feat: finish most world builder features

2 files changed, 105 insertions, 13 deletions

diff --git a/src/states/world_builder_state.cpp b/src/states/world_builder_state.cpp
index 1067d41..a01935c 100644
--- a/src/states/world_builder_state.cpp
+++ b/src/states/world_builder_state.cpp
@@ -45,6 +45,10 @@ namespace Donut
         m_sphere_shader = Ref<Shader>(Shader::create("assets/shaders/sphere.glsl"));
         initialize_sphere_geometry();
         
+        Material black_hole_material(glm::vec3(0.0f, 0.0f, 0.0f), 0.0f, 0.0f);
+        m_black_hole = Object(glm::vec3(0.0f, 0.0f, 0.0f), 2.0f, black_hole_material);
+        m_black_hole_initialized = true;
+        
         m_initialized = true;
     }
     
@@ -84,7 +88,7 @@ namespace Donut
     
     void WorldBuilderState::on_render()
     {
-        RenderCommand::set_clear_color(glm::vec4(0.05f, 0.05f, 0.05f, 1.0f));
+        RenderCommand::set_clear_color(glm::vec4(0.1f, 0.1f, 0.1f, 1.0f));
         RenderCommand::clear();
         render_scene();
     }
@@ -127,6 +131,32 @@ namespace Donut
                 float closest_distance  = std::numeric_limits<float>::max();
                 int closest_object_index = -1;
                 
+                if (m_black_hole_initialized)
+                {
+                    glm::vec3 oc       = ray_origin - m_black_hole.m_centre;
+                    float a            = glm::dot(ray_dir, ray_dir);
+                    float b            = 2.0f * glm::dot(oc, ray_dir);
+                    float c            = glm::dot(oc, oc) - m_black_hole.m_radius * m_black_hole.m_radius;
+                    float discriminant = b * b - 4 * a * c;
+                    
+                    if (discriminant > 0)
+                    {
+                        float t1 = (-b - sqrt(discriminant)) / (2.0f * a);
+                        float t2 = (-b + sqrt(discriminant)) / (2.0f * a);
+                        
+                        if (t1 > 0 && t1 < closest_distance)
+                        {
+                            closest_distance = t1;
+                            closest_object_index = -2;
+                        }
+                        else if (t2 > 0 && t2 < closest_distance)
+                        {
+                            closest_distance = t2;
+                            closest_object_index = -2;
+                        }
+                    }
+                }
+                
                 for (size_t i = 0; i < m_scene.objs.size(); ++i)
                 {
                     const Object& obj = m_scene.objs[i];
@@ -161,6 +191,12 @@ namespace Donut
                     DONUT_INFO("Selected object {}", closest_object_index);
                     return true;
                 }
+                else if (closest_object_index == -2)
+                {
+                    m_selected_object_index = -1;
+                    DONUT_INFO("Black hole clicked (not selectable)");
+                    return true;
+                }
                 else
                 {
                     m_selected_object_index = -1;
@@ -256,9 +292,9 @@ namespace Donut
         ImGui::PopFont();
         ImGui::Separator();
         
-         if (ImGui::CollapsingHeader("Scene Info", &m_show_scene_info))
+                 if (ImGui::CollapsingHeader("Scene Info", &m_show_scene_info))
          {
-            ImGui::Text("Objects in scene: %zu", m_scene.objs.size());
+            ImGui::Text("Objects in scene: %zu/16 (+ 1 black hole)", m_scene.objs.size());
             
             ImGui::Separator();
             ImGui::TextColored(ImVec4(0.9f, 0.9f, 1.0f, 1.0f), "Camera Info:");
@@ -309,6 +345,8 @@ namespace Donut
             ImGui::TextColored(ImVec4(0.9f, 0.9f, 1.0f, 1.0f), "New Sphere");
             ImGui::Separator();
             
+            ImGui::TextColored(ImVec4(0.8f, 0.8f, 0.8f, 1.0f), "Objects: %zu/16", m_scene.objs.size());
+            
             ImGui::Text("Position:");
             ImGui::DragFloat3("##Position", &m_new_object_position.x, 0.1f);
             
@@ -326,16 +364,39 @@ namespace Donut
             
             ImGui::Spacing();
             
-            if (ImGui::Button("Add Sphere", ImVec2(ImGui::GetWindowWidth() - 20, 30)))
-                add_sphere();
+            if (m_scene.objs.size() >= 16)
+            {
+                ImGui::PushStyleVar(ImGuiStyleVar_Alpha, 0.5f);
+                ImGui::Button("Add Sphere (Limit Reached)", ImVec2(ImGui::GetWindowWidth() - 20, 30));
+                ImGui::PopStyleVar();
+            }
+            else
+            {
+                if (ImGui::Button("Add Sphere", ImVec2(ImGui::GetWindowWidth() - 20, 30)))
+                    add_sphere();
+            }
         }
         
