NextBuild v8

NextBuild

Introduction

NOTE : This documentation is still in progress

NextBuild is a collection of tools and libraries which works with Boriel's ZX Basic compiler for working with the ZX Spectrum Next. Version 8 introduces significant changes, including NEX file generation that contains all your assets in a single file. At the heart of the suite is the NextBuild Library, which facilitates communication directly with the ZX Nexts hardware through optimized assembly routines. Combine this ZX Basic compiler's compiled code produces blazingly fast professional results.

Code is executed with Cspect emulator written by Mike Dailly [1].

The IDE strongly recommended is Visual Studio Code, with setup being straightforward through automatically configured build scripts, tasks, and extensions. NextBuild has been designed to integrate tightly with VSCode. NextBuild will also operate faultlessly with AI editors such as Cursor.

Note, the ZX Basic has been tweaked slightly to work with nicely with the Next's HW. Special conditions are put in place to make sure interrupts or stack locations interfere when paging memory banks or using additional graphics modes. If the nextlib library is used outside the NextBuild suite, it is likely that you will experience issues.

Setup Instructions

Requirements

Visual Studio Code (recommended IDE)
NextBuild tools package (includes Boriel ZX Basic, CSpect emulator, and NextBuild scripts)

A video demonstrating how to correctly setup up is available here : https://www.youtube.com/watch?v=kF_jfE7mAvg

Installation

Clone or download the NextBuild repository
Open the project folder in Visual Studio Code
Install recommended extensions:
- em00k.nextbuild
- eliverlara.andromeda
- maziac.nex-fileviewer
- maziac.asm-code-lens
- alefragnani.bookmarks
- commandvariable.dateTime

Project Structure

/NextBuild
├── zxbasic/         (Boriel ZX Basic compiler)
├── Emu/             (CSpect emulator)
│   └── CSpect/      
├── Scripts/         (NextBuild python scripts)
├── Sources/         (Main sources folder)
│   ├── examples/    (Example code)
    └───└── data/     (Assets: sprites, sounds, etc.)

When launching Visual Studio Code proceed to open a project and select the "Source" directory inside the NextBuildvN folder.

Creating Your First Project

Create a new folder in the Sources directory, then a .bas file inside the new folder.
Add the following template:

'!org=32768

#include <nextlib.bas>

PAPER 0 : INK 7 : CLS 

PRINT "Congratulations!"

do
    ' Main loop
loop

Press Ctrl+Shift+B or select "Run Build Task" from the Terminal menu to compile

Preprocessor Options

These options are set at the top of your `.bas` file:

Option	Description	Default
`!org=nn`	Program start address (24576–65530)	32768
`!heap=nn`	Heap size in bytes	2048
`!opt=n`	Optimization value (0–4)	4
`!bmp=filename`	BMP loading screen for NEX	None
`!copy=filename`	Copy NEX file to specified path	None
`!noemu`	Do not launch emulator after compilation	Emulator launches
`!asm`	Produce ASM output only	NEX file created
`!nosys`	Do not include system variables	Include sysvars
`!nosp`	Do not set up stack pointer	Set up SP

NextLib Library

NextLib provides functions to access ZX Spectrum Next hardware features.

SD Card Access

' Load data from SD card to a memory bank
LoadSDBank(filename$, address, size, offset, bank)
' Load from SD to memory address
LoadSD(filename$, address, size, offset)
' Save from memory to SD card
SaveSD(filename$, address, size)
' Load a BMP file to Layer 2
LoadBMP(filename$)

Layer 2 Graphics

' Enable/disable Layer 2
ShowLayer2(n)  ' 0=off, 1=on
' Clear Layer 2 with color
CLS256(color)
' Scroll Layer 2
ScrollLayer(x, y)
' Set clipping regions
ClipLayer2(x1, x2, y1, y2)
ClipLayerULA(x1, x2, y1, y2)
ClipLayerTile(x1, x2, y1, y2)
ClipSprite(x1, x2, y1, y2)

Tile Operations

There are two types when referring to tile maps. Software tiles are drawn by copying tiles from preloaded banks to the Layer2 graphics screen. Hardware tile maps use a tile system similar found on retro consoles and computers such as the Commodore 64, Nintendo NES and Sega MegaDrive. Below uses software tiles.

' Draw a 16x16 tile from bank
DoTileBank16(x, y, tile_number, bank_number)
' Draw an 8x8 tile from bank
DoTileBank8(x, y, tile_number, bank_number)
' Draw a tile in 320x256 mode
FDoTileBank8(y, x, tile_number, bank_number)
FDoTileBank16(y, x, tile_number, bank_number)

For details on using the hardware tile map see the [Hardware Tilemap] section.

