feat(3d): Implement Blender export and binary scene loading pipeline

2 files changed, 122 insertions, 0 deletions

diff --git a/src/3d/scene_loader.cc b/src/3d/scene_loader.cc
new file mode 100644
index 0000000..69079ef
--- /dev/null
+++ b/src/3d/scene_loader.cc
@@ -0,0 +1,108 @@
+#include "3d/scene_loader.h"
+#include "util/asset_manager.h"
+#include "generated/assets.h"
+#include "util/mini_math.h"
+#include <cstring>
+#include <cstdio>
+#include <vector>
+
+bool SceneLoader::LoadScene(Scene& scene, const uint8_t* data, size_t size) {
+    if (!data || size < 16) { // Header size check
+        printf("SceneLoader: Data too small\n");
+        return false;
+    }
+
+    // Check Magic
+    if (std::memcmp(data, "SCN1", 4) != 0) {
+        printf("SceneLoader: Invalid magic (expected SCN1)\n");
+        return false;
+    }
+
+    size_t offset = 4;
+
+    uint32_t num_objects = *reinterpret_cast<const uint32_t*>(data + offset); offset += 4;
+    uint32_t num_cameras = *reinterpret_cast<const uint32_t*>(data + offset); offset += 4;
+    uint32_t num_lights = *reinterpret_cast<const uint32_t*>(data + offset); offset += 4;
+
+    // printf("SceneLoader: Loading %d objects, %d cameras, %d lights\n", num_objects, num_cameras, num_lights);
+
+    for (uint32_t i = 0; i < num_objects; ++i) {
+        if (offset + 64 > size) return false; // Name check
+        
+        char name[65] = {0};
+        std::memcpy(name, data + offset, 64); offset += 64;
+
+        if (offset + 4 > size) return false;
+        uint32_t type_val = *reinterpret_cast<const uint32_t*>(data + offset); offset += 4;
+        ObjectType type = (ObjectType)type_val;
+
+        if (offset + 12 + 16 + 12 + 16 > size) return false; // Transforms + Color
+
+        float px = *reinterpret_cast<const float*>(data + offset); offset += 4;
+        float py = *reinterpret_cast<const float*>(data + offset); offset += 4;
+        float pz = *reinterpret_cast<const float*>(data + offset); offset += 4;
+        vec3 pos(px, py, pz);
+
+        float rx = *reinterpret_cast<const float*>(data + offset); offset += 4;
+        float ry = *reinterpret_cast<const float*>(data + offset); offset += 4;
+        float rz = *reinterpret_cast<const float*>(data + offset); offset += 4;
+        float rw = *reinterpret_cast<const float*>(data + offset); offset += 4;
+        quat rot(rx, ry, rz, rw);
+
+        float sx = *reinterpret_cast<const float*>(data + offset); offset += 4;
+        float sy = *reinterpret_cast<const float*>(data + offset); offset += 4;
+        float sz = *reinterpret_cast<const float*>(data + offset); offset += 4;
+        vec3 scale(sx, sy, sz);
+
+        float cr = *reinterpret_cast<const float*>(data + offset); offset += 4;
+        float cg = *reinterpret_cast<const float*>(data + offset); offset += 4;
+        float cb = *reinterpret_cast<const float*>(data + offset); offset += 4;
+        float ca = *reinterpret_cast<const float*>(data + offset); offset += 4;
+        vec4 color(cr, cg, cb, ca);
+
+        // Mesh Asset Name Length
+        if (offset + 4 > size) return false;
+        uint32_t name_len = *reinterpret_cast<const uint32_t*>(data + offset); offset += 4;
+
+        AssetId mesh_id = (AssetId)0; // Default or INVALID (if 0 is invalid)
+
+        if (name_len > 0) {
+            if (offset + name_len > size) return false;
+            char mesh_name[128] = {0};
+            if (name_len < 128) {
+                std::memcpy(mesh_name, data + offset, name_len);
+            }
+            offset += name_len;
+            
+            // Resolve Asset ID
+            mesh_id = GetAssetIdByName(mesh_name);
+            if (mesh_id == AssetId::ASSET_LAST_ID) {
+                printf("SceneLoader: Warning: Mesh asset '%s' not found for object '%s'\n", mesh_name, name);
+            }
+        }
+
+        // Physics properties
+        if (offset + 4 + 4 + 4 > size) return false;
+        float mass = *reinterpret_cast<const float*>(data + offset); offset += 4;
+        float restitution = *reinterpret_cast<const float*>(data + offset); offset += 4;
+        uint32_t is_static_u32 = *reinterpret_cast<const uint32_t*>(data + offset); offset += 4;
+        bool is_static = (is_static_u32 != 0);
+
+        // Create Object3D
+        Object3D obj(type);
+        obj.position = pos;
+        obj.rotation = rot;
+        obj.scale = scale;
+        obj.color = color;
+        obj.mesh_asset_id = mesh_id;
+        obj.mass = mass;
+        obj.restitution = restitution;
+        obj.is_static = is_static;
+        // user_data is nullptr by default
+
+        // Add to scene
+        scene.add_object(obj);
+    }
+
+    return true;
+}
\ No newline at end of file
diff --git a/src/3d/scene_loader.h b/src/3d/scene_loader.h
new file mode 100644
index 0000000..15f08c7
--- /dev/null
+++ b/src/3d/scene_loader.h
@@ -0,0 +1,14 @@
+#pragma once
+
+#include "3d/scene.h"
+#include <cstdint>
+#include <cstddef>
+
+// SceneLoader handles parsing of binary scene files (.bin) exported from Blender.
+// It populates a Scene object with objects, lights, and cameras.
+class SceneLoader {
+ public:
+  // Loads a scene from a binary buffer.
+  // Returns true on success, false on failure (e.g., invalid magic, version mismatch).
+  static bool LoadScene(Scene& scene, const uint8_t* data, size_t size);
+};