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Forum Index : Microcontroller and PC projects : sprite collision simplify please

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stanleyella

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Joined: 25/06/2022
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Posted: 09:05pm 05 Nov 2024
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matherp
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Posted: 10:30pm 05 Nov 2024
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NO
 
LeoNicolas

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Posted: 04:48pm 06 Nov 2024
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In my game Knightmare, I followed the instructions from the CMM2 Basic manual, and it worked very well.

This is my implementation for my game:

https://github.com/leonicolas/knightmare-cmm2/blob/main/collision.inc
 
stanleyella

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Posted: 04:49pm 06 Nov 2024
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sorry, I'm looking at appendix sprite collision.
I got 16 sprites, each can be sprite 1 or sprite 2, for animation and I can do 4 tests to see if any of the 16 sprites overlap the cannon or hit by missile.
I just thought the sprite collision testing 16 sprites would be faster.
probably is. more study needed.
 
thwill

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Joined: 16/09/2019
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Posted: 05:01pm 06 Nov 2024
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Note that (I believe) one of the (several?) wrinkles with the SPRITE function is that if you use SPRITE(C, #1) to get the number of collisions for sprite #1 and then iterate through and handle them using SPRITE(C, #1, m) then things can get "fun" if in handling the collisions you actually change the number of collisions, e.g. by destroying/hiding a sprite representing a bullet that has just collided ... you can end up missing a collision or trying to handle an invalid sprite #0. I believe this issue hits Knightmare currently requiring an ON ERROR to avoid the bad result.

Best wishes,

Tom
Edited 2024-11-07 03:16 by thwill
Game*Mite, CMM2 Welcome Tape, Creaky old text adventures
 
stanleyella

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Posted: 05:32pm 06 Nov 2024
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it's all for n=1 to sprites active
test each of 3 missiles collided with any sprite, explode ,missile inactive ,sprite inactive.

if sprite1x+sprite1_width < sprite2x then
if sprite1x>sprite2x+sprite2_width then
if sprite1y+sprite1_height < sprite2y then
if sprite1y>sprite2y+sprite2_height then end if
else collided
 
LeoNicolas

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Posted: 06:05pm 06 Nov 2024
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  thwill said  Note that (I believe) one of the (several?) wrinkles with the SPRITE function is that if you use SPRITE(C, #1) to get the number of collisions for sprite #1 and then iterate through and handle them using SPRITE(C, #1, m) then things can get "fun" if in handling the collisions you actually change the number of collisions, e.g. by destroying/hiding a sprite representing a bullet that has just collided ... you can end up missing a collision or trying to handle an invalid sprite #0. I believe this issue hits Knightmare currently requiring an ON ERROR to avoid the bad result.

Best wishes,

Tom


Yes, you are right. I'm using on error skip because is easier and faster to avoid the edge cases than creating a more complex logic to skip the invalid cases.
 
stanleyella

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Posted: 10:24pm 06 Nov 2024
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converting gcbasic to mmbasic
https://www.youtube.com/watch?v=9pys3Y8_bns
 
Mixtel90

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Posted: 10:50pm 06 Nov 2024
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But *why* Stan? Just use the one that's best for the job. :)
Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs
 
stanleyella

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Posted: 11:57pm 06 Nov 2024
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gcbasic never supported ili9341 and the arduino demo is a long story to implement but the logic is valid in mmbasic and uses frame f so it's just an exercise to learn mmbasic. world of difference between gcb and mmb
 
Volhout
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Posted: 08:31am 07 Nov 2024
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Stan,

In "Rocks" I simply check sprite coordinates in MMBasic. When there are not many, it s doable and mantain a decent number fo frames per second
The same is also used in PETSCII robots (there some sprites are in a different framebuffer).

When there are many sprites, and checking intersprite collisions, then it slows down the game. But you can (as in PETSCII) only check Y coordinate, and when that is close, evaluate X coordinate.