Pixel Operations

' Plot a pixel in Layer 2 (256x192)
PlotL2(x, y, color)
' Plot a pixel in Layer 2 (320x256)
FPlotL2(x, y, color)
' Draw text on Layer 2
L2Text(x, y, string$, bank, mask)
FL2Text(x, y, string$, bank)

Palette Management

' Upload a palette
PalUpload(address, colors_count, offset, bank)

Sprite Operations

' Initialize sprites
InitSprites(total, sprite_address)
InitSprites2(total, sprite_address, bank, sprite_offset)
' Update sprite parameters
UpdateSprite(x, y, sprite_id, pattern, mirror_flip, anchor)
' Remove a sprite
RemoveSprite(sprite_id, visible)

Memory Management

' Get/set MMU banks
MMU8(slot, bank)
MMU16(bank)
GetMMU(slot)
GetReg(register)

Timing and Synchronization

' Wait for vertical retrace
WaitRetrace(frames)
WaitRetrace2(line_number)
' Wait for key press
WaitKey()

Music and Sound Effects

' Initialize music player
InitMusic(player_bank, music_bank, music_offset)
' Initialize sound effects
InitSFX(bank)
' Set up interrupt mode
SetUpIM()
' Control sound
EnableSFX
DisableSFX
EnableMusic
DisableMusic
' Play a sound effect
PlaySFX(effect_number)

Memory Management

MMU Slots

The ZX Spectrum Next divides its memory into 8KB slots that can be mapped to different banks:

Area	Address Range	Default	Description
$0000-$1fff	Slot 0	ROM (255)	Normally ROM. Writes mappable by layer 2. IRQ and NMI routines here.
$2000-$3fff	Slot 1	ROM (255)	Normally ROM. Writes mapped by Layer 2.
$4000-$5fff	Slot 2	10	Normally used for normal/shadow ULA screen.
$6000-$7fff	Slot 3	11	Timex ULA extended attribute/graphics area.
$8000-$9fff	Slot 4	4	Free RAM.
$a000-$bfff	Slot 5	5	Free RAM.
$c000-$dfff	Slot 6	0	Free RAM. Only this area is remappable by 128 memory management.
$e000-$ffff	Slot 7	1	Free RAM. Only this area is remappable by 128 memory management.

RAM Banks

16kb      8kb 
 8-15      16-31       $060000-$07ffff 128K    Extra RAM
16-47      32-95       $080000-$0fffff 512K    1st extra IC RAM (available on unexpanded Next)
48-79      96-159  $100000-$17ffff 512K    2nd extra IC RAM (only available on expanded Next)
80-111    160-223  $180000-$1fffff 512K    3rd extra IC RAM (only available on expanded Next)

NEX File Format

The NEX file is a container that holds your program and all assets in a single file. It is created automatically during the build process.

Configuration Options

The NEX file configuration is generated from preprocessor directives in your source file:

'!org=32768     ' Program start address
'!bmp=intro.bmp ' Loading screen

Extending With Interrupt Mode 2

For advanced applications requiring sound and music, you can enable Interrupt Mode 2:

#define IM2
#include <nextlib.bas>
#include <nextlib_ints.bas>

InitSFX(36)                 ' SFX bank
InitMusic(38, 39, 0000)     ' Player bank, music bank, offset
SetUpIM()                   ' Set up IM2
EnableSFX                   ' Enable SFX playback
EnableMusic                 ' Enable music playback

Examples

Drawing a Sprite

'!org=32768

#define NEX
#include <nextlib.bas>

' Load sprites from SD card to bank 34
LoadSDBank("testsprites.spr", 0, 0, 0, 34)

' Upload 64 sprites from bank 34
InitSprites2(64, 0, 34, 0)

' Main loop
do
    ' Update sprite at position 100,100
    UpdateSprite(100, 100, 0, 0, 0, 128)
    WaitRetrace(1)
loop

Tile-Based Game Screen

'!org=32768
'!heap=2048

#define NEX
#include <nextlib.bas>

' Load tile data
LoadSDBank("tiles.spr", 0, 0, 0, 36)

' Clear Layer 2
CLS256(0)
ShowLayer2(1)

' Draw a 16x16 tilemap
dim map(16, 12) as ubyte

' Initialize map with tile numbers
for y = 0 to 11
    for x = 0 to 15
        ' Set tile numbers (0-63)
        map(x, y) = (x + y) mod 64
    next x
next y

