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Learn how to create stunning loading screens for your Amstrad CPC games using PNG images that are automatically converted to the native SCN format.

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Overview

Loading screens are full-screen images displayed while your game loads. DevCPC automatically converts PNG images to SCN (screen) format and adds them to your DSK image.

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Quick Start

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1. Create Your PNG

Create a PNG image with the correct resolution for your chosen mode:
  • Mode 0: 160x200 pixels, 16 colors
  • Mode 1: 320x200 pixels, 4 colors
  • Mode 2: 640x200 pixels, 2 colors

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2. Configure devcpc.conf

# Set CPC mode
MODE=0

# Specify screen directory
LOADER_SCREEN="assets/screen"

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3. Place PNG Files

mkdir -p assets/screen
cp title.png assets/screen/

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4. Build Project

devcpc build
The build process:
  1. Finds all PNG files in assets/screen/
  2. Converts each to SCN format
  3. Saves to obj/ directory
  4. Adds to DSK automatically
  5. Creates .info files with palette data

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Screen Modes

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Mode 0: 160x200, 16 Colors

Best for: Colorful graphics, logos, detailed images 
MODE=0
PNG requirements:
  • Resolution: 160x200 pixels exactly
  • Maximum colors: 16 from CPC palette
  • Each pixel = 2 bytes in video memory
Use case: 
10 MODE 0
20 LOAD"TITLE.SCN",&C000
30 REM Full color title screen

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Mode 1: 320x200, 4 Colors

Best for: Sharp text, clean graphics, retro aesthetic 
MODE=1
PNG requirements:
  • Resolution: 320x200 pixels exactly
  • Maximum colors: 4 from CPC palette
  • Higher resolution, fewer colors
Use case: 
10 MODE 1
20 LOAD"LOGO.SCN",&C000
30 REM Sharp company logo

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Mode 2: 640x200, 2 Colors

Best for: Text adventures, high-res graphics, monochrome art 
MODE=2
PNG requirements:
  • Resolution: 640x200 pixels exactly
  • Maximum colors: 2 from CPC palette
  • Highest resolution
Use case: 
10 MODE 2
20 LOAD"TEXT.SCN",&C000
30 REM High resolution text screen

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CPC Color Palette

Use these RGB values in your image editor: 
INK 0  = Black         (0,0,0)
INK 1  = Blue          (0,0,128)
INK 2  = Bright Blue   (0,0,255)
INK 3  = Red           (128,0,0)
INK 4  = Magenta       (128,0,128)
INK 5  = Mauve         (128,0,255)
INK 6  = Bright Red    (255,0,0)
INK 7  = Purple        (255,0,128)
INK 8  = Bright Magenta(255,0,255)
INK 9  = Green         (0,128,0)
INK 10 = Cyan          (0,128,128)
INK 11 = Sky Blue      (0,128,255)
INK 12 = Yellow        (128,128,0)
INK 13 = Gray          (128,128,128)
INK 14 = Pastel Blue   (128,128,255)
INK 15 = Orange        (255,128,0)
INK 16 = Pink          (255,128,128)
INK 17 = Pastel Magenta(255,128,255)
INK 18 = Bright Green  (0,255,0)
INK 19 = Sea Green     (0,255,128)
INK 20 = Bright Cyan   (0,255,255)
INK 21 = Lime          (128,255,0)
INK 22 = Pastel Green  (128,255,128)
INK 23 = Pastel Cyan   (128,255,255)
INK 24 = Bright Yellow (255,255,0)
INK 25 = Pastel Yellow (255,255,128)
INK 26 = White         (255,255,255)

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Creating PNG in GIMP

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Step 1: New Image

  1. File → New
  2. Width: 160 (Mode 0) or 320 (Mode 1) or 640 (Mode 2)
  3. Height: 200
  4. Advanced Options → Fill with: Transparency or Background color

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Step 2: Set Up Palette

  1. Windows → Dockable Dialogs → Palettes
  2. Create “CPC Palette” with colors from table above
  3. Image → Mode → Indexed
  4. Use custom palette with max colors for your mode

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Step 3: Create Artwork

  • Use pencil tool for pixel-perfect control
  • Zoom in (400% or more) for detail work
  • Use only palette colors
  • Check color count: Image → Mode → Indexed → Colormap

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Step 4: Export

  1. File → Export As
  2. Choose PNG format
  3. Export → Accept defaults

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Build Output

When you run devcpc build, you’ll see: 
═══════════════════════════════════════
  Convertir Pantallas de Carga
═══════════════════════════════════════

ℹ Ruta:  assets/screen
ℹ Modo:  0 (160x200, 16 colores)

→ Convirtiendo title.png...
✓ title.scn generado (16384 bytes)
ℹ Paleta: 12 colores detectados

→ Convirtiendo loading.png...
✓ loading.scn generado (16384 bytes)
ℹ Paleta: 8 colores detectados

✓ 2 pantalla(s) convertida(s)

→ Añadiendo pantallas al DSK...
✓ title.scn añadido
✓ loading.scn añadido

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Generated Files

obj/
├── title.scn           # 16384 byte screen data
├── title.scn.info      # Palette information
├── loading.scn
└── loading.scn.info

