Initial gui commit.

Very much WIP trying to find a good way to keep components self
contained and composable.

src/gui/gui.odin

@@ -0,0 +1,53 @@
+package gui
+
+import m "../machine"
+import rl "vendor:raylib"
+
+// Initial window size
+WINDOW_WIDTH  :: 1920
+WINDOW_HEIGHT :: 1080
+
+// Initialize main the gui 'window'
+init_gui :: proc(s: ^m.System) {
+	rl.SetConfigFlags({.WINDOW_RESIZABLE})
+	rl.InitWindow(WINDOW_WIDTH, WINDOW_HEIGHT, "raylib")
+	rl.InitAudioDevice()
+	rl.SetTargetFPS(60)
+
+	// Draw each of the components in its own window within the main window
+	for !rl.WindowShouldClose() {
+		// Recalculate layout each frame based on current window size
+		// Pass these down to gui functions so they can setup their sizes?
+		screen_width  := f32(rl.GetScreenWidth())
+		screen_height := f32(rl.GetScreenHeight())
+
+		sidebar_width := screen_width * 0.20
+
+		display_rect := rl.Rectangle{
+		    x = sidebar_width,
+		    y = 0,
+		    width = screen_width - (sidebar_width * 2),
+		    height = screen_height * 0.30,
+		}
+
+		rl.BeginDrawing()
+		rl.ClearBackground(rl.BLACK)
+
+		// TODO: move this out / make better
+		// --------------------------------------
+		// CPU cycles
+		for _ in 0..<12 {
+			m.handle_input(s)
+			m.cycle(s)
+		}
+		// --------------------------------------
+
+		// run each gui "component"
+		gui_screen(display_rect, s)
+
+		rl.EndDrawing()
+	}
+
+	rl.CloseAudioDevice()
+	rl.CloseWindow()
+}