queue drawing

Movement and sprite flipping

Makefile

@@ -1,7 +1,8 @@
-.PHONY: shaders-vulkan shaders-d3d12 shaders-metal shaders-all toad check test help
+.PHONY: shaders-vulkan shaders-d3d12 shaders-metal shaders-all bake toad check test help
 
 help:
 	@echo "Targets:"
+	@echo "  bake            Bake all characters under content/characters/"
 	@echo "  shaders-vulkan  Compile SPIR-V into shaders/vulkan/"
 	@echo "  shaders-d3d12   Compile DXIL into shaders/d3d12/ (needs shadercross)"
 	@echo "  shaders-metal   Compile MSL into shaders/metal/ (needs shadercross)"
@@ -10,6 +11,9 @@ help:
 	@echo "  check           Typecheck examples/toad"
 	@echo "  toad            Run the toad example"
 
+bake:
+	./scripts/bake_all.sh
+
 shaders-vulkan:
 	./scripts/shaders_vulkan.sh
 

assets_baked/characters/toad/toad.char.json

@@ -10,7 +10,7 @@
     "clips": {
         "walk": {
             "loop": true,
-            "fps": 10.00000000,
+            "fps": 15.00000000,
             "frames": [
                 {
                     "rect": [
@@ -283,80 +283,16 @@
                         0,
                         0
                     ]
-                },
-                {
-                    "rect": [
-                        807,
-                        654,
-                        268,
-                        326
-                    ],
-                    "source_size": [
-                        268,
-                        326
-                    ],
-                    "trim_offset": [
-                        0,
-                        0
-                    ]
                 }
             ]
         },
         "idle": {
             "loop": true,
-            "fps": 10.00000000,
+            "fps": 15.00000000,
             "frames": [
                 {
                     "rect": [
-                        1883,
+                        807,
-                        0,
-                        213,
-                        319
-                    ],
-                    "source_size": [
-                        213,
-                        319
-                    ],
-                    "trim_offset": [
-                        0,
-                        0
-                    ]
-                },
-                {
-                    "rect": [
-                        1883,
-                        320,
-                        213,
-                        319
-                    ],
-                    "source_size": [
-                        213,
-                        319
-                    ],
-                    "trim_offset": [
-                        0,
-                        0
-                    ]
-                },
-                {
-                    "rect": [
-                        1883,
-                        640,
-                        213,
-                        319
-                    ],
-                    "source_size": [
-                        213,
-                        319
-                    ],
-                    "trim_offset": [
-                        0,
-                        0
-                    ]
-                },
-                {
-                    "rect": [
-                        1076,
                         654,
                         213,
                         319
@@ -372,7 +308,7 @@
                 },
                 {
                     "rect": [
-                        1290,
+                        1021,
                         654,
                         213,
                         319
@@ -388,7 +324,7 @@
                 },
                 {
                     "rect": [
-                        1504,
+                        1235,
                         654,
                         213,
                         319
@@ -404,8 +340,8 @@
                 },
                 {
                     "rect": [
-                        1718,
+                        1449,
-                        960,
+                        654,
                         213,
                         319
                     ],
@@ -420,7 +356,23 @@
                 },
                 {
                     "rect": [
-                        1076,
+                        1663,
+                        654,
+                        213,
+                        319
+                    ],
+                    "source_size": [
+                        213,
+                        319
+                    ],
+                    "trim_offset": [
+                        0,
+                        0
+                    ]
+                },
+                {
+                    "rect": [
+                        807,
                         974,
                         213,
                         319
@@ -436,7 +388,7 @@
                 },
                 {
                     "rect": [
-                        1290,
+                        1021,
                         974,
                         213,
                         319
@@ -452,7 +404,39 @@
                 },
                 {
                     "rect": [
-                        1504,
+                        1235,
+                        974,
+                        213,
+                        319
+                    ],
+                    "source_size": [
+                        213,
+                        319
+                    ],
+                    "trim_offset": [
+                        0,
+                        0
+                    ]
+                },
+                {
+                    "rect": [
+                        1449,
+                        974,
+                        213,
+                        319
+                    ],
+                    "source_size": [
+                        213,
+                        319
+                    ],
+                    "trim_offset": [
+                        0,
+                        0
+                    ]
+                },
+                {
+                    "rect": [
+                        1663,
                         974,
                         213,
                         319
@@ -517,7 +501,7 @@
                 {
                     "rect": [
                         642,
-                        981,
+                        1294,
                         213,
                         319
                     ],
@@ -533,23 +517,7 @@
                 {
                     "rect": [
                         856,
-                        981,
+                        1294,
-                        213,
-                        319
-                    ],
-                    "source_size": [
-                        213,
-                        319
-                    ],
-                    "trim_offset": [
-                        0,
-                        0
-                    ]
-                },
-                {
-                    "rect": [
-                        1718,
-                        1280,
                         213,
                         319
                     ],
@@ -593,6 +561,22 @@
                         0,
                         0
                     ]
+                },
+                {
+                    "rect": [
+                        1498,
+                        1294,
+                        213,
+                        319
+                    ],
+                    "source_size": [
+                        213,
+                        319
+                    ],
+                    "trim_offset": [
+                        0,
+                        0
+                    ]
                 }
             ]
         }