Volhout
Edited 2024-11-07 18:32 by Volhout
PicomiteVGA PETSCII ROBOTS
 
stanleyella

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Posted: 10:14pm 07 Nov 2024
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Rocks is interesting code.
I thought again about "Missile Command" now mouse demo read x,y worked and guess scroll wheel click button is detected so want to try coding and rocks missile routines could be useful as can't find my line x,y,x2,y2 pixel at a time code, Bresenham's line algorithm
the original game video https://www.google.com/search?client=opera&q=missile+command+video+game&sourceid=opera&ie=UTF-8&oe=UTF-8#fpstate=ive&vld=cid:3f819b2c,vid:tz4YCQaOxOI,st:0
Edited 2024-11-08 08:35 by stanleyella
 
stanleyella

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Posted: 10:44pm 07 Nov 2024
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found this
plotLine(x0, y0, x1, y1)
   if abs(y1 - y0) < abs(x1 - x0)
       if x0 > x1
           plotLineLow(x1, y1, x0, y0)
       else
           plotLineLow(x0, y0, x1, y1)
       end if
   else
       if y0 > y1
           plotLineHigh(x1, y1, x0, y0)
       else
           plotLineHigh(x0, y0, x1, y1)
       end if
   end if
 
stanleyella

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Posted: 12:45am 08 Nov 2024
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this is the line command using plot.
now mmbasic I'll get it to do 1 pixel each call. I'll edit the for nexts and use the values , hope
Bresenham's line algorithm, it's fast on 2350 hdmi ,just academic , line is obviously faster but interesting it works so fast. hdmi usb, faster vga higher cpuspeed. 
cls
x0=10:y0=10:x1=100:y1=150
plotLine(x0, y0, x1, y1)
x0=120:y0=120:x1=160:y1=60
plotLine(x0, y0, x1, y1)
x0=150:y0=70:x1=50:y1=100
plotLine(x0, y0, x1, y1)
x0=40:y0=120:x1=170:y1=6
plotLine(x0, y0, x1, y1)
end
sub plotLine(x0, y0, x1, y1)
   if abs(y1 - y0) < abs(x1 - x0) then
       if x0 > x1 then
           plotLineLow(x1, y1, x0, y0)
       else
           plotLineLow(x0, y0, x1, y1)
       end if
   else
       if y0 > y1 then
           plotLineHigh(x1, y1, x0, y0)
       else
           plotLineHigh(x0, y0, x1, y1)
       end if
   end if
end sub
'
sub plotLineHigh(x0, y0, x1, y1)
   dx = x1 - x0
   dy = y1 - y0
   xi = 1
   if dx < 0 then
       xi = -1
       dx = -dx
   end if
   D = (2 * dx) - dy
   x = x0

   for y = y0 to y1
       pixel x, y
       if D > 0 then
           x = x + xi
           D = D + (2 * (dx - dy))
       else
           D = D + 2*dx
       end if
   next
end sub
'
sub plotLineLow(x0, y0, x1, y1)
   dx = x1 - x0
   dy = y1 - y0
   yi = 1
   if dy < 0 then
       yi = -1
       dy = -dy
   end if
   D = (2 * dy) - dx
   y = y0

   for x = x0 to x1
       pixel x, y
       if D > 0 then
           y = y + yi
           D = D + (2 * (dy - dx))
       else
           D = D + 2*dy
       end if
   next
end sub
Edited 2024-11-08 11:21 by stanleyella
 
stanleyella

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Posted: 01:34am 08 Nov 2024
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this was when I used picaxe basic and I got oled 1306 to work and implement line cos it  wasn't supported. had to work out the 1k buffer. 7 years ago. I moved to gcbasic, then mmbasic, where you don't have to do graphics, they're all sorted
https://www.youtube.com/watch?v=kL3c1wry9ok
picaxe was ok but slow and variables???
gcbasic pissed all over it but 8 bit, best was logic green technology 328 which ran at 32mhz, twice as fast as arduino 328 but mmbasic pissed all over gcbasic. I'm not very loyal am I?
Edited 2024-11-08 11:59 by stanleyella
 
Martin H.

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Joined: 04/06/2022
Location: Germany
Posts: 1113
Posted: 08:18am 08 Nov 2024
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With "Gems N Rocks", for example, I made it so that the sprites were permanently queried and moved from bottom to top... always several rows per pass.
The position of the stones and other objects on the playing field were managed in a 2-dimensional array. All movements and collision queries only took place in the array.
On the screen, only the contents of the array were displayed  but no collision detection were made there..
the advantage is that objects are also moved that are outside the screen and are therefore not currently displayed
Edited 2024-11-08 22:15 by Martin H.
'no comment
 
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