[feat]: implement ui layer arch

3 files changed, 136 insertions, 0 deletions

diff --git a/src/scene/scene.cpp b/src/scene/scene.cpp
new file mode 100644
index 0000000..db70a8d
--- /dev/null
+++ b/src/scene/scene.cpp
@@ -0,0 +1,65 @@
+#include "scene.h"
+
+#include <glm/glm.hpp>
+#include <glm/gtc/matrix_transform.hpp>
+#include <algorithm>
+#include <cmath>
+#include <numbers>
+
+namespace Donut
+{
+    Scene::Scene()
+    {
+        // Black-hole camera: large-scale orbital viewer outside the disk.
+        sim_camera.set_camera_mode(CameraMode::Orbital);
+        sim_camera.set_orbital_target(glm::vec3(0.0f));
+        sim_camera.set_orbital_radius(4e11);          // ~31 r_s: outside the 12 r_s disk
+        sim_camera.set_orbital_limits(2.2e11, 1.5e12);
+        sim_camera.set_orbital_speed(0.01f);
+        sim_camera.set_zoom_speed(3e10);
+        sim_camera.set_azimuth(0.0f);
+        sim_camera.set_elevation(1.25f);
+
+        // Scene camera: normal-scale orbital world-builder viewer.
+        scene_camera.set_camera_mode(CameraMode::Orbital);
+        scene_camera.set_orbital_target(glm::vec3(0.0f));
+        scene_camera.set_orbital_radius(15.0);
+        scene_camera.set_orbital_limits(2.0, 200.0);
+        scene_camera.set_orbital_speed(0.01f);
+        scene_camera.set_zoom_speed(2.0);
+        scene_camera.set_azimuth(0.0f);
+        scene_camera.set_elevation((float)std::numbers::pi / 3.0f);
+        scene_camera.update_orbital();
+    }
+
+    auto Scene::reset_sim_camera() -> void
+    {
+        sim_camera.set_camera_mode(CameraMode::Orbital);
+        sim_camera.set_orbital_radius(4e11);
+        sim_camera.set_azimuth(0.0f);
+        sim_camera.set_elevation(1.25f);
+    }
+
+    auto Scene::set_free_fly(bool enabled) -> void
+    {
+        const bool is_fps = sim_camera.get_camera_mode() == CameraMode::FPS;
+        if (enabled == is_fps) return;
+        if (enabled)
+        {
+            // Seed the fly pose from the current orbital framing so the view is continuous.
+            glm::vec3 pos = sim_camera.get_orbital_position();
+            glm::vec3 fwd = glm::normalize(sim_camera.get_orbital_target() - pos);
+            float pitch = glm::degrees(asin(glm::clamp(fwd.y, -1.0f, 1.0f)));
+            float yaw   = glm::degrees(atan2(fwd.z, fwd.x));
+            sim_camera.set_camera_mode(CameraMode::FPS);
+            sim_camera.set_movement_speed(2.0e10f);
+            sim_camera.set_mouse_sensitivity(0.15f);
+            sim_camera.set_position(pos);
+            sim_camera.set_rotation(glm::vec3(pitch, yaw, 0.0f));
+        }
+        else
+        {
+            sim_camera.set_camera_mode(CameraMode::Orbital);  // orbital state was left intact
+        }
+    }
+}
diff --git a/src/scene/scene.h b/src/scene/scene.h
new file mode 100644
index 0000000..27d1327
--- /dev/null
+++ b/src/scene/scene.h
@@ -0,0 +1,39 @@
+#pragma once
+
+#include "scene_types.h"
+#include "core/camera.h"
+
+#include <string>
+#include <vector>
+
+namespace Donut
+{
+    // The document: everything the app edits and renders, independent of any
+    // backend or UI. Workspaces (tabs) read and mutate this; the RenderPath reads
+    // it to draw. It owns the two viewpoints (cameras) as scene state, plus small
+    // camera-framing helpers, since a viewpoint is part of the document.
+    class Scene
+    {
+    public:
+        Scene();
+
+        // world-builder content
+        std::vector<SceneObject> objects{ SceneObject{} };
+        int selected_object = 0;
+
+        // black hole / accretion disk
+        BlackHoleParams black_hole;
+
+        // environment
+        std::string hdri_path = "assets/hdri/hdr_blue_nebulae_1.hdr";
+
+        // viewpoints
+        Camera sim_camera{ 60.0f, 16.0f / 9.0f, 0.1f, 100.0f };     // black-hole view
+        Camera scene_camera{ 45.0f, 16.0f / 9.0f, 0.1f, 1000.0f };  // world-builder view
+
+        // Camera framing helpers (the sim view supports orbital + free-fly).
+        auto reset_sim_camera() -> void;
+        auto set_free_fly(bool enabled) -> void;
+        auto is_free_fly() const -> bool { return sim_camera.get_camera_mode() == CameraMode::FPS; }
+    };
+}
diff --git a/src/scene/scene_types.h b/src/scene/scene_types.h
new file mode 100644
index 0000000..d34983f
--- /dev/null
+++ b/src/scene/scene_types.h
@@ -0,0 +1,32 @@
+#pragma once
+
+#include <glm/glm.hpp>
+
+namespace Donut
+{
+    // Backend-agnostic scene/black-hole data shared by the Application and the
+    // portable renderers (SceneRenderer, BlackHoleRenderer). The rendering itself
+    // is written once on the RHI (rendering/rhi.h); these are just the inputs.
+
+    // A placeable/editable sphere in the world-builder scene view. The app owns
+    // the list; SceneRenderer draws it the same way on every backend.
+    struct SceneObject
+    {
+        glm::vec3 position = { 0.0f, 2.0f, 0.0f };
+        float     radius   = 2.0f;
+        glm::vec3 color    = { 0.85f, 0.35f, 0.2f };
+    };
+
+    // Live-tunable black-hole / accretion-disk parameters. Radii are in
+    // Schwarzschild radii; the inner edge is clamped to the ISCO (3 r_s).
+    struct BlackHoleParams
+    {
+        float disk_inner_rs = 3.0f;      // inner edge (x r_s)
+        float disk_outer_rs = 12.0f;     // outer edge (x r_s)
+        float temperature   = 4800.0f;   // Kelvin at the flux peak (disk colour)
+        float brightness    = 0.9f;      // disk exposure
+        float turbulence    = 0.4f;      // 0 = smooth physical disk
+        int   quality_steps = 15000;     // geodesic integration steps
+        float fov_degrees   = 60.0f;     // camera field of view
+    };
+}