content/characters/toad/manifest.json

@@ -5,12 +5,12 @@
   "clips": {
     "idle": {
       "folder": "Idle",
-      "fps": 10,
+      "fps": 15,
       "loop": true
     },
     "walk": {
       "folder": "Walk",
-      "fps": 10,
+      "fps": 15,
       "loop": true
     }
   }

engine/animation_test.odin

@@ -0,0 +1,232 @@
+package engine
+
+import "core:testing"
+
+make_test_character :: proc(allocator := context.allocator) -> Character_Data {
+	data: Character_Data
+	data.def.clips = make(map[string]Clip_Def, allocator)
+
+	idle_frames := make([]Frame_Def, 3, allocator)
+	idle_frames[0] = {
+		rect = {0, 0, 10, 10},
+	}
+	idle_frames[1] = {
+		rect = {10, 0, 10, 10},
+	}
+	idle_frames[2] = {
+		rect = {20, 0, 10, 10},
+	}
+	data.def.clips["idle"] = Clip_Def {
+		loop   = true,
+		fps    = 10,
+		frames = idle_frames,
+	}
+
+	once_frames := make([]Frame_Def, 3, allocator)
+	once_frames[0] = {
+		rect = {0, 10, 10, 10},
+	}
+	once_frames[1] = {
+		rect = {10, 10, 10, 10},
+	}
+	once_frames[2] = {
+		rect = {20, 10, 10, 10},
+	}
+	data.def.clips["once"] = Clip_Def {
+		loop   = false,
+		fps    = 10,
+		frames = once_frames,
+	}
+
+	hold_frames := make([]Frame_Def, 2, allocator)
+	hold_frames[0] = {
+		rect = {0, 20, 10, 10},
+	}
+	hold_frames[1] = {
+		rect = {10, 20, 10, 10},
+	}
+	data.def.clips["hold"] = Clip_Def {
+		loop   = true,
+		fps    = 0,
+		frames = hold_frames,
+	}
+
+	return data
+}
+
+destroy_test_character :: proc(data: ^Character_Data) {
+	if data == nil do return
+	keys := make([dynamic]string, context.temp_allocator)
+	for key, clip in data.def.clips {
+		delete(clip.frames)
+		append(&keys, key)
+	}
+	for key in keys {
+		delete_key(&data.def.clips, key)
+	}
+	delete(data.def.clips)
+	data^ = {}
+}
+
+@(test)
+character_clip_found_and_missing :: proc(t: ^testing.T) {
+	data := make_test_character()
+	defer destroy_test_character(&data)
+
+	clip, ok := character_clip(&data, "idle")
+	testing.expect(t, ok)
+	testing.expect_value(t, len(clip.frames), 3)
+	testing.expect(t, clip.loop)
+	testing.expect_value(t, clip.fps, f32(10))
+
+	_, ok = character_clip(&data, "missing")
+	testing.expect(t, !ok)
+
+	data.def.clips["empty"] = Clip_Def {
+		loop   = true,
+		fps    = 10,
+		frames = nil,
+	}
+	_, ok = character_clip(&data, "empty")
+	testing.expect(t, !ok)
+}
+
+@(test)
+set_sprite_clip_switch_and_guards :: proc(t: ^testing.T) {
+	data := make_test_character()
+	defer destroy_test_character(&data)
+
+	sprite := spawn_sprite(&data, {0, 0}, "idle", 0)
+	testing.expect_value(t, sprite.clip, "idle")
+
+	sprite.frame = 2
+	sprite.time = 0.05
+	set_sprite_clip(&sprite, "once")
+	testing.expect_value(t, sprite.clip, "once")
+	testing.expect_value(t, sprite.frame, 0)
+	testing.expect_value(t, sprite.time, f32(0))
+
+	sprite.frame = 1
+	sprite.time = 0.09
+	set_sprite_clip(&sprite, "once")
+	testing.expect_value(t, sprite.frame, 1)
+	testing.expect_value(t, sprite.time, f32(0.09))
+
+	set_sprite_clip(&sprite, "nope")
