mirror of
https://github.com/alfishe/amiga-bootcamp.git
synced 2026-06-13 00:26:28 +00:00
21751c0025
Comprehensive technical documentation covering: - Hardware: OCS/ECS/AGA custom chip registers, Copper & Blitter deep dives - Boot sequence: cold boot through startup-sequence - Binary format: HUNK executable spec, relocation, debug info - Linking & ABI: .fd files, LVO tables, register calling conventions - Exec kernel: tasks, interrupts, memory, signals, semaphores - AmigaDOS: file I/O, FFS/OFS layout, CLI/Shell scripting - Graphics: planar bitmaps, Copper programming, HAM/EHB modes - Intuition: screens, windows, IDCMP, BOOPSI - Devices: trackdisk, SCSI, serial, timer, audio, keyboard - Libraries: utility, expansion, IFFParse, locale, ARexx - Networking: bsdsocket API, SANA-II, TCP/IP stack comparison - Toolchain: GCC, vasm/vlink, SAS/C, NDK, debugging - Reverse engineering: IDA/Ghidra setup, compiler fingerprints, case studies - CPU & MMU: 68040/060 emulation libs, PMMU, cache management - Driver development: SANA-II, Picasso96/RTG, AHI audio All files include breadcrumb navigation. No local paths or proprietary content.
110 lines
2.8 KiB
Markdown
110 lines
2.8 KiB
Markdown
[← Home](../README.md) · [Graphics](README.md)
|
|
|
|
# Animation — GEL System: BOBs, VSprites, AnimObs
|
|
|
|
## Overview
|
|
|
|
The **GEL (Graphics ELement)** system provides high-level animated sprite and bitmap overlay support. It manages VSprites (virtual sprites that can use hardware or software rendering), BOBs (Blitter OBjects — arbitrary-sized bitmaps overlaid on a playfield), and AnimObs (animation objects with sequencing).
|
|
|
|
---
|
|
|
|
## VSprite
|
|
|
|
```c
|
|
/* graphics/gels.h — NDK39 */
|
|
struct VSprite {
|
|
struct VSprite *NextVSprite;
|
|
struct VSprite *PrevVSprite;
|
|
struct VSprite *DrawPath;
|
|
struct VSprite *ClearPath;
|
|
WORD OldY, OldX; /* previous position */
|
|
WORD Flags; /* VSPRITE, SAVEBACK, OVERLAY, MUSTDRAW */
|
|
WORD Y, X; /* current position */
|
|
WORD Height;
|
|
WORD Width; /* width in words */
|
|
WORD Depth;
|
|
WORD MeMask; /* collision mask */
|
|
WORD HitMask;
|
|
WORD *ImageData; /* sprite image */
|
|
WORD *BorderLine; /* collision border */
|
|
WORD *CollMask; /* collision mask data */
|
|
WORD *SprColors; /* colour table */
|
|
struct Bob *VSBob; /* if this VSprite backs a BOB */
|
|
BYTE PlanePick;
|
|
BYTE PlaneOnOff;
|
|
/* ... */
|
|
};
|
|
```
|
|
|
|
---
|
|
|
|
## BOB (Blitter Object)
|
|
|
|
```c
|
|
struct Bob {
|
|
WORD Flags;
|
|
WORD *SaveBuffer; /* background save buffer */
|
|
WORD *ImageShadow; /* shadow mask for cookie-cut */
|
|
struct Bob *Before;
|
|
struct Bob *After;
|
|
struct VSprite *BobVSprite; /* associated VSprite */
|
|
struct AnimComp *BobComp; /* if part of animation */
|
|
struct DBufPacket *DBuffer; /* double-buffer packet */
|
|
};
|
|
```
|
|
|
|
---
|
|
|
|
## Usage Pattern
|
|
|
|
```c
|
|
struct GelsInfo gi;
|
|
struct VSprite headVS, tailVS;
|
|
|
|
/* Initialise GEL system: */
|
|
InitGels(&headVS, &tailVS, &gi);
|
|
rp->GelsInfo = &gi;
|
|
|
|
/* Add a VSprite/BOB: */
|
|
AddVSprite(&myVSprite, rp);
|
|
/* or */
|
|
AddBob(&myBob, rp);
|
|
|
|
/* Each frame: */
|
|
SortGList(rp); /* sort by Y position */
|
|
DrawGList(rp, &vp); /* render all GELs */
|
|
WaitTOF(); /* sync to vertical blank */
|
|
|
|
/* Cleanup: */
|
|
RemVSprite(&myVSprite);
|
|
/* or */
|
|
RemBob(&myBob);
|
|
```
|
|
|
|
---
|
|
|
|
## AnimOb — Animation Sequences
|
|
|
|
```c
|
|
struct AnimOb {
|
|
struct AnimOb *NextOb;
|
|
struct AnimOb *PrevOb;
|
|
LONG Clock; /* frame counter */
|
|
WORD AnOldY, AnOldX;
|
|
WORD AnY, AnX; /* current position */
|
|
WORD YVel, XVel; /* velocity */
|
|
WORD YAccel, XAccel; /* acceleration */
|
|
WORD RingYTrans; /* ring buffer Y translation */
|
|
WORD RingXTrans;
|
|
struct AnimComp *HeadComp; /* component chain */
|
|
/* ... */
|
|
};
|
|
```
|
|
|
|
---
|
|
|
|
## References
|
|
|
|
- NDK39: `graphics/gels.h`, `graphics/gelsinternal.h`
|
|
- ADCD 2.1: `InitGels`, `AddVSprite`, `AddBob`, `SortGList`, `DrawGList`
|
|
- *Amiga ROM Kernel Reference Manual: Libraries* — GELs chapter
|