initial commit

2026-07-18 18:34:28 +02:00
commit e9c69864f1
18 changed files with 2472 additions and 0 deletions
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+; -----------------------------------------------------------
+; intro.asm - boot screen ported from rabbitc64: giant TTG
+; letters built from 8x8 bitmaps with a gold color wash
+; running down them, TELETYPE GAMES / PRESENTS below;
+; advances to the menu after a few seconds or on fire
+; -----------------------------------------------------------
+
+INTRO_LROW = 3           ; top cell row of the giant letters
+INTRO_TIME = 250         ; frames before it advances on its own
+
+intro_init:
+    jsr clear_screen
+
+    ; T T G at columns 6 / 16 / 26
+    lda #<glyph_t
+    sta txtlo
+    lda #>glyph_t
+    sta txthi
+    lda #6
+    sta g8col
+    jsr draw_glyph8
+    lda #16
+    sta g8col
+    jsr draw_glyph8
+    lda #<glyph_g
+    sta txtlo
+    lda #>glyph_g
+    sta txthi
+    lda #26
+    sta g8col
+    jsr draw_glyph8
+
+    +prtext 13, 13, WHITE, txt_ttgname, 14
+    +prtext 15, 16, LGREY, txt_presents, 8
+
+    lda #INTRO_TIME
+    sta introt
+    lda #0
+    sta washphase
+    +setupd intro_update
+    rts
+
+intro_update:
+    ; gold wash: recolor the letter rows from the cyclic ramp
+    inc washphase
+    lda #0
+    sta g8row
+iw_row:
+    lda #INTRO_LROW
+    clc
+    adc g8row
+    tax
+    jsr row_ptr
+    lda washphase
+    lsr                  ; half speed keeps the shimmer gentle
+    clc
+    adc g8row
+    and #15
+    tax
+    lda washtbl,x
+    sta rtmp
+    ldy #33              ; the letters span columns 6-33
+iw_col:
+    lda (scrlo),y
+    cmp #$a0             ; only touch the letter blocks
+    bne iw_skip
+    lda rtmp
+    sta (collo),y
+iw_skip:
+    dey
+    cpy #5
+    bne iw_col
+    inc g8row
+    lda g8row
+    cmp #8
+    bne iw_row
+
+    ; fire skips, otherwise wait out the timer
+    jsr start_edge
+    beq iw_tick
+    jmp menu_init
+iw_tick:
+    dec introt
+    bne iw_done
+    jmp menu_init
+iw_done:
+    rts
+
+; ---- draw an 8x8-cell giant letter: txtlo/hi = 8-byte
+; bitmap, g8col = left cell column ----
+draw_glyph8:
+    lda #0
+    sta g8row
+g8_row:
+    lda #INTRO_LROW
+    clc
+    adc g8row
+    tax
+    jsr row_ptr
+    ldy g8row
+    lda (txtlo),y
+    sta curbits
+    ldy g8col
+    lda #8
+    sta bitcnt
+g8_bit:
+    asl curbits          ; leftmost pixel first
+    bcc g8_next
+    lda #$a0             ; inverse space = solid block
+    sta (scrlo),y
+    lda #YELLOW
+    sta (collo),y
+g8_next:
+    iny
+    dec bitcnt
+    bne g8_bit
+    inc g8row
+    lda g8row
+    cmp #8
+    bne g8_row
+    rts
+
+; ---- 8x8 letter bitmaps ----
+glyph_t:
+    !byte %11111111
+    !byte %11111111
+    !byte %00111100
+    !byte %00111100
+    !byte %00111100
+    !byte %00111100
+    !byte %00111100
+    !byte %00111100
+glyph_g:
+    !byte %00111100
+    !byte %01111110
+    !byte %11000011
+    !byte %11000000
+    !byte %11001111
+    !byte %11000011
+    !byte %01111110
+    !byte %00111100
+
+; ---- intro variables ----
+introt:    !byte 0       ; frames left before auto-advancing
+g8row:     !byte 0       ; glyph renderer / wash internals
+g8col:     !byte 0