render one frame only

examples/toad/main.odin

@@ -1,8 +1,32 @@
 package main
 
+import "core:encoding/json"
 import "core:fmt"
+import "core:os"
+import "core:text/regex/virtual_machine"
 import sdl "vendor:sdl3"
 
+Frame_Def :: struct {
+	rect:        [4]int,
+	source_size: [2]int,
+	trim_offset: [2]int,
+}
+
+Clip_Def :: struct {
+	loop:   bool,
+	fps:    f32,
+	frames: []Frame_Def,
+}
+
+Char_Def :: struct {
+	version:         int,
+	id:              string,
+	atlas:           string,
+	pixels_per_unit: f32,
+	pivot:           [2]f32,
+	clips:           map[string]Clip_Def,
+}
+
 main :: proc() {
 	if !sdl.Init({.VIDEO}) {
 		fmt.eprintfln("SDL_Init failed: %s", sdl.GetError())
@@ -37,6 +61,35 @@ main :: proc() {
 
 	sdl.SetTextureScaleMode(texture, .NEAREST)
 
+	char_path := "assets_baked/characters/toad/toad.char.json"
+	data, read_err := os.read_entire_file(char_path, context.allocator)
+	if read_err != nil {
+		fmt.eprintfln("failed to read %s: %v", char_path, read_err)
+		return
+	}
+	defer delete(data)
+
+	char_def: Char_Def
+	if err := json.unmarshal(data, &char_def); err != nil {
+		fmt.eprintfln("json unmarshal failed: %v", err)
+		return
+	}
+
+	idle, ok := char_def.clips["idle"]
+	if !ok || len(idle.frames) == 0 {
+		fmt.eprintfln("missing idle frames")
+		return
+	}
+
+	// Atlas crop for idle frame 0 — used every frame as `src`
+	r := idle.frames[0].rect // [x, y, w, h]
+	src := sdl.FRect {
+		x = f32(r[0]),
+		y = f32(r[1]),
+		w = f32(r[2]),
+		h = f32(r[3]),
+	}
+
 	running := true
 
 	for running {
@@ -49,13 +102,16 @@ main :: proc() {
 
 		sdl.SetRenderDrawColor(renderer, 30, 30, 40, 255)
 		sdl.RenderClear(renderer)
+
 		dst := sdl.FRect {
-			x = 0,
-			y = 0,
-			w = 400,
-			h = 400,
+			x = 400 - src.w * 0.5,
+			y = 500 - src.h,
+			w = src.w,
+			h = src.h,
 		}
-		sdl.RenderTexture(renderer, texture, nil, &dst)
+
+		sdl.RenderTexture(renderer, texture, &src, &dst)
+
 		sdl.RenderPresent(renderer)
 	}
 }