+	testing.expect_value(t, sprite.clip, "once")
+	testing.expect_value(t, sprite.frame, 1)
+	testing.expect_value(t, sprite.time, f32(0.09))
+}
+
+@(test)
+spawn_sprite_valid_and_invalid :: proc(t: ^testing.T) {
+	data := make_test_character()
+	defer destroy_test_character(&data)
+
+	s := spawn_sprite(&data, {1, 2}, "idle", 0)
+	testing.expect_value(t, s.clip, "idle")
+	testing.expect_value(t, s.frame, 0)
+	testing.expect_value(t, s.time, f32(0))
+	testing.expect_value(t, s.position, Vec2{1, 2})
+
+	s2 := spawn_sprite(&data, {}, "idle", 2)
+	testing.expect_value(t, s2.clip, "idle")
+	testing.expect_value(t, s2.frame, 2)
+
+	s3 := spawn_sprite(&data, {}, "idle", 99)
+	testing.expect_value(t, s3.frame, 2)
+
+	bad := spawn_sprite(&data, {}, "missing", 0)
+	testing.expect_value(t, bad.clip, "")
+	testing.expect_value(t, bad.frame, 0)
+	testing.expect_value(t, bad.time, f32(0))
+}
+
+@(test)
+update_sprite_advances_one_frame :: proc(t: ^testing.T) {
+	data := make_test_character()
+	defer destroy_test_character(&data)
+
+	s := spawn_sprite(&data, {}, "idle", 0)
+	update_sprite(&s, 0.1)
+	testing.expect_value(t, s.frame, 1)
+	testing.expect_value(t, s.time, f32(0))
+}
+
+@(test)
+update_sprite_advances_multiple_frames :: proc(t: ^testing.T) {
+	data := make_test_character()
+	defer destroy_test_character(&data)
+
+	s := spawn_sprite(&data, {}, "idle", 0)
+	update_sprite(&s, 0.25)
+	testing.expect_value(t, s.frame, 2)
+	testing.expect(t, s.time > 0.049 && s.time < 0.051)
+}
+
+@(test)
+update_sprite_loops :: proc(t: ^testing.T) {
+	data := make_test_character()
+	defer destroy_test_character(&data)
+
+	s := spawn_sprite(&data, {}, "idle", 2)
+	update_sprite(&s, 0.1)
+	testing.expect_value(t, s.frame, 0)
+}
+
+@(test)
+update_sprite_non_loop_holds_last :: proc(t: ^testing.T) {
+	data := make_test_character()
+	defer destroy_test_character(&data)
+
+	s := spawn_sprite(&data, {}, "once", 2)
+	s.time = 0.05
+	update_sprite(&s, 0.1)
+	testing.expect_value(t, s.frame, 2)
+	testing.expect_value(t, s.time, f32(0))
+}
+
+@(test)
+update_sprite_fps_zero_holds :: proc(t: ^testing.T) {
+	data := make_test_character()
+	defer destroy_test_character(&data)
+
+	s := spawn_sprite(&data, {}, "hold", 0)
+	update_sprite(&s, 1.0)
+	testing.expect_value(t, s.frame, 0)
+}
+
+@(test)
+update_sprite_dt_non_positive_noop :: proc(t: ^testing.T) {
+	data := make_test_character()
+	defer destroy_test_character(&data)
+
+	s := spawn_sprite(&data, {}, "idle", 0)
+	update_sprite(&s, 0)
+	update_sprite(&s, -0.1)
+	testing.expect_value(t, s.frame, 0)
+	testing.expect_value(t, s.time, f32(0))
+}
+
+@(test)
+update_sprite_nil_and_missing_clip_safe :: proc(t: ^testing.T) {
+	update_sprite(nil, 0.1)
+
+	data := make_test_character()
+	defer destroy_test_character(&data)
+
+	s := Sprite {
+		data  = &data,
+		clip  = "missing",
+		frame = 0,
+		time  = 0,
+	}
+	update_sprite(&s, 0.1)
+	testing.expect_value(t, s.frame, 0)
+
+	s2 := Sprite {
+		data = nil,
+		clip = "idle",
+	}
+	update_sprite(&s2, 0.1)
+}