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Palette Info File (.scn.info)

Each screen generates an .info file: 
FILE: title.scn
WIDTH: 160
HEIGHT: 200
MODE: 0
PALETTE COLORS: 8

FW              HW              RGB
0               0x14    (0, 0, 0)
24              0x0A    (255, 255, 0)
6               0x04    (255, 0, 0)
1               0x02    (0, 0, 128)
18              0x12    (0, 255, 0)
11              0x0B    (0, 128, 255)
26              0x1A    (255, 255, 255)
13              0x0D    (128, 128, 128)

; ASM HW palette
db 0x14, 0x0A, 0x04, 0x02, 0x12, 0x0B, 0x1A, 0x0D

' BASIC palette
INK 0,0: INK 1,24: INK 2,6: INK 3,1: INK 4,18: INK 5,11: INK 6,26: INK 7,13

// C palette
hwpal = { 0x14, 0x0A, 0x04, 0x02, 0x12, 0x0B, 0x1A, 0x0D }
Use this to set the correct palette when loading the screen.

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Loading Screens in BASIC

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Simple Loading Screen

10 REM Load title screen
20 MODE 0
30 LOAD"TITLE.SCN",&C000
40 REM Set palette from .info file
50 INK 0,0: INK 1,24: INK 2,6: INK 3,1
60 INK 4,18: INK 5,11: INK 6,26: INK 7,13
70 REM Wait 3 seconds
80 FOR i=1 TO 150: NEXT i
90 REM Continue loading
100 LOAD"8BP0.BIN"

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With Border

10 MODE 0
20 BORDER 0
30 LOAD"TITLE.SCN",&C000
40 INK 0,0: INK 1,24: INK 2,6

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Animated Loading Message

10 MODE 0
20 LOAD"TITLE.SCN",&C000
30 INK 0,0: INK 1,24: INK 2,6
40 FOR i=1 TO 3
50   LOCATE 10,20: PRINT "LOADING";
60   FOR j=1 TO 20: NEXT j
70   LOCATE 10,20: PRINT "LOADING.";
80   FOR j=1 TO 20: NEXT j
90   LOCATE 10,20: PRINT "LOADING..";
100  FOR j=1 TO 20: NEXT j
110  LOCATE 10,20: PRINT "LOADING...";
120  FOR j=1 TO 20: NEXT j
130 NEXT i
140 LOAD"8BP0.BIN"

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Multiple Screens

10 REM Title screen
20 MODE 0
30 BORDER 0
40 LOAD"TITLE.SCN",&C000
50 INK 0,0: INK 1,24: INK 2,6
60 LOCATE 12,22: PRINT "PRESS ANY KEY"
70 CALL &BB18: REM Wait for key
80 REM Loading screen
90 LOAD"LOADING.SCN",&C000
100 INK 0,0: INK 1,1: INK 2,18
110 LOCATE 10,20: PRINT "LOADING GAME..."
120 REM Load game
130 LOAD"8BP0.BIN"
140 CALL &6B78

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Loading Screens from Assembly

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Direct Load

; Load screen to video memory
ld hl, screen_data
ld de, &C000
ld bc, 16384
ldir

screen_data:
    incbin "title.scn"

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With Palette Setup

; Set mode 0
ld a, 0
call &BC0E          ; SCR SET MODE

; Set border
ld b, 0
ld c, 0
call &BC38          ; SCR SET BORDER

; Load screen
ld hl, title_scn
ld de, &C000
ld bc, 16384
ldir

; Set palette (from .info file)
ld hl, palette
ld b, 8             ; 8 colors
ld c, 0             ; Start with PEN 0
set_pal_loop:
    ld a, c
    push bc
    push hl
    ld b, a         ; PEN number
    ld a, (hl)      ; Hardware color
    ld c, a
    call &BC32      ; SCR SET INK
    pop hl
    pop bc
    inc hl
    inc c
    djnz set_pal_loop

title_scn:
    incbin "title.scn"

palette:
    db 0x14, 0x0A, 0x04, 0x02, 0x12, 0x0B, 0x1A, 0x0D

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Fast Decrunch (Compressed Screens)

For larger projects, compress screens: 
; Decompress screen (example using Exomizer)
ld hl, compressed_screen
ld de, &C000
call exo_decrunch

compressed_screen:
    incbin "title.scn.exo"

; Include exomizer decrunch routine
include "exomizer.asm"

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Loading Screens from Tape (CDT)

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Configuration

# devcpc.conf
CDT="${PROJECT_NAME}.cdt"
CDT_FILES="title.scn loader.bas 8BP0.bin"

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Order Matters

File order on tape:
1. title.scn    - Screen loads first
2. loader.bas   - BASIC program
3. 8BP0.bin     - Game binary

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Loading from Tape

10 REM Load from tape
20 MODE 0
30 LOAD"TITLE.SCN",&C000
40 INK 0,0: INK 1,24
50 REM Screen now visible while rest loads
60 LOAD"8BP0.BIN"
70 CALL &6B78
On CPC: 
RUN"

