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   Bernie (codewiz@mstdn.io)'s status on Friday, 29-Mar-2024 23:58:17 JST Bernie

   in reply to

   Now you could write FOR loops to change the X and Y coordinates of your sprite and smoothly animate it on the screen.

   I tried this when I was 8 or 9 years old, and since then I've been hooked to coding 🤓

   • Linux Walt Alt (@lnxw37a2) {3EB165E0-5BB1-45D2-9E7D-93B31821F864} likes this.
   • Embed this notice
     Bernie (codewiz@mstdn.io)'s status on Friday, 29-Mar-2024 23:58:18 JST Bernie

     in reply to

     If you wanted to use more interesting artwork for your sprites, you'd have to convert a 24x21 bitmap data to its binary representation, then load it into memory.

     The original Commodore 64 User Manual had a nice sample program to do this on pages 70 and 71:
     https://www.commodore.ca/manuals/c64_users_guide/c64-users_guide-06-sprite_graphics.pdf

     #c64 #programming #retrocomputing

   • Embed this notice
     Bernie (codewiz@mstdn.io)'s status on Friday, 29-Mar-2024 23:58:19 JST Bernie

     in reply to

     If you want to display something other than garbage, you need to move the sprite pointer to a free memory area and then write some bitmap data to it.

     Let's use address 12800 ($3200 in hex). That's 200 * 64:

     poke 2048,200

     Now let's fill this area with some data:

     10 p=12800
     20 for i = 0 to 62
     30 poke p+i,i+1
     40 next

     You should see the typical fractalish pattern of a binary sequence.

     The pattern repeats 3 times horizontally because each line is 24 pixels wide (3 bytes).

     #c64 #retrocomputing

   • Embed this notice
     Bernie (codewiz@mstdn.io)'s status on Friday, 29-Mar-2024 23:58:22 JST Bernie

     in reply to

     This will change sprite 0 color to yellow:

     poke 53287,7

     There are 16 colors from 0 to 15. Sprites can also be displayed in multicolor mode (4 colors), but currently we're in high-res mode.

     #c64

   • Embed this notice
     Bernie (codewiz@mstdn.io)'s status on Friday, 29-Mar-2024 23:58:22 JST Bernie

     in reply to

     This will stretch sprite 0 vertically, doubling its height:

     poke 53271,1

     ...and this will stretch it horizontally:

     poke 53277,1

     #c64

   • Embed this notice
     Bernie (codewiz@mstdn.io)'s status on Friday, 29-Mar-2024 23:58:22 JST Bernie

     in reply to

     So far, we did not change the sprite pointers, so we're viewing raw memory, specifically addresses 0 to 63.

     Page 0 holds various system variables, so the sprite will flicker as interrupts and basic routines write to it.

     This will move the sprite 0 data pointer to the address range 64-127 ($40-$7F):

     poke 2040,1

     Blocks 2 ($80-BF) and 3 ($C0-FF) contain more interesting stuff: timer counters and variables that change when you move around the cursor.

     #c64 #retrocomputing

   • Embed this notice
     Bernie (codewiz@mstdn.io)'s status on Friday, 29-Mar-2024 23:58:23 JST Bernie

     The #C64 has 8 hardware sprites. You can play with them with a few POKEs:

     rem turn on all 8 sprites
     poke 53269,255

     rem set sprite 0 x and y pos
     poke 53248,50
     poke 53249,60

     (lowercase so you can directly paste into VICE)

     #retrocomputing #programming