Struct TexturePage 

pub struct TexturePage { /* private fields */ }

A texture page: a 256×256 region at a specific VRAM origin, plus a depth.

Hardware constraints (PSX-SPX “GP0 0xE1”):

• x is multiples of 64 pixels → one of 0, 64, 128, …, 960.
• y is either 0 or 256.
• The effective page width shrinks with depth: 64 pixels for 4bpp, 128 for 8bpp, 256 for 15bpp. (Because the texel-fetch address is tpage_x + u / texels_per_halfword, so smaller texels pack into fewer halfwords and hence a narrower span.)

The const constructor catches misaligned X/Y at compile time. A const check across multiple TexturePage consts (to enforce non- overlap) needs const generics that are noisy to express here; runtime collision tooling lives in a follow-up.

Implementations

impl TexturePage

pub const fn new(x: u16, y: u16, depth: TextureDepth) -> Self

Build a TexturePage. Compile-time assertion that x is a multiple of 64 and y is 0 or 256.

pub const fn x(self) -> u16

VRAM X origin (0, 64, …, 960).

pub const fn y(self) -> u16

VRAM Y origin (0 or 256).

pub const fn depth(self) -> TextureDepth

Color depth.

pub const fn covering_rect(self) -> VramRect

VRAM rect this tpage would actually cover at its depth. Useful for sanity-checking that uploaded texture data fits.

pub const fn uv_word(self, semi_trans: u8) -> u16

Encode as the low-16-bits of a textured-primitive UV word (the “tpage” embedded field). Same byte layout as GP0(E1h)’s low 10 bits minus display-disable / dither bits, which we leave to the draw-mode setter. Bits:

  bits 0..3   : tpage X / 64
  bit  4      : tpage Y / 256
  bits 5..6   : semi-transparency mode (0 = half + half)
  bits 7..8   : depth (0=4bpp, 1=8bpp, 2=15bpp)

semi_trans picks the GPU blend mode when a texel’s mask bit is set. 0 is “0.5·bg + 0.5·fg” – the most common.

pub fn apply_as_draw_mode(self)

The full GP0(E1h) draw-mode word. Use this to set the “current” tpage for sprite / rect primitives that don’t embed a tpage of their own.

impl TexturePage

pub const fn uv_tpage_word(self, semi_trans: u8) -> u16

👎Deprecated:

renamed to uv_word

Renamed to TexturePage::uv_word.

Trait Implementations

impl Clone for TexturePage

fn clone(&self) -> TexturePage

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for TexturePage

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for TexturePage

fn eq(&self, other: &TexturePage) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for TexturePage

impl Eq for TexturePage

impl StructuralPartialEq for TexturePage