movement and sprite flipping

engine/input.odin

@@ -0,0 +1,28 @@
+package engine
+
+import sdl "vendor:sdl3"
+
+Key :: enum {
+	A,
+	D,
+	Left,
+	Right,
+}
+
+key_down :: proc(key: Key) -> bool {
+	keys := sdl.GetKeyboardState(nil)
+	if keys == nil do return false
+
+	scan_code: sdl.Scancode
+	switch key {
+	case .A:
+		scan_code = .A
+	case .D:
+		scan_code = .D
+	case .Left:
+		scan_code = .LEFT
+	case .Right:
+		scan_code = .RIGHT
+	}
+	return keys[scan_code]
+}

engine/sprite.odin

@@ -11,6 +11,7 @@ Sprite :: struct {
 	clip:     string,
 	frame:    int,
 	time:     f32,
+	flip_x:   bool,
 }
 
 spawn_sprite :: proc(
@@ -119,6 +120,7 @@ draw_sprite :: proc(app: ^App, sprite: ^Sprite) {
 	v0 := f32(rect[1]) / tex_h
 	u1 := f32(rect[0] + rect[2]) / tex_w
 	v1 := f32(rect[1] + rect[3]) / tex_h
+	if sprite.flip_x do u0, u1 = u1, u0
 
 	// Two triangles: (0,1,2) and (0,2,3)
 	verts := [6]Vertex {
@@ -196,3 +198,8 @@ set_sprite_clip :: proc(sprite: ^Sprite, clip: string) {
 sprite_quad_origin :: proc(position: Vec2, size: Vec2, pivot: [2]f32) -> Vec2 {
 	return {position.x - size.x * pivot[0], position.y - size.y * pivot[1]}
 }
+
+set_sprite_flip_x :: proc(sprite: ^Sprite, flip: bool) {
+	if sprite == nil do return
+	sprite.flip_x = flip
+}

examples/toad/main.odin

@@ -15,12 +15,30 @@ main :: proc() {
 	toad := eng.spawn_sprite(&data, {400, 500}, "idle", 0)
 
 	last := eng.now_seconds()
+	SPEED :: f32(200)
 
 	for eng.events() {
 		now := eng.now_seconds()
 		dt := f32(now - last)
 		last = now
 
+		left := eng.key_down(.A) || eng.key_down(.Left)
+		right := eng.key_down(.D) || eng.key_down(.Right)
+
+		if left || right {
+			eng.set_sprite_clip(&toad, "walk")
+			if left {
+				toad.position.x -= SPEED * dt
+				toad.flip_x = true
+			}
+
+			if right {
+				toad.position.x += SPEED * dt
+				toad.flip_x = false
+			}
+		} else {
+			eng.set_sprite_clip(&toad, "idle")
+		}
 		eng.update_sprite(&toad, dt)
 
 		eng.begin_frame(&app)