engine/app.odin

@@ -1,6 +1,7 @@
 package engine
 
 import "core:fmt"
+import "core:mem"
 import "core:path/filepath"
 import sdl "vendor:sdl3"
 
@@ -10,7 +11,14 @@ Vertex :: struct {
 }
 
 SPRITE_VERT_COUNT :: 6
-VERTEX_BUFFER_SIZE :: SPRITE_VERT_COUNT * size_of(Vertex)
+MAX_SPRITES :: 128
+SPRITE_VERTS_SIZE :: SPRITE_VERT_COUNT * size_of(Vertex)
+VERTEX_BUFFER_SIZE :: MAX_SPRITES * SPRITE_VERTS_SIZE
+
+Queued_Sprite :: struct {
+	texture: ^sdl.GPUTexture,
+	verts:   [SPRITE_VERT_COUNT]Vertex,
+}
 
 App :: struct {
 	window:            ^sdl.Window,
@@ -25,6 +33,8 @@ App :: struct {
 	swapchain_h:       u32,
 	vertex_buffer:     ^sdl.GPUBuffer,
 	transfer_buffer:   ^sdl.GPUTransferBuffer,
+	draw_list:         [dynamic]Queued_Sprite,
+	clear_color:       sdl.FColor,
 }
 
 Shader_Backend :: enum {
@@ -112,10 +122,14 @@ init :: proc(app: ^App, title: cstring, width, height: i32) -> bool {
 		return false
 	}
 
+	app.draw_list = make([dynamic]Queued_Sprite)
+
 	return true
 }
 
 shutdown :: proc(app: ^App) {
+	delete(app.draw_list)
+
 	if app.device != nil {
 		ok := sdl.WaitForGPUIdle(app.device)
 		if !ok {
@@ -164,9 +178,13 @@ events :: proc() -> bool {
 	return true
 }
 
-begin_frame :: proc(app: ^App, clear: sdl.FColor = {0.12, 0.12, 0.16, 1}) {
+begin_frame :: proc(app: ^App, clear_color: sdl.FColor = {0.12, 0.12, 0.16, 1}) {
-	app.cmd = sdl.AcquireGPUCommandBuffer(app.device)
+	clear(&app.draw_list)
+	app.clear_color = clear_color
+	app.render_pass = nil
+	app.swapchain_texture = nil
 
