`gba::object` Reference

gba::object is the regular (non-affine) OAM object entry type from <gba/video>.

Use it with gba::obj_mem when you want standard sprite placement with optional horizontal/vertical flipping.

For affine objects, see gba::object_affine.

Include

#include <gba/video>

Type summary

struct object {
    // Attribute 0
    unsigned short y : 8;
    bool : 1;
    bool disable : 1;
    gba::mode mode : 2;
    bool mosaic : 1;
    gba::depth depth : 1;
    gba::shape shape : 2;

    // Attribute 1
    unsigned short x : 9;
    short : 3;
    bool flip_x : 1;
    bool flip_y : 1;
    unsigned short size : 2;

    // Attribute 2
    unsigned short tile_index : 10;
    unsigned short background : 2;
    unsigned short palette_index : 4;
};

sizeof(gba::object) == 6 bytes.

Typical usage

gba::obj_mem[0] = {
    .y = 80,
    .x = 120,
    .shape = gba::shape_square,
    .size = 1,          // 16x16 for square sprites
    .depth = gba::depth_4bpp,
    .tile_index = 0,
    .palette_index = 0,
};

Field notes

disable: hide this object without clearing its other fields.
mode: object blend/window mode (mode_normal, mode_blend, mode_window).
depth: choose depth_4bpp (16-colour banked palette) or depth_8bpp (256-colour OBJ palette).
shape + size: together determine dimensions.
flip_x/flip_y: valid for regular objects.
background: OBJ priority relative to backgrounds (0 highest, 3 lowest).

Regular vs affine comparison

Aspect	`gba::object` (regular)	`gba::object_affine`
Typed OAM view	`gba::obj_mem`	`gba::obj_aff_mem`
Attr0 mode bit	`disable` hide flag	`affine` enabled, optional `double_size`
Attr1 control bits	`flip_x` / `flip_y`	`affine_index` (`0..31`)
Rotation/scaling	Not supported	Supported via affine matrix
Transform source	Flip bits only	`mem_obj_affa/b/c/d` entry selected by `affine_index`
Shared fields	`x`, `y`, `shape`, `size`, `tile_index`, `background`, `palette_index`, `depth`, `mode`, `mosaic`	Same shared fields
Best fit	Standard sprites, mirroring, UI, low overhead	Rotating/scaling sprites, camera-facing effects

Shape/size table

Shape	Size 0	Size 1	Size 2	Size 3
Square	8x8	16x16	32x32	64x64
Wide	16x8	32x8	32x16	64x32
Tall	8x16	8x32	16x32	32x64

gba::obj_mem - typed OAM as object[128]
gba::tile_index(ptr) - compute OBJ tile index from an OBJ VRAM pointer
gba::mem_vram_obj - raw object VRAM

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