millfork/examples/x16/balls.mfk

// the emulator supports only 16 sprites:
const byte SPRITE_COUNT = 16
array(vera_sprite_data) sprites[SPRITE_COUNT]
array(sbyte) vx[SPRITE_COUNT]
array(sbyte) vy[SPRITE_COUNT]

import random

void main () {
    pointer.vera_sprite_data p

    byte i,j
    word x,y
    init_rand_seed()
    // make balls striped
    for i,0,parallelto,$1f {
        for j,1,parallelto,$f {
            sprite_bitmap[nonet(j<<5) + i] *= j
        }
    }
    for i,0,paralleluntil,SPRITE_COUNT {
        p = sprites[i].pointer
        // bitmap is at $10000:
        p->address = $800
        p->x.lo = rand()
        p->x.hi = rand() & 1
        p->y = rand()
        // no collision, above all layers, no flipping
        p->ctrl0 = $c
        // 32×32 pixels, different palette offsets
        p->ctrl1 = $a0 | (i & $f)
        vx[i] = 1 - (rand() & 2)
        vy[i] = 1 - (rand() & 2)
    }
    vera_upload_large($10000, sprite_bitmap.addr, sizeof(sprite_bitmap))
    vera_upload_large(VERA_SPRITES, sprites.addr, sizeof(sprites))
    // enable sprites:
    vera_poke(VERA_SPRITE_CTRL, 1)
    while true {
        for i,0,paralleluntil,SPRITE_COUNT {
            p = sprites[i].pointer
            x = p->x
            y = p->y
            x += vx[i]
            y += vy[i]
            p->x = x
            p->y = y
            if x == 0 { vx[i] = 1 }
            if x >= 640-32 { vx[i] = 0-1 }
            if y == 0 { vy[i] = 1 }
            if y >= 480-32 { vy[i] = 0-1 }
        }
        vera_upload_large(VERA_SPRITES, sprites.addr, sizeof(sprites))
    }
}


array sprite_bitmap = [
$00,$00,$00,$00,$00,$00,$11,$11,$11,$11,$00,$00,$00,$00,$00,$00,
$00,$00,$00,$00,$01,$11,$11,$11,$11,$11,$11,$10,$00,$00,$00,$00,
$00,$00,$00,$01,$11,$11,$11,$11,$11,$11,$11,$11,$10,$00,$00,$00,
$00,$00,$00,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$00,$00,$00,
$00,$00,$01,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$10,$00,$00,
$00,$00,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$00,$00,
$00,$01,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$10,$00,
$00,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$00,
$00,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$00,
$01,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$10,
$01,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$10,
$01,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$10,
$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,
$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,
$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,
$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,
$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,
$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,
$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,
$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,
$01,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$10,
$01,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$10,
$01,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$10,
$00,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$00,
$00,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$00,
$00,$01,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$10,$00,
$00,$00,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$00,$00,
$00,$00,$01,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$10,$00,$00,
$00,$00,$00,$11,$11,$11,$11,$11,$11,$11,$11,$11,$11,$00,$00,$00,
$00,$00,$00,$01,$11,$11,$11,$11,$11,$11,$11,$11,$10,$00,$00,$00,
$00,$00,$00,$00,$01,$11,$11,$11,$11,$11,$11,$10,$00,$00,$00,$00,
$00,$00,$00,$00,$00,$00,$11,$11,$11,$11,$00,$00,$00,$00,$00,$00
]