+	app.cmd = sdl.AcquireGPUCommandBuffer(app.device)
 	if app.cmd == nil {
 		fmt.eprintfln("AcquireGPUCommandBuffer failed: %s", sdl.GetError())
 		return
@@ -181,36 +199,98 @@ begin_frame :: proc(app: ^App, clear: sdl.FColor = {0.12, 0.12, 0.16, 1}) {
 	)
 
 	if !ok || app.swapchain_texture == nil {
+		app.swapchain_texture = nil
 		return
 	}
+}
+
+end_frame :: proc(app: ^App) {
+	if app.cmd == nil {
+		clear(&app.draw_list)
+		return
+	}
+
+	cmd := app.cmd
+	defer {
+		app.render_pass = nil
+		app.swapchain_texture = nil
+		app.cmd = nil
+		clear(&app.draw_list)
+	}
+
+	if app.swapchain_texture == nil {
+		if !sdl.SubmitGPUCommandBuffer(cmd) {
+			fmt.eprintfln("SubmitGPUCommandBuffer failed")
+		}
+		return
+	}
+
+	n := len(app.draw_list)
+	if n > 0 {
+		map_ptr := sdl.MapGPUTransferBuffer(app.device, app.transfer_buffer, false)
+		if map_ptr == nil {
+			fmt.eprintfln("MapGPUTransferBuffer failed: %s", sdl.GetError())
+			if !sdl.SubmitGPUCommandBuffer(cmd) {
+				fmt.eprintfln("SubmitGPUCommandBuffer failed")
+			}
+			return
+		}
+
+		for i in 0 ..< n {
+			q := &app.draw_list[i]
+			offset := i * SPRITE_VERTS_SIZE
+			mem.copy(
+				rawptr(uintptr(map_ptr) + uintptr(offset)),
+				raw_data(q.verts[:]),
+				SPRITE_VERTS_SIZE,
+			)
+		}
+		sdl.UnmapGPUTransferBuffer(app.device, app.transfer_buffer)
+
+		copy_pass := sdl.BeginGPUCopyPass(cmd)
+		src := sdl.GPUTransferBufferLocation {
+			transfer_buffer = app.transfer_buffer,
+			offset          = 0,
+		}
+		dst := sdl.GPUBufferRegion {
+			buffer = app.vertex_buffer,
+			offset = 0,
+			size   = u32(n * SPRITE_VERTS_SIZE),
+		}
+		sdl.UploadToGPUBuffer(copy_pass, src, dst, false)
+		sdl.EndGPUCopyPass(copy_pass)
+	}
 
 	color_info := sdl.GPUColorTargetInfo {
 		texture     = app.swapchain_texture,
-		clear_color = clear,
+		clear_color = app.clear_color,
 		load_op     = .CLEAR,
 		store_op    = .STORE,
 	}
-
+	app.render_pass = sdl.BeginGPURenderPass(cmd, &color_info, 1, nil)
-	app.render_pass = sdl.BeginGPURenderPass(app.cmd, &color_info, 1, nil)
-
 	sdl.BindGPUGraphicsPipeline(app.render_pass, app.pipeline)
-}
 
-end_frame :: proc(app: ^App) {
+	for q, i in app.draw_list {
-	if app.render_pass != nil {
+		sampler_binding := sdl.GPUTextureSamplerBinding {
-		sdl.EndGPURenderPass(app.render_pass)
+			texture = q.texture,
-		app.render_pass = nil
+			sampler = app.sampler,
-	}
-
-	if app.cmd != nil {
-		ok := sdl.SubmitGPUCommandBuffer(app.cmd)
-		if !ok {
-			fmt.eprintfln("SubmitGPUCommandBuffer failed")
 		}
-		app.cmd = nil
+		sdl.BindGPUFragmentSamplers(app.render_pass, 0, &sampler_binding, 1)
+
+		vb_binding := sdl.GPUBufferBinding {
+			buffer = app.vertex_buffer,
+			offset = u32(i * SPRITE_VERTS_SIZE),
+		}
+		sdl.BindGPUVertexBuffers(app.render_pass, 0, &vb_binding, 1)
+		sdl.DrawGPUPrimitives(app.render_pass, SPRITE_VERT_COUNT, 1, 0, 0)
 	}
 
