Drawing Circles

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Socoder -> Blitz -> Drawing Circles
Wed, 04 Oct 2006, 04:05
mike_g	I'm trying to make a line of sight function for my game, but I am not very good at maths. If you run this demo you can see a function that draws on a grid from the player to the distance he can see. It has a diamond shape that dont look right so now I want a circle. I found the formula for a circle but kinda made a mess of what I was trying to do. You can see my mess by commenting out LOS and un-commenting LOS2. Anyway can someone please show me, in stupid peoples terms, how I can create a circle. ;LINE OF SIGHT Graphics 1024, 768 SetBuffer BackBuffer() Dim cells(48, 48) Dim sight(48, 48) Global player_x=20, player_y=20, sight_range=15 While Not KeyHit(1) LOS(player_x, player_y, sight_range) ;LOS2(player_x, player_y, 30) DRAW_ALL() MOVE() Flip Wend Function LOS(x, y, range) For y = player_y - range -1 To player_y + range+1 If y > 47 Then Exit While y < 0: y=y+1 :Wend For x = player_x - range-1 To player_x + range+1 If x > 47 Then Exit While x < 0: x=x+1 :Wend x_diff = Abs(player_x - x) y_diff = Abs(player_y - y) If (x_diff + y_diff) <= range sight(x, y) = 1 Else sight(x, y) = 0 EndIf Next Next End Function Function LOS2(x#, y#, range) For y# = 0 To 25 x_pos# = Sqr((xx)+(yy)) x_pos# = Floor(x_pos#+0.5) sight(x_pos#, y) = 1 Next End Function ;---------------------------------; ;***** STUFF FOR DEMO *******; ;---------------------------------; Function DRAW_ALL() Color 50, 100, 50: Rect 0, 0, 1024, 768 Color 100, 50, 50 For y = 0 To 47 For x = 0 To 47 If sight(x, y) = 1 Then Rect x16, y16, 16, 16 If x = player_x And y = player_y Color 100, 100, 100: Rect player_x16, player_y*16, 16, 16: Color 100, 50, 50 EndIf Next Next End Function ;---------------------------------; Function MOVE() If KeyHit(200) player_y = player_y - 1 Else If KeyHit(203) player_x = player_x - 1 Else If KeyHit(205) player_x = player_x + 1 Else If KeyHit(208) player_y = player_y + 1 EndIf End Function ;---------------------------------; --v
Wed, 04 Oct 2006, 04:34
Jayenkai	;LINE OF SIGHT Graphics 1024, 768,32 ,2 SetBuffer BackBuffer() Dim cells(48, 48) Dim sight(48, 48) Global player_x=20, player_y=20, sight_range=15 While Not KeyHit(1) LOS(player_x, player_y, sight_range) ;LOS2(player_x, player_y, 30) DRAW_ALL() MOVE() Flip Wend Function LOS(x, y, range) For ang=0 To 360 Step 5 For sightlength=0 To range+5 sight(x+(Sin(ang)sightlength), y-(Cos(ang)sightlength) ) =1 If sightlength>range Then sight(x+(Sin(ang)sightlength), y-(Cos(ang)sightlength) ) =0 Next Next End Function Function LOS2(x#, y#, range) For y# = 0 To 25 x_pos# = Sqr((xx)+(yy)) x_pos# = Floor(x_pos#+0.5) sight(x_pos#, y) = 1 Next End Function ;---------------------------------; ;***** STUFF FOR DEMO *******; ;---------------------------------; Function DRAW_ALL() Color 50, 100, 50: Rect 0, 0, 1024, 768 Color 100, 50, 50 For y = 0 To 47 For x = 0 To 47 If sight(x, y) = 1 Then Rect x16, y16, 16, 16 If x = player_x And y = player_y Color 100, 100, 100: Rect player_x16, player_y16, 16, 16: Color 100, 50, 50 EndIf Next Next End Function ;---------------------------------; Function MOVE() If KeyHit(200) player_y = player_y - 1 Else If KeyHit(203) player_x = player_x - 1 Else If KeyHit(205) player_x = player_x + 1 Else If KeyHit(208) player_y = player_y + 1 EndIf End Function ;---------------------------------; --v Circle = CenterX+(Sin(Angle)Distance), CenterY-(Cos(Angle)*Distance) Oh, and if you tweak the "Step 5", you get a "Blindspot" type effect.. -=-=- ''Load, Next List!''
Wed, 04 Oct 2006, 06:46
mike_g	Thanks Jay Diablosdevil posted a different version on Dev Crunch, you both seem to be using trigonomery, so i guess it must a better way to do this. I'll check em both out when I get home and figure out how they work.