' Draw the map
for y = 0 to 11
    for x = 0 to 15
        DoTileBank16(x, y, map(x, y), 36)
    next x
next y

do
    ' Game loop
    WaitRetrace(1)
loop

Loading from SD Card

' NextBuild simple load from SD card
#include <nextlib.bas>

border 2: paper 0 : ink 0 : cls

' LoadSD(filename,address,size,offset)
ShowLayer2(0)

do 
    LoadSD("screen2.scr",16384,6912,0)
    border 0
    pause 100
loop

Saving to SD Card

#include <nextlib.bas>

dim n as ubyte 

paper 7: ink 0: border 7: cls 

print ink 1;"Lets print some text.." : pause 50 : cls 

for n = 0 to 22
    print "HELLO THERE WORLD ! ! ! ! ! !"
    ink rnd*7
next 

' SaveSD(filename,address,number of bytes)
' lets save the screen 
SaveSD("output.scr",16384,6912)

pause 100 : cls
print ink 1;"Screen saved to SD.."
print ink 1;"Lets load it back.."
pause 100

' LoadSD(filename,address,number of bytes,offset)
LoadSD("output.scr",16384,6912,0)

border 1 : pause 0 

do 
loop

Layer 2 Image Drawing

'!org=24576
' NextBuild Layer2 Template 

#define NEX 
#define IM2 

#include <nextlib.bas>

asm 
    ' setting registers in an asm block means you can use the global equs for register names 
    ' 28mhz, black transparency,sprites on over border,320x256
    nextreg TURBO_CONTROL_NR_07,%11         ' 28 mhz 
    nextreg GLOBAL_TRANSPARENCY_NR_14,$0    ' black 
    nextreg SPRITE_CONTROL_NR_15,%00000011  ' %000    S L U, %11 sprites on over border
    nextreg LAYER2_CONTROL_NR_70,%00000000  ' 5-4 %01 = 320x256x8bpp
end asm 

LoadSDBank("pirate-win.raw",0,0,0,32)       ' load in pirate 1
LoadSDBank("pirate-loss.raw",4096,0,0,32)   ' load in pirate 2

Cls256(0)

do 
    DrawImage(0,0,@image_pirate,0)          ' frame 0 pirate 1
    WaitKey()
    DrawImage(0,0,@image_pirate,1)          ' frame 1 pirate 2
    WaitKey()
loop 

image_pirate:
    asm
        ' bank  spare  
        db  32, 64, 64
        ' offset in bank  
        dw 2
    end asm

File Formats

Sprite Files (.spr)

Binary files containing sprite data. Each 16x16 sprite uses 256 bytes (or 128 bytes for 4-bit sprites).

Palette Files (.pal)

Color palette data files.

Audio Files

.afb: AYFX sound effects bank
.pt3: ProTracker 3 music files

Building and Running

Press Ctrl+Shift+B or select "Run Build Task" to compile your project
If compilation succeeds, CSpect emulator will launch with your program
Press ESC to exit CSpect (F1 enters the debugger)

Debugging

Press F1 in CSpect to enter the debugger
Use the Memory window to inspect memory contents
Set breakpoints with the BBREAK macros in your code or BREAK inside an asm block

Additional Resources

Full ZX Basic Compiler command reference: ZX Basic Documentation
NextBuild Github [2]
NextBuild command lookup [3]
ZX Spectrum Next Hardware Manual for detailed hardware specifications
Example programs in the Sources/examples directory

Common Issues and Solutions

Compilation Error: Check the COMPILE.TXT file for error details
Bank Conflicts: Ensure you're not using overlapping memory banks
Graphics Issues: Check palette settings and Layer 2 initialization
Sound Not Working: Verify IM2 is properly set up and banks are correct

Credits

NextBuild would not exist without the help of many contributors including:

Jose Rodrigez / Boriel
Mike Dailly
D Rimron Soutter
Robin Van HagenGuest
Michael Flash Ware
Kev 9bitColor Brady
Jim Bagley
Dufectu
sol_hsa
ped7g

NextBuild:Main Page

Contents

NextBuild v8

Introduction

NOTE : This documentation is still in progress

Setup Instructions

Requirements

Installation

Project Structure

Creating Your First Project

Preprocessor Options

NextLib Library

SD Card Access

Layer 2 Graphics

Tile Operations

Pixel Operations

Palette Management

Sprite Operations

Memory Management

Timing and Synchronization

Music and Sound Effects

Memory Management

MMU Slots

RAM Banks

NEX File Format

Configuration Options

Extending With Interrupt Mode 2

Examples

Drawing a Sprite

Tile-Based Game Screen

Loading from SD Card

Saving to SD Card

Layer 2 Image Drawing

File Formats

Sprite Files (.spr)

Palette Files (.pal)

Audio Files

Building and Running

Debugging

Additional Resources

Common Issues and Solutions

Credits