-	app.swapchain_texture = nil
+	sdl.EndGPURenderPass(app.render_pass)
+	app.render_pass = nil
+
+	if !sdl.SubmitGPUCommandBuffer(cmd) {
+		fmt.eprintfln("SubmitGPUCommandBuffer failed")
+	}
 }
 
 load_gpu_shader :: proc(

engine/character_data.odin

@@ -170,7 +170,10 @@ load_character_data :: proc(app: ^App, character_json_path: string) -> (Characte
 	sdl.EndGPUCopyPass(copy_pass)
 	fence := sdl.SubmitGPUCommandBufferAndAcquireFence(cmd)
 	if fence == nil {
-		fmt.eprintfln("SubmitGPUCommandBufferAndAcquireFence (texture upload) failed: %s", sdl.GetError())
+		fmt.eprintfln(
+			"SubmitGPUCommandBufferAndAcquireFence (texture upload) failed: %s",
+			sdl.GetError(),
+		)
 		sdl.ReleaseGPUTransferBuffer(app.device, tbuf)
 		sdl.ReleaseGPUTexture(app.device, out.texture)
 		return {}, false
@@ -200,6 +203,13 @@ destroy_character_data :: proc(app: ^App, data: ^Character_Data) {
 	data^ = {}
 }
 
+character_clip :: proc(data: ^Character_Data, clip_name: string) -> (clip: Clip_Def, ok: bool) {
+	if data == nil do return {}, false
+	character, found := data.def.clips[clip_name]
+	if !found || len(character.frames) == 0 do return {}, false
+	return character, true
+}
+
 character_frame_rect :: proc(
 	data: ^Character_Data,
 	clip_name: string,

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

@@ -1,6 +1,5 @@
 package engine
 
-import "core:mem"
 import sdl "vendor:sdl3"
 
 Vec2 :: [2]f32
@@ -10,6 +9,8 @@ Sprite :: struct {
 	position: Vec2,
 	clip:     string,
 	frame:    int,
+	time:     f32,
+	flip_x:   bool,
 }
 
 spawn_sprite :: proc(
@@ -18,13 +19,60 @@ spawn_sprite :: proc(
 	clip: string = "idle",
 	frame: int = 0,
 ) -> Sprite {
-	return Sprite{data = data, position = position, clip = clip, frame = frame}
+	sprite := Sprite {
+		data     = data,
+		position = position,
+	}
+	set_sprite_clip(&sprite, clip)
+	if frame != 0 {
+		c, ok := character_clip(sprite.data, sprite.clip)
+		if ok {
+			if frame < 0 {
+				sprite.frame = 0
+			} else if frame >= len(c.frames) {
+				sprite.frame = len(c.frames) - 1
+			} else {
+				sprite.frame = frame
+			}
+		}
+	}
+	return sprite
 }
 
-// stubbed for later
 update_sprite :: proc(sprite: ^Sprite, dt: f32) {
-	_ = sprite
+	if sprite == nil || sprite.data == nil do return
-	_ = dt
+	if dt <= 0 do return
+
+	clip, ok := character_clip(sprite.data, sprite.clip)
+	if !ok do return
+
+	frame_count := len(clip.frames)
+	if frame_count <= 0 do return
+
+	if sprite.frame < 0 do sprite.frame = 0
+	if sprite.frame >= frame_count do sprite.frame = frame_count - 1
+
+	if clip.fps <= 0 do return
+
+	sprite.time += dt
+	frame_duration := 1.0 / clip.fps
+
+	for sprite.time >= frame_duration {
+		sprite.time -= frame_duration
+		next := sprite.frame + 1
+
+		if next >= frame_count {
+			if clip.loop {
+				sprite.frame = 0
+			} else {
+				sprite.frame = frame_count - 1
+				sprite.time = 0
+				break
+			}
+		} else {
+			sprite.frame = next
+		}
+	}
 }
 
