRefreshdelay, Lastframe
' Initialize Main Loop
locate 50,20 : input "Desired FPS :";desiredFPS
RefreshTime = 1/desiredFPS
TE_pntr = 0 ' no events in stack
Loops = 0 : Frames = 0
ScreenSet 1, 0 ' working page #1, visible page #0
DrawGrid
PQ_TE_Add(timer+RefreshTime,100) ' add the next screen refresh to Timer Event Stack (100 = refresh screen event)
' Main Loop
do
Loops = Loops + 1
if timer > PQ_TE(TE_pntr,0) then 'check timer against the next event time
select case PQ_TE(TE_pntr,1) ' figure out what Event needs to be dealt with
case 100 ' this is the code for RefreshScreen Event
Refreshscreen
case 200 ' could be an action or world update or even animation frame change...
end select
end if
loop until inkey = "q"
end
' some subroutines....
sub Refreshscreen
dim as double t1
t1 = timer
'PQ_TE_Del(TE_pntr) ' remove the Event
TE_pntr -= 1 ' Quick n Dirty remove this event
PQ_TE_Add(t1+RefreshTime,100) ' add a new Scren Refresh Event to Timer Event Stack
' FPS stuff
FPS = 1/(t1 - OldTime) ' time between frames
OldTime = t1 'reset OldTime
locate 3,70 : print "Main Loops per Frame =";Loops;" "
locate 5,70 : print "Display FPS =";FPS;" "
locate 7,70 : print "Timer =";t1;" "
locate 9,70 : print "Refresh Time = ";RefreshTime
ScreenCopy
Loops = 0 'reset Loop counter
end sub
sub DrawGrid
dim as integer x1, y1
dim as ulong c1
cls
' draw grid
for i as integer = 1 to 100
x1 = i*TILEW
for j as integer = 1 to 100
y1 = j*TILEH
c1 = rgb(200,200,200)
select case map(i,j,0)
case 1
c1 = rgb(0,255,0)
case 2
c1 = rgb(255,0,0)
case 3
c1 = rgb(0,0,255)
case 4
c1 = rgb(255,255,0)
end select
line(x1,y1)- step(TILEW-2,TILEH-2),c1,BF
next j
next i
end sub
'
' this is a Sorted Array which maintains an array in sorted order
'
'
function PQ_TE_Add(ByVal newtime as double, byval event as double) as integer
' Adds an event to the Timer Event Stack Sorted Array
' this function uses and alters the shared variables: PQ_TE() & TE_pntr
' ... add it to the end then bubble sort it down...
dim as integer bub, addHere
TE_pntr = TE_pntr + 1
addHere = TE_pntr
PQ_TE(TE_pntr,0) = newtime
PQ_TE(TE_pntr,1) = event
if TE_pntr > 1 then
bub = TE_pntr
do
if PQ_TE(bub,0) > PQ_TE(bub-1,0) then
swap PQ_TE(bub,0) , PQ_TE(bub-1,0)
swap PQ_TE(bub,1) , PQ_TE(bub-1,1)
addHere = bub - 1
else
bub = 2 ' early exit
end if
bub = bub - 1
loop until bub < 2
end if
return addHere
end function
function PQ_TE_Del(ByVal thisOne as integer) as integer
' Deletes an event from the Timer Event Stack Sorted Array
select case thisOne
case is < TE_pntr
for i as integer = thisOne to (TE_pntr-1)
PQ_TE(i,0) = PQ_TE(i+1,0)
PQ_TE(i,1) = PQ_TE(i+1,1)
next i
TE_pntr = TE_pntr - 1
case is = TE_pntr
TE_pntr = TE_pntr - 1
end select
return thisOne
end function(1) Is this a good way to structure my program timings?
(2) What are the possible issues that this sort of structure might have? I assume it will easily keep track of Sprite Frame changes in addition to any other time-based event updates.
(3) Will the overhead required in 'unpacking' the event info end up becoming a mess? For instance, an Sprite Frame Change event would have to include some additional info like the Sprite # which would need to be stored with the TImer Event (PQ_TE(1000,2) in the above example, not used)
What other methods besides this one should I consider to accomplish my goals (keeping track of the timing for everything requiring it, and of course, overall program speed)