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Advanced Techniques

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Fade In Effect

10 MODE 0
20 LOAD"TITLE.SCN",&C000
30 REM Fade in from black
40 FOR i=0 TO 7
50   INK 0,0: INK 1,i*3: INK 2,i*3+1: INK 3,i*3+2
60   FOR j=1 TO 10: NEXT j
70 NEXT i
80 REM Final palette
90 INK 0,0: INK 1,24: INK 2,6: INK 3,1

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Scanline Effect

; Draw screen with scanline effect
ld hl, screen_data
ld de, &C000
ld b, 200           ; 200 lines
load_line_loop:
    push bc
    
    ; Copy one line (80 bytes in Mode 0)
    ld bc, 80
    ldir
    
    ; Wait for scanline
    call wait_scanline
    
    pop bc
    djnz load_line_loop

wait_scanline:
    ld b, 10
wait_loop:
    djnz wait_loop
    ret

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Screen Transition

10 REM Wipe transition between screens
20 MODE 0
30 LOAD"SCREEN1.SCN",&C000
40 CALL &BB18: REM Wait for key
50 REM Wipe from bottom to top
60 FOR y=199 TO 0 STEP -4
70   LOAD"SCREEN2.SCN",&C000+y*80
80 NEXT y

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Memory Considerations

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Screen Memory Layout

Mode 0 (160x200, 16 colors):
  &C000 - &FFFF = 16KB video memory
  SCN file = 16384 bytes (full screen)

Mode 1 (320x200, 4 colors):
  &C000 - &FFFF = 16KB video memory
  SCN file = 16384 bytes (full screen)

Mode 2 (640x200, 2 colors):
  &C000 - &FFFF = 16KB video memory
  SCN file = 16384 bytes (full screen)
All modes use the same size because they use the full video memory space.

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Loading Multiple Screens

If you have many screens, consider:
  1. Compression: Use Exomizer or similar
  2. Streaming: Load screens on-demand
  3. Partial Updates: Only update changed areas

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Troubleshooting

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Screen Not Displaying

Problem: Black screen after LOAD Solutions:
  • Ensure MODE is set before LOAD
  • Check load address is &C000
  • Verify PNG dimensions match mode
  • Set palette with INK commands

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Wrong Colors

Problem: Colors don’t match PNG Solutions:
  • Copy palette from .scn.info file
  • Set INK colors AFTER MODE command
  • Use exact CPC RGB values in PNG

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PNG Conversion Fails

Problem: “Color not in CPC palette” Solutions:
  • Use only CPC palette colors
  • Install Pillow: pip3 install Pillow
  • Reduce colors in image editor
  • Use indexed color mode

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File Too Large

Problem: DSK is full Solutions:
  • Remove unused screens
  • Use compression
  • Create multiple DSK images
  • Use CDT (tape) for more space

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Best Practices

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1. Optimize File Count

# Only include essential screens
assets/screen/
├── title.png      # Title/menu
├── loading.png    # Loading indicator
└── gameover.png   # Game over

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2. Name Files Clearly

# Good naming
title.png
loading.png
level1.png
credits.png

# Avoid
screen1.png
img2.png
test.png

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3. Test on Real Hardware

  • Colors may look different on CRT
  • Test brightness levels
  • Check border colors
  • Verify timing

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4. Provide Feedback

10 MODE 0
20 LOAD"TITLE.SCN",&C000
30 PRINT "LOADING GAME"
40 LOAD"8BP0.BIN"
50 PRINT "DONE!"

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Complete Example

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Project Structure

my-game/
├── devcpc.conf
├── src/
│   └── loader.bas
└── assets/
    └── screen/
        ├── title.png       # 160x200, 16 colors
        ├── loading.png     # 160x200, 8 colors
        └── credits.png    # 160x200, 4 colors

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devcpc.conf

PROJECT_NAME="my_game"
BUILD_LEVEL=0
ASM_PATH="src/asm/make_all_mygame.asm"
BASIC_PATH="src"
MODE=0
LOADER_SCREEN="assets/screen"
DSK="${PROJECT_NAME}.dsk"

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loader.bas

10 REM Title Screen
20 MODE 0: BORDER 0
30 LOAD"TITLE.SCN",&C000
40 INK 0,0: INK 1,24: INK 2,6: INK 3,1: INK 4,18
50 LOCATE 15,22: PRINT "PRESS SPACE"
60 IF INKEY(47)<>0 THEN GOTO 60
70 REM Loading Screen
80 LOAD"LOADING.SCN",&C000
90 INK 0,0: INK 1,1: INK 2,11
100 LOCATE 12,20: PRINT "LOADING..."
110 MEMORY 23599
120 LOAD"8BP0.BIN"
130 CALL &6B78
140 REM Game runs...
150 REM Credits
160 MODE 0: BORDER 0
170 LOAD"CREDITS.SCN",&C000
180 INK 0,0: INK 1,26
190 LOCATE 15,24: PRINT "THE END"
200 CALL &BB18

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Build and Test

devcpc build
devcpc run

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