 to_clip :: proc(px, py, sw, sh: f32) -> [2]f32 {
@@ -35,12 +83,15 @@ to_clip :: proc(px, py, sw, sh: f32) -> [2]f32 {
 }
 
 draw_sprite :: proc(app: ^App, sprite: ^Sprite) {
-	if app.render_pass == nil || app.cmd == nil || app.swapchain_texture == nil {
+	if app.cmd == nil || app.swapchain_texture == nil {
 		return // begin_frame may have skipped (minimized window, etc.)
 	}
 	if sprite == nil || sprite.data == nil || sprite.data.texture == nil {
 		return
 	}
+	if len(app.draw_list) >= MAX_SPRITES {
+		return
+	}
 
 	rect, ok := character_frame_rect(sprite.data, sprite.clip, sprite.frame)
 	if !ok {
@@ -50,9 +101,10 @@ draw_sprite :: proc(app: ^App, sprite: ^Sprite) {
 	fw := f32(rect[2])
 	fh := f32(rect[3])
 
-	// Feet-centered placement, same as renderer version
+	pivot := sprite.data.def.pivot
-	x0_px := sprite.position.x - fw * 0.5
+	origin := sprite_quad_origin(sprite.position, {fw, fh}, pivot)
-	y0_px := sprite.position.y - fh
+	x0_px := origin.x
+	y0_px := origin.y
 	x1_px := x0_px + fw
 	y1_px := y0_px + fh
 
@@ -69,9 +121,10 @@ 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 {
+	verts := [SPRITE_VERT_COUNT]Vertex {
 		{pos = p0, uv = {u0, v0}},
 		{pos = p1, uv = {u1, v0}},
 		{pos = p2, uv = {u1, v1}},
@@ -80,52 +133,30 @@ draw_sprite :: proc(app: ^App, sprite: ^Sprite) {
 		{pos = p3, uv = {u0, v1}},
 	}
 
-	map_ptr := sdl.MapGPUTransferBuffer(app.device, app.transfer_buffer, false)
+	append(
-	if map_ptr == nil {
+		&app.draw_list,
-		return
+		Queued_Sprite{texture = sprite.data.texture, verts = verts},
-	}
+	)
-	mem.copy(map_ptr, raw_data(verts[:]), size_of(verts))
+}
-	sdl.UnmapGPUTransferBuffer(app.device, app.transfer_buffer)
+
-
+set_sprite_clip :: proc(sprite: ^Sprite, clip: string) {
-	// IMPORTANT: SDL does not allow beginning a copy pass while a render pass
+	if sprite == nil || sprite.data == nil do return
-	// is active on the same command buffer. Upload on a separate command buffer.
+
-	copy_cmd := sdl.AcquireGPUCommandBuffer(app.device)
+	if sprite.clip == clip do return
-	if copy_cmd == nil {
+
-		return
+	_, ok := character_clip(sprite.data, clip)
-	}
+	if !ok do return
-	copy_pass := sdl.BeginGPUCopyPass(copy_cmd)
+
-
+	sprite.clip = clip
-	src := sdl.GPUTransferBufferLocation {
+	sprite.frame = 0
-		transfer_buffer = app.transfer_buffer,
+	sprite.time = 0
-		offset          = 0,
+}
-	}
+
-	dst := sdl.GPUBufferRegion {
+sprite_quad_origin :: proc(position: Vec2, size: Vec2, pivot: [2]f32) -> Vec2 {
-		buffer = app.vertex_buffer,
+	return {position.x - size.x * pivot[0], position.y - size.y * pivot[1]}
-		offset = 0,
+}
-		size   = u32(size_of(verts)),
+
-	}
+set_sprite_flip_x :: proc(sprite: ^Sprite, flip: bool) {
-	sdl.UploadToGPUBuffer(copy_pass, src, dst, false)
+	if sprite == nil do return
-	sdl.EndGPUCopyPass(copy_pass)
+	sprite.flip_x = flip
-	fence := sdl.SubmitGPUCommandBufferAndAcquireFence(copy_cmd)
-	if fence == nil {
-		return
-	}
-	defer sdl.ReleaseGPUFence(app.device, fence)
-	if !sdl.WaitForGPUFences(app.device, true, &fence, 1) {
-		return
-	}
-
-	sampler_binding := sdl.GPUTextureSamplerBinding {
-		texture = sprite.data.texture,
-		sampler = app.sampler,
-	}
-	sdl.BindGPUFragmentSamplers(app.render_pass, 0, &sampler_binding, 1)
-
-	vb_binding := sdl.GPUBufferBinding {
-		buffer = app.vertex_buffer,
-		offset = 0,
-	}
-	sdl.BindGPUVertexBuffers(app.render_pass, 0, &vb_binding, 1)
-
-	sdl.DrawGPUPrimitives(app.render_pass, 6, 1, 0, 0)
 }

