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sx/library/modules/ui/events.sx
agra cd2ab1c4b6 ui: platform-neutral Keycode enum; map SDL keycodes once
KeyData.key was a raw u32 carrying SDL_Keycode values, so app code had to reinterpret it as SDL_Keycode (xx e.key) — a leaky, unchecked cross-platform cast only valid because the backend happened to be SDL. Add a neutral Keycode enum; translate_sdl_event maps SDL_Keycode to it via keycode_from_sdl. App code compares e.key == .escape with no platform type and no cast; a new backend maps its own native codes in one place.
2026-05-31 10:42:55 +03:00

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#import "modules/std.sx";
#import "modules/sdl3.sx";
#import "modules/ui/types.sx";
MouseButton :: enum {
none;
left;
middle;
right;
}
MouseButtonData :: struct { position: Point; button: MouseButton; }
MouseMotionData :: struct { position: Point; delta: Point; }
MouseWheelData :: struct { position: Point; delta: Point; }
// Platform-neutral keycode. Each backend translates its native codes to this
// (see `keycode_from_sdl`), so app code never depends on a platform key enum.
Keycode :: enum {
unknown;
escape;
enter;
space;
tab;
backspace;
delete;
left;
right;
up;
down;
}
KeyData :: struct { key: Keycode; }
ResizeData :: struct { size: Size; }
Event :: enum {
none;
quit;
mouse_down: MouseButtonData;
mouse_up: MouseButtonData;
mouse_moved: MouseMotionData;
mouse_wheel: MouseWheelData;
key_down: KeyData;
key_up: KeyData;
text_input: string;
window_resize: ResizeData;
}
event_position :: (e: *Event) -> ?Point {
if e.* == {
case .mouse_down: (d) { return d.position; }
case .mouse_up: (d) { return d.position; }
case .mouse_moved: (d) { return d.position; }
case .mouse_wheel: (d) { return d.position; }
}
null;
}
// Map a platform (SDL) keycode to the neutral `Keycode`. Only the keys the app
// consumes are mapped; everything else is `.unknown`. Letters/digits arrive via
// `text_input`, not here.
// TODO: extend as more keys are needed.
keycode_from_sdl :: (k: SDL_Keycode) -> Keycode {
if k == {
case .escape: return .escape;
case .return_key: return .enter;
case .space: return .space;
case .tab: return .tab;
case .backspace: return .backspace;
case .delete_key: return .delete;
case .left: return .left;
case .right: return .right;
case .up: return .up;
case .down: return .down;
}
.unknown;
}
// Translate SDL_Event → our Event type
translate_sdl_event :: (sdl: *SDL_Event) -> Event {
if sdl.* == {
case .quit: {
return .quit;
}
case .key_down: (data) {
return .key_down(.{ key = keycode_from_sdl(data.key) });
}
case .key_up: (data) {
return .key_up(.{ key = keycode_from_sdl(data.key) });
}
case .mouse_motion: (data) {
return .mouse_moved(.{
position = .{ x = data.x, y = data.y },
delta = .{ x = data.xrel, y = data.yrel }
});
}
case .mouse_button_down: (data) {
btn :MouseButton = if data.button == {
case 1: .left;
case 2: .middle;
case 3: .right;
else: .none;
};
return .mouse_down(.{
position = .{ x = data.x, y = data.y },
button = btn
});
}
case .mouse_button_up: (data) {
btn :MouseButton = if data.button == {
case 1: .left;
case 2: .middle;
case 3: .right;
else: .none;
};
return .mouse_up(.{
position = .{ x = data.x, y = data.y },
button = btn
});
}
case .mouse_wheel: (data) {
return .mouse_wheel(.{
position = .{ x = data.mouse_x, y = data.mouse_y },
delta = .{ x = data.x, y = data.y }
});
}
case .window_resized: (data) {
return .window_resize(.{
size = .{ width = xx data.data1, height = xx data.data2 }
});
}
}
.none;
}