new workspace

wgui/src/transform_stack.rs

@@ -0,0 +1,51 @@
+use glam::Vec2;
+
+#[derive(Default, Copy, Clone)]
+pub struct Transform {
+	pub pos: Vec2,
+	pub transform: glam::Mat4,
+
+	pub dim: Vec2, // for convenience
+}
+
+const TRANSFORM_STACK_MAX: usize = 64;
+pub struct TransformStack {
+	pub stack: [Transform; TRANSFORM_STACK_MAX],
+	top: u8,
+}
+
+impl TransformStack {
+	pub fn new() -> Self {
+		Self {
+			stack: [Default::default(); TRANSFORM_STACK_MAX],
+			top: 1,
+		}
+	}
+
+	pub fn push(&mut self, mut t: Transform) {
+		assert!(self.top < TRANSFORM_STACK_MAX as u8);
+		let idx = (self.top - 1) as usize;
+		t.pos += self.stack[idx].pos;
+		self.stack[self.top as usize] = t;
+		self.top += 1;
+	}
+
+	pub fn pop(&mut self) {
+		assert!(self.top > 0);
+		self.top -= 1;
+	}
+
+	pub fn get(&self) -> &Transform {
+		&self.stack[(self.top - 1) as usize]
+	}
+
+	pub fn get_pos(&self) -> Vec2 {
+		self.stack[(self.top - 1) as usize].pos
+	}
+}
+
+impl Default for TransformStack {
+	fn default() -> Self {
+		Self::new()
+	}
+}