engine/sprite_test.odin

@@ -19,3 +19,17 @@ to_clip_corners :: proc(t: ^testing.T) {
 	testing.expect_value(t, p[0], f32(0))
 	testing.expect_value(t, p[1], f32(0))
 }
+
+@(test)
+sprite_quad_origin_feet :: proc(t: ^testing.T) {
+	o := sprite_quad_origin({400, 500}, {100, 200}, {0.5, 1.0})
+	testing.expect_value(t, o.x, f32(350))
+	testing.expect_value(t, o.y, f32(300))
+}
+
+@(test)
+sprite_quad_origin_center :: proc(t: ^testing.T) {
+	o := sprite_quad_origin({400, 500}, {100, 200}, {0.5, 0.5})
+	testing.expect_value(t, o.x, f32(350))
+	testing.expect_value(t, o.y, f32(400))
+}

engine/time.odin

@@ -0,0 +1,8 @@
+package engine
+
+import sdl "vendor:sdl3"
+
+// now_seconds returns seconds since SDL init (monotonic for frame timing).
+now_seconds :: proc() -> f64 {
+	return f64(sdl.GetTicksNS()) / 1_000_000_000.0
+}

examples/toad/main.odin

@@ -4,7 +4,7 @@ import eng "pkg:engine"
 
 main :: proc() {
 	app: eng.App
-	if !eng.init(&app, "toad", 800, 600) do return
+	if !eng.init(&app, "toad game", 800, 600) do return
 	defer eng.shutdown(&app)
 
 	data, ok := eng.load_character_data(&app, "assets_baked/characters/toad/toad.char.json")
@@ -14,10 +14,35 @@ 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)
 		eng.draw_sprite(&app, &toad)
 		eng.end_frame(&app)
 	}
 }
-

scripts/bake_all.sh

@@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+cd "$ROOT"
+
+CONTENT_ROOT="${CONTENT_ROOT:-content/characters}"
+OUT_ROOT="${OUT_ROOT:-assets_baked/characters}"
+
+if [[ ! -d "$CONTENT_ROOT" ]]; then
+	echo "missing content root: $CONTENT_ROOT" >&2
+	exit 1
+fi
+
+shopt -s nullglob
+manifests=("$CONTENT_ROOT"/*/manifest.json)
+if [[ ${#manifests[@]} -eq 0 ]]; then
+	echo "no character manifests under $CONTENT_ROOT" >&2
+	exit 1
+fi
+
+for manifest in "${manifests[@]}"; do
+	char_dir="$(dirname "$manifest")"
+	name="$(basename "$char_dir")"
+	out_dir="$OUT_ROOT/$name"
+	mkdir -p "$out_dir"
+	echo "baking $name -> $out_dir"
+	odin run assetbake -- "$char_dir" "$out_dir"
+done
+
+echo "baked ${#manifests[@]} character(s)"