         ImGui::Spacing();
         
         if (ImGui::CollapsingHeader("Scene Objects", &m_show_object_list))
         {
+            if (m_black_hole_initialized)
+            {
+                ImGui::PushID(-1);
+                
+                ImGui::TextColored(ImVec4(1.0f, 1.0f, 1.0f, 1.0f), "Black Hole (Center)");
+                ImGui::TextColored(ImVec4(0.7f, 0.7f, 0.7f, 1.0f), "Position: (0.00, 0.00, 0.00)");
+                ImGui::TextColored(ImVec4(0.7f, 0.7f, 0.7f, 1.0f), "Radius: %.2f", m_black_hole.m_radius);
+                ImGui::TextColored(ImVec4(0.7f, 0.7f, 0.7f, 1.0f), "Color: Black (with white outline)");
+                ImGui::TextColored(ImVec4(0.5f, 0.5f, 0.5f, 1.0f), "Cannot be removed or modified");
+                
+                ImGui::PopID();
+                ImGui::Separator();
+            }
+            
             if (m_scene.objs.empty())
-                ImGui::TextColored(ImVec4(0.7f, 0.7f, 0.7f, 1.0f), "No objects in scene");
+                ImGui::TextColored(ImVec4(0.7f, 0.7f, 0.7f, 1.0f), "No additional objects in scene");
             else
             {
                 for (size_t i = 0; i < m_scene.objs.size(); ++i)
@@ -430,7 +491,8 @@ namespace Donut
         ImGui::End();
         
         if (m_selected_object_index >= 0 && 
-            m_selected_object_index < static_cast<int>(m_scene.objs.size()))
+            m_selected_object_index < static_cast<int>(m_scene.objs.size()) &&
+            m_selected_object_index != -2)
         {
             glm::mat4 view       = m_camera.get_view_matrix();
             glm::mat4 projection = m_camera.get_projection_matrix();
@@ -457,7 +519,8 @@ namespace Donut
                 glm::vec3 new_position = glm::vec3(object_transform[3][0], object_transform[3][1], object_transform[3][2]);
                 selected_obj.m_centre = new_position;
                 
-                glm::vec3 scale = glm::vec3(
+                glm::vec3 scale = glm::vec3
+                (
                     glm::length(glm::vec3(object_transform[0])),
                     glm::length(glm::vec3(object_transform[1])),
                     glm::length(glm::vec3(object_transform[2]))
@@ -468,21 +531,29 @@ namespace Donut
                 DONUT_INFO("New position: ({}, {}, {})", new_position.x, new_position.y, new_position.z);
             }
         }
-     }
+    }
     
     void WorldBuilderState::add_sphere()
     {
+        if (m_scene.objs.size() >= 16)
+        {
+            DONUT_WARN("Cannot add more objects. Maximum of 16 objects reached.");
+            return;
+        }
+        
         Material material(m_new_object_color, m_new_object_specular, m_new_object_emission);
         Object   sphere(m_new_object_position, m_new_object_radius, material);
         m_scene.objs.push_back(sphere);
         
+        m_selected_object_index = static_cast<int>(m_scene.objs.size() - 1);
+        
         m_new_object_position = glm::vec3(0.0f, 0.0f, 0.0f);
         m_new_object_radius   = 1.0f;
         m_new_object_color    = glm::vec3(1.0f, 1.0f, 1.0f);
         m_new_object_specular = 0.5f;
         m_new_object_emission = 0.0f;
         
-        DONUT_INFO("Added sphere to scene");
+        DONUT_INFO("Added sphere to scene and selected it");
     }
     
     void WorldBuilderState::remove_selected_object()
@@ -499,7 +570,7 @@ namespace Donut
     {
         m_scene.objs.clear();
         m_selected_object_index = -1;
-        DONUT_INFO("Cleared scene");
+        DONUT_INFO("Cleared scene (black hole remains at center)");
     }
     
     void WorldBuilderState::save_scene()
@@ -535,7 +606,7 @@ namespace Donut
         {
             file << scene_data.dump(4);
             file.close();
-            DONUT_INFO("Scene saved to Scene.json");
+            DONUT_INFO("Scene saved to Scene.json (black hole always present at center)");
         }
         else
             DONUT_ERROR("Failed to save scene");
@@ -583,7 +654,7 @@ namespace Donut
             }
             
             file.close();
-            DONUT_INFO("Scene loaded from Scene.json");
+            DONUT_INFO("Scene loaded from Scene.json (black hole remains at center)");
         }
         else
             DONUT_ERROR("Failed to load scene");
@@ -680,6 +751,24 @@ namespace Donut
         m_sphere_shader->set_float3("u_OutlineColor", m_outline_color);
         m_sphere_shader->set_float("u_OutlineWidth",  m_outline_width);
         
+        if (m_black_hole_initialized)
+        {
+            glm::mat4 black_hole_transform = glm::translate(glm::mat4(1.0f), m_black_hole.m_centre);
+                      black_hole_transform = glm::scale(black_hole_transform, glm::vec3(m_black_hole.m_radius));
+            
+            m_sphere_shader->set_mat4("u_Transform", black_hole_transform);
+            m_sphere_shader->set_int("u_IsSelected", 1);
+            m_sphere_shader->set_float3("u_Color", m_black_hole.m_material.m_color);
+            m_sphere_shader->set_float("u_Emission", m_black_hole.m_material.m_emission);
+            m_sphere_shader->set_float("u_Specular", m_black_hole.m_material.m_specular);
+            m_sphere_shader->set_float("u_OutlineWidth", 0.3f);
+            
+            m_sphere_vao->bind();
+            RenderCommand::draw_indexed(m_sphere_vao);
+            
+            m_sphere_shader->set_float("u_OutlineWidth", m_outline_width);
+        }
+        
         for (size_t i = 0; i < m_scene.objs.size(); ++i)
         {
             const auto& obj = m_scene.objs[i];
diff --git a/src/states/world_builder_state.h b/src/states/world_builder_state.h
index 4cbe987..866ae59 100644
--- a/src/states/world_builder_state.h
+++ b/src/states/world_builder_state.h
@@ -69,5 +69,8 @@ namespace Donut
 
         glm::vec3 m_outline_color = glm::vec3(1.0f, 1.0f, 1.0f);
         float     m_outline_width = 0.25f;
+        
+        Object m_black_hole;
+        bool   m_black_hole_initialized = false;
     };
 };