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Remove per-call overhead from API access and text conversion

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Two hot-path optimizations for the device's Cortex-M7 (and debug simulator
builds):

- The ten sub-API pointers are cached once in Playdate.initialize(with:);
  wrapper accessors now return UnsafePointer and call sites read a single
  field through it, instead of unwrapping the optional API struct and
  copying a whole sub-API struct of function pointers on every call.
  Nested sub-APIs (sound classes, effects, video, tilemap, http/tcp)
  derive from the cached pointers with one field load.

- String -> C conversions (withPlaydateCString, and a new withPlaydateUTF8
  used by the text drawing/measuring APIs) use withUnsafeTemporaryAllocation
  instead of building a ContiguousArray, so logging and drawText in the
  update loop no longer heap-allocate per call. Verified within the
  Embedded Swift subset by the device cross-compile.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
javier
2026-07-25 07:23:19 +02:00
co-authored by Claude Fable 5
parent e4e99cc894
commit d914e0f8fb
20 changed files with 682 additions and 643 deletions
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Sources/PlayDate/GraphicsFont.swift
+13 -15
View File
@@ -21,7 +21,7 @@ extension Graphics {
/// Loads a font from a file.
public convenience init(path: String) throws(PlaydateError) {
var error: UnsafePointer<CChar>?
let pointer = path.withPlaydateCString { gfx.loadFont.unsafelyUnwrapped($0, &error) }
let pointer = path.withPlaydateCString { gfx.pointee.loadFont.unsafelyUnwrapped($0, &error) }
guard let pointer else { throw PlaydateError(cString: error) }
self.init(pointer: pointer)
}
@@ -32,7 +32,7 @@ extension Graphics {
let copy = UnsafeMutableRawPointer.allocate(byteCount: data.count, alignment: 4)
copy.copyMemory(from: data.baseAddress.unsafelyUnwrapped, byteCount: data.count)
let fontData = OpaquePointer(copy)
guard let pointer = gfx.makeFontFromData.unsafelyUnwrapped(
guard let pointer = gfx.pointee.makeFontFromData.unsafelyUnwrapped(
fontData, wide ? 1 : 0, Int32(data.count)) else {
copy.deallocate()
return nil
@@ -48,25 +48,23 @@ extension Graphics {
/// The font's glyph height in pixels.
public var height: Int {
Int(gfx.getFontHeight.unsafelyUnwrapped(pointer))
Int(gfx.pointee.getFontHeight.unsafelyUnwrapped(pointer))
}
/// The width of `text` when drawn with this font.
public func textWidth(_ text: String, tracking: Int = 0) -> Int {
let utf8 = ContiguousArray(text.utf8)
return utf8.withUnsafeBufferPointer { buffer in
Int(gfx.getTextWidth.unsafelyUnwrapped(pointer, buffer.baseAddress, buffer.count,
kUTF8Encoding, Int32(tracking)))
text.withPlaydateUTF8 { bytes, count in
Int(gfx.pointee.getTextWidth.unsafelyUnwrapped(pointer, bytes, count,
kUTF8Encoding, Int32(tracking)))
}
}
/// The height of `text` when wrapped to `maxWidth` with this font.
public func textHeight(_ text: String, maxWidth: Int, wrap: TextWrappingMode = .word,
tracking: Int = 0, extraLeading: Int = 0) -> Int {
let utf8 = ContiguousArray(text.utf8)
return utf8.withUnsafeBufferPointer { buffer in
Int(gfx.getTextHeightForMaxWidth.unsafelyUnwrapped(
pointer, buffer.baseAddress, buffer.count, Int32(maxWidth), kUTF8Encoding,
text.withPlaydateUTF8 { bytes, count in
Int(gfx.pointee.getTextHeightForMaxWidth.unsafelyUnwrapped(
pointer, bytes, count, Int32(maxWidth), kUTF8Encoding,
wrap.cValue, Int32(tracking), Int32(extraLeading)))
}
}
@@ -74,7 +72,7 @@ extension Graphics {
/// The page containing glyph data for the character `codepoint`
/// belongs to. The page references data owned by the font.
public func page(for codepoint: UInt32) -> FontPage? {
guard let page = gfx.getFontPage.unsafelyUnwrapped(pointer, codepoint) else { return nil }
guard let page = gfx.pointee.getFontPage.unsafelyUnwrapped(pointer, codepoint) else { return nil }
return FontPage(pointer: page, font: self)
}
@@ -83,7 +81,7 @@ extension Graphics {
public func glyph(for codepoint: UInt32) -> (glyph: Glyph, bitmap: Bitmap?, advance: Int)? {
var bitmap: OpaquePointer?
var advance: Int32 = 0
guard let glyph = gfx.getFontGlyph.unsafelyUnwrapped(pointer, codepoint, &bitmap, &advance) else {
guard let glyph = gfx.pointee.getFontGlyph.unsafelyUnwrapped(pointer, codepoint, &bitmap, &advance) else {
return nil
}
return (Glyph(pointer: glyph, font: self),
@@ -102,7 +100,7 @@ extension Graphics {
public func glyph(for codepoint: UInt32) -> (glyph: Glyph, bitmap: Bitmap?, advance: Int)? {
var bitmap: OpaquePointer?
var advance: Int32 = 0
guard let glyph = gfx.getPageGlyph.unsafelyUnwrapped(pointer, codepoint, &bitmap, &advance) else {
guard let glyph = gfx.pointee.getPageGlyph.unsafelyUnwrapped(pointer, codepoint, &bitmap, &advance) else {
return nil
}
return (Glyph(pointer: glyph, font: font),
@@ -119,7 +117,7 @@ extension Graphics {
/// The kerning adjustment between this glyph and the next character.
public func kerning(glyphCode: UInt32, nextCode: UInt32) -> Int {
Int(gfx.getGlyphKerning.unsafelyUnwrapped(pointer, glyphCode, nextCode))
Int(gfx.pointee.getGlyphKerning.unsafelyUnwrapped(pointer, glyphCode, nextCode))
}
}
}