Wiki help: https://qb64phoenix.com/qb64wiki/index.php/HYPOT
What wiki doesn't say is that this function contains a very useful Distance Formula between two points on a 2D plane.
Distance between two points (x1, y1) and (x2, y2) ( a diagram would be helpful here, sorry I am going to attempt in words only).
Distance = SQR((x1 - x2) ^ 2 + (y1 - y2) ^ 2)
(x1 - x2) represents the length of one leg of a right triangle
(y1 - y2) represents the other leg
So by the Pythagorean Theorem the Hypotenuse (length) equals the SQR of the square (^2) of both sides.
ie Distance = _Hypot(x1 - x2), (y1 - y2))
The point is we have a Distance formula built-into the QB64 Functions and don't need to carry a Distance Function from our Toolbox of Subs and Functions.
I bring this up because I am kicking myself for missing it yesterday in the enRitchied Code for Missile Command here:
https://qb64phoenix.com/forum/showthread...8#pid17088
I shoulda, coulda, done it better like this:
Update: testing what happens when I edit this post and save.
Update again: lost the nice edge on right side, can I get it back? No I guess not.
What wiki doesn't say is that this function contains a very useful Distance Formula between two points on a 2D plane.
Distance between two points (x1, y1) and (x2, y2) ( a diagram would be helpful here, sorry I am going to attempt in words only).
Distance = SQR((x1 - x2) ^ 2 + (y1 - y2) ^ 2)
(x1 - x2) represents the length of one leg of a right triangle
(y1 - y2) represents the other leg
So by the Pythagorean Theorem the Hypotenuse (length) equals the SQR of the square (^2) of both sides.
ie Distance = _Hypot(x1 - x2), (y1 - y2))
The point is we have a Distance formula built-into the QB64 Functions and don't need to carry a Distance Function from our Toolbox of Subs and Functions.
I bring this up because I am kicking myself for missing it yesterday in the enRitchied Code for Missile Command here:
https://qb64phoenix.com/forum/showthread...8#pid17088
I shoulda, coulda, done it better like this:
Code: (Select All)
Option _Explicit ' Get into this habit and save yourself grief from Typos
_Title "Missile Command EnRitchied" ' another b+ mod 2023-06-24, replace distance with _Hypot.
' I probably picked up this game at the JB forum some years ago.
' Get Constants, Shared Variables and Arrays() declared. These Will Start with Capital Letters.
' Get Main module variables and arrays declared with starting lower case letters for local.
' This is what Option _Explicit helps, by forcing us to at least declare these before use.
' While declaring, telling QB64 the Type we want to use, we can also give brief description.
Const ScreenWidth = 800, ScreenHeight = 600 ' for our custom screen dimensions
Dim As Integer bombX, bombY ' incoming bomb screen position to shoot down
Dim As Single bombDX, bombDY ' DX and DY mean change in X position and Y position
Dim As Integer missileX, missileY ' missile position
Dim As Single missileDX, missileDY ' change X and Y of Missile position
Dim As Integer hits, misses ' score hits and misses
Dim As Integer mouseDistanceX, mouseDistanceY ' for calculations of missile DX, DY direction
Dim As Single distance ' ditto
Dim As Integer radius ' drawing hits with target like circles
Dim As Integer boolean ' to shorten the code line with a bunch of OR tests
Screen _NewImage(ScreenWidth, ScreenHeight, 32) ' sets up a graphics screen with custom dimensions
' the 32 is for _RGB32(red, green, blue, alpha) coloring.
'
_ScreenMove 250, 60 ' this centers screen in my laptop, you may need different numbers
InitializeForRound: ' reset game and start a round with a bomb falling
Cls
bombX = Rnd * ScreenWidth ' starts bomb somewhere across the screen
bombY = 0 ' starts bomb at top of screen
bombDX = Rnd * 6 - 3 ' pick rnd dx = change in x between -3 and 3
bombDY = Rnd * 3 + 3 ' pick rnd dy = change in y between 3 and 6, > 0 for falling
missileX = ScreenWidth / 2 ' missile base at middle across screen
missileY = ScreenHeight - 4 ' missile launch point at missile base is nearly at bottom of screen
missileDX = 0 ' missile is not moving awaiting mouse click for direction
missileDY = 0 ' ditto
distance = 0 ' distance of mouse click to missile base
Do
'what's the score?
_Title "Click mouse to intersect incoming Hits:" + Str$(hits) + ", misses:" + Str$(misses)
_PrintString (400, 594), "^" ' draw missle base = launch point
While _MouseInput: Wend ' poll mouse to get update
If _MouseButton(1) Then ' the mouse was clicked calc the angle from missile base
mouseDistanceX = _MouseX - missileX
mouseDistanceY = _MouseY - missileY
distance = (mouseDistanceX ^ 2 + mouseDistanceY ^ 2) ^ .5
missileDX = 5 * mouseDistanceX / distance
missileDY = 5 * mouseDistanceY / distance
End If
missileX = missileX + missileDX ' update missile position
missileY = missileY + missileDY ' ditto
bombX = bombX + bombDX ' update bomb position
bombY = bombY + bombDY ' ditto
' I am about to use a boolean variable to shorten a very long IF code line
' boolean is either 0 or -1 when next 2 statements are execued
' -1/0 or True/False is everything still in screen?
boolean = missileX < 0 Or missileY < 0 Or bombX < 0 Or bombY < 0
boolean = boolean Or missileX > ScreenWidth Or bombX > ScreenWidth Or bombY > ScreenHeight
If boolean Then ' done with this boolean
' reuse boolean to shorten another long code line checking if bomb and missile in screen
boolean = bombY > ScreenHeight Or missileX < 0 Or missileY < 0 Or missileX > ScreenWidth
If boolean Then misses = misses + 1
GoTo InitializeForRound
End If
' if the distance between missle and bomb < 20 pixels then the missile got the bomb, a hit
'If ((missileX - bombX) ^ 2 + (missileY - bombY) ^ 2) ^ .5 < 20 Then ' show a strike as target
'rewrite the above line using _Hypot() which is hidden distance forumla
If _Hypot(missileX - bombX, missileY - bombY) < 20 Then
For radius = 1 To 20 Step 4 ' draw concetric circles to show strike
Circle ((missileX + bombX) / 2, (missileY + bombY) / 2), radius
_Limit 60
Next
hits = hits + 1 ' add hit to hits score
GoTo InitializeForRound
Else
PSet (missileX, missileY), &HFFFFFF00 ' draw your missle yellow
PSet (bombX, bombY), &HFF0000FF ' draw bomb blue
End If
_Limit 20
Loop
Update: testing what happens when I edit this post and save.
Update again: lost the nice edge on right side, can I get it back? No I guess not.
b = b + ...
