2. Main Program (Looping)
Draw the plane
Define keys : Esc to quit, Left and Right to move the plane
Draw enemies
Bullet is auto shoot
Still have miss lots of features ... somebody please add some code to detect collision between a bullet and an enemy, I am running out of idea on how to code collision detect
'MAIN PROGRAM
do
'SET BACKGROUND
cls
draw image 4,0,0
'THE PLANE
draw image 1,planeX,planeY
'ESC TO QUIT, LEFT AND RIGHT KEYS TO MOVE THE PLANE
if keydown(KEY_ESCAPE) then end
if keydown(KEY_LEFT) then planeX=planeX-speed
if keydown(KEY_RIGHT) then planeX=planeX+speed
'ENEMIES
for x=0 to 2
if enemyY[x]>480 then
enemyX[x]=rnd(640)
enemyY[x]=-rnd(50)
else
enemyY[x]=enemyY[x]+speed
endif
next
for x=0 to 2
draw image 3,enemyX[x],enemyY[x]
next
'BULLET, AUTO SHOOT
if bulletY < 480 then
bulletY = bulletY - speed*3
endif
if bulletY = 100 then
bulletX = planeX+15
bulletY = planeY
endif
2. Main Program (Looping)
Draw the plane
Define keys : Esc to quit, Left and Right to move the plane
Draw enemies
Bullet is auto shoot
Still have miss lots of features ... somebody please add some code to detect collision between a bullet and an enemy, I am running out of idea on how to code collision detect
'MAIN PROGRAM
do
'SET BACKGROUND
cls
draw image 4,0,0
'THE PLANE
draw image 1,planeX,planeY
'ESC TO QUIT, LEFT AND RIGHT KEYS TO MOVE THE PLANE
if keydown(KEY_ESCAPE) then end
if keydown(KEY_LEFT) then planeX=planeX-speed
if keydown(KEY_RIGHT) then planeX=planeX+speed
'ENEMIES
for x=0 to 2
if enemyY[x]>480 then
enemyX[x]=rnd(640)
enemyY[x]=-rnd(50)
else
enemyY[x]=enemyY[x]+speed
endif
next
for x=0 to 2
draw image 3,enemyX[x],enemyY[x]
next
'BULLET, AUTO SHOOT
if bulletY < 480 then
bulletY = bulletY - speed*3
endif
if bulletY = 100 then
bulletX = planeX+15
bulletY = planeY
endif
draw image 2,bulletX,bulletY
'WAIT BEFORE LOOPING
wait 40
loop
Looking good!
But may I suggest that you add 'set redraw off' on the line after 'set window' and 'redraw' before 'wait 40'?
Naalaa has a hidden image (a back buffer) the same size as the window. When you draw something (an image, a line of text or anything) it is drawn on the hidden image. If you haven't called 'set redraw off', every time you draw something the entire hidden image is copied to the window. If you have called 'set redraw off', the hidden image is only copied to the window when you manually call 'redraw'. This is much faster and removes "flickering" graphics.
Regarding collision, "just" check if two images overlap. It's easier to understand if you draw some on a paper
Code:
for x=0 to 2
dead = bulletX + width(2) > enemyX[x] and bulletX < enemyX[x] + width(3) and
bulletY + height(2) > enemyY[x] and bulletY < enemyY[x] + height(3)
if enemyY[x]>480 or dead then
enemyX[x]=rnd(640)
enemyY[x]=-rnd(50)
else
enemyY[x]=enemyY[x]+speed
endif
next
Oh man. This game brings back memories... 1945. Classic.
If memory serves correctly, I may have the Naalaa5 version, floating around on a drive somewhere. If I can find it, you can use it for reference or even convert it to Naalaa7... Either way I will look forward to playing your game. Classic.
'MAIN PROGRAM
do
'SET BACKGROUND
cls
draw image 4,0,0
'THE PLANE
draw image 1,planeX,planeY
'ESC TO QUIT, LEFT AND RIGHT KEYS TO MOVE THE PLANE
if keydown(KEY_ESCAPE) then end
if keydown(KEY_LEFT) then planeX=planeX-speed
if keydown(KEY_RIGHT) then planeX=planeX+speed
'ENEMIES
for x=0 to 2
'collision detection if bullet and enemy image overlap
dead = bulletX + width(2) > enemyX[x] and bulletX < enemyX[x] + width(3) and
bulletY + height(2) > enemyY[x] and bulletY < enemyY[x] + height(3)
if enemyY[x]>480 or dead then
enemyX[x]=rnd(640)
enemyY[x]=-rnd(50)
else
enemyY[x]=enemyY[x]+speed
endif
next
for x=0 to 2
draw image 3,enemyX[x],enemyY[x]
next
'BULLET, AUTO SHOOT
if bulletY < 480 then
bulletY = bulletY - speed*3
endif
if bulletY = 100 then
bulletX = planeX+15
bulletY = planeY
endif
'MAIN PROGRAM
do
'SET BACKGROUND
cls
draw image 4,0,0
'THE PLANE
draw image 1,planeX,planeY
'ESC TO QUIT, LEFT AND RIGHT KEYS TO MOVE THE PLANE
if keydown(KEY_ESCAPE) then end
if keydown(KEY_LEFT) then planeX=planeX-speed
if keydown(KEY_RIGHT) then planeX=planeX+speed
'ENEMIES
for x=0 to 2
'collision detection if bullet and enemy image overlap
dead = bulletX + width(2) > enemyX[x] and bulletX < enemyX[x] + width(3) and
bulletY + height(2) > enemyY[x] and bulletY < enemyY[x] + height(3)
if enemyY[x]>480 or dead then
enemyX[x]=rnd(640)
enemyY[x]=-rnd(50)
else
enemyY[x]=enemyY[x]+speed
endif
next
for x=0 to 2
draw image 3,enemyX[x],enemyY[x]
next
'BULLET, AUTO SHOOT
if bulletY < 480 then
bulletY = bulletY - speed*3
endif
if bulletY = 100 then
bulletX = planeX+15
bulletY = planeY
endif
No problems! I've added two more versions of your program, but you can ignore them for now if they seem confusing
In 1945_2.n7 I've replaced your two arrays, enemyX and enemyY, with a 2D array, so that the x value of enemy n is in enemy[n][0] and the y value is in enemy[n][1].
1945_3.n7 is a modification of 1945_2.n7, but instead of using enemy[n][0] and enemy[n][1] for position, I use enemy[n].x and enemy[n].y, which makes it easier to read the code.
The . (dot) notation, as in enemy[n].x, really isn't a complicated thing. In n7 you can use both numbers and strings as "keys" to tables. An array is what I call a table where only numeric keys (indexes) are used.
(11-29-2023, 06:01 PM)Marcus Wrote: ...
The . (dot) notation, as in enemy[n].x, really isn't a complicated thing. In n7 you can use both numbers and strings as "keys" to tables. An array is what I call a table where only numeric keys (indexes) are used.
...
Thank you for sharing the .(dot) notation ... It improves the readibility of the source code...
I tried to use it and it worked well
I love NAALAA
... somebody please add some code to detect collision between a bullet and an enemy, I am running out of idea on how to code collision detect 
