[feat]: wire in scene into the simulation engine

1 files changed, 25 insertions, 0 deletions

diff --git a/src/rendering/scene_renderer.cpp b/src/rendering/scene_renderer.cpp
index 5ee7657..50b666d 100644
--- a/src/rendering/scene_renderer.cpp
+++ b/src/rendering/scene_renderer.cpp
@@ -42,6 +42,9 @@ namespace Donut
 
         struct SkyboxUBO { glm::mat4 projection; glm::mat4 view; };
         static_assert(sizeof(SkyboxUBO) == 128, "SkyboxUBO std140 layout mismatch");
+
+        // The hole's event horizon (1 r_s) as a marker at the origin.
+        constexpr float BH_SCENE_RADIUS = SCENE_UNITS_PER_RS;
     }
 
     auto SceneRenderer::init(RHI::Device& device) -> bool
@@ -137,6 +140,8 @@ namespace Donut
             m_skybox_pipeline = device.create_pipeline(d);
         }
 
+        m_bh_ubo = device.create_buffer(BufferType::Uniform, sizeof(SphereUBO));
+
         DONUT_INFO("SceneRenderer ready ({} grid verts, {} sphere indices, skybox)",
                    m_grid_vertex_count, m_sphere_index_count);
         return true;
@@ -196,6 +201,26 @@ namespace Donut
                 cmd.bind_index_buffer(m_sphere_ib.get());
                 cmd.draw_indexed(m_sphere_index_count);
             }
+
+            // Black-hole marker: a near-black sphere at the origin (radius = r_s in
+            // scene units), so the Scene shows where the hole the Simulation renders
+            // sits. 1 grid unit == 1 Schwarzschild radius.
+            SphereUBO bh{};
+            bh.view_projection = vp;
+            bh.transform       = glm::scale(glm::mat4(1.0f), glm::vec3(BH_SCENE_RADIUS));
+            bh.color           = glm::vec3(0.02f);            // near-black event horizon
+            bh.specular        = 0.10f;
+            bh.light_pos       = glm::vec3(10.0f, 20.0f, 10.0f);
+            bh.camera_pos      = cam.position;
+            bh.is_selected     = 1;                            // reuse the rim as an
+            bh.outline_color   = glm::vec3(0.98f, 0.62f, 0.20f); // amber accretion glow
+            bh.outline_width   = 0.30f;
+            m_bh_ubo->update(&bh, sizeof(bh));
+            cmd.bind_uniform(0, m_bh_ubo.get());
+            cmd.bind_texture(1, cubemap);
+            cmd.bind_vertex_buffer(m_sphere_vb.get());
+            cmd.bind_index_buffer(m_sphere_ib.get());
+            cmd.draw_indexed(m_sphere_index_count);
         }
 
         // Transparent grid on top (tests depth, doesn't write).