From 77717ae7c4f7c8f180e5c5e24cf1098c02f3dbf4 Mon Sep 17 00:00:00 2001
From: hachem <im@hachem.wtf>
Date: Fri, 22 Aug 2025 04:48:42 +0200
Subject: feat: add bloom and blur

---
 src/engine/engine.cpp           | 19 +++++++++++++++++++
 src/engine/engine.h             | 12 +++++++++++-
 src/states/simulation_state.cpp | 16 +++++++++++++++-
 3 files changed, 45 insertions(+), 2 deletions(-)

(limited to 'src')

diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index 435b3e0..9a88e9e 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -34,6 +34,7 @@ namespace Donut
 
         m_shader_program  = Ref<Shader>(Shader::create("assets/shaders/compute_texture_quad.glsl"));
         m_compute_program = create_compute_program("assets/shaders/geodesic.glsl");
+        m_blur_shader     = Ref<Shader>(Shader::create("assets/shaders/blur.glsl"));
         
         m_camera_ubo = UniformBuffer::create(128, 1);
         m_disk_ubo   = UniformBuffer::create(sizeof(float) * 5, 2);
@@ -96,6 +97,24 @@ namespace Donut
         RenderCommand::enable_depth_test();
     }
 
+    void Engine::draw_blur_pass()
+    {
+        RenderCommand::set_viewport(0, 0, m_width, m_height);
+        
+        m_blur_shader->bind();
+        m_quad_vao->bind();
+
+        m_texture->bind(0);
+        m_blur_shader->set_int("u_ScreenTexture", 0);
+        m_blur_shader->set_float2("u_Resolution", glm::vec2(m_width, m_height));
+        m_blur_shader->set_float("u_BlurStrength", m_blur_strength);
+        m_blur_shader->set_float("u_GlowIntensity", m_glow_intensity);
+
+        RenderCommand::disable_depth_test();
+        RenderCommand::draw_arrays(6);
+        RenderCommand::enable_depth_test();
+    }
+
     void Engine::dispatch_compute(const Camera& cam)
     {
         int cw = get_compute_width();
diff --git a/src/engine/engine.h b/src/engine/engine.h
index 524f1a7..95cd1f0 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -66,6 +66,7 @@ namespace Donut
         ~Engine() = default;
 
         void draw_full_screen_quad();
+        void draw_blur_pass();
         void dispatch_compute(const Camera& cam);
         void upload_camera_ubo(const Camera& cam);
         void upload_objects_ubo(const std::vector<ObjectData>& objs);
@@ -109,6 +110,12 @@ namespace Donut
         float get_rotation_speed() const { return m_rotation_speed; }
         void  set_rotation_speed(float speed) { m_rotation_speed = speed; }
         
+        float get_blur_strength() const { return m_blur_strength; }
+        void  set_blur_strength(float strength) { m_blur_strength = strength; }
+        
+        float get_glow_intensity() const { return m_glow_intensity; }
+        void  set_glow_intensity(float intensity) { m_glow_intensity = intensity; }
+        
         void load_objects_from_scene(const std::vector<Donut::Object>& objects);
         void export_high_res_frame(const std::string& filename, int width = 4096, int height = 3072);
         void print_object_info() const;
@@ -120,6 +127,7 @@ namespace Donut
         Ref<Texture2D>     m_texture;
         Ref<Shader>        m_shader_program;
         Ref<Shader>        m_compute_program;
+        Ref<Shader>        m_blur_shader;
         Ref<UniformBuffer> m_camera_ubo;
         Ref<UniformBuffer> m_disk_ubo;
         Ref<UniformBuffer> m_objects_ubo;
@@ -145,7 +153,9 @@ namespace Donut
         float m_early_exit_distance = 5e11f;
         
         float m_disk_thickness = 0.1;    
-        float m_disk_density   = 1.2f;
+        float m_disk_density   = 0.1f;
         float m_rotation_speed = 1.0f;
+        float m_blur_strength  = 2.0f;
+        float m_glow_intensity = 0.1f;
     };
 };
diff --git a/src/states/simulation_state.cpp b/src/states/simulation_state.cpp
index 5c75569..6d7ae47 100644
--- a/src/states/simulation_state.cpp
+++ b/src/states/simulation_state.cpp
@@ -60,7 +60,7 @@ namespace Donut
         RenderCommand::set_viewport(0, 0, static_cast<uint32_t>(engine.get_width()), static_cast<uint32_t>(engine.get_height()));
 
         engine.dispatch_compute(engine.get_camera());
-        engine.draw_full_screen_quad();
+        engine.draw_blur_pass();
     }
     
     void SimulationState::on_event(Event& event)
@@ -244,6 +244,20 @@ namespace Donut
         }
         ImGui::TextDisabled("Rotation speed multiplier (0 = no rotation)");
         
+        float blur_strength = engine.get_blur_strength();
+        if (ImGui::SliderFloat("Blur Strength", &blur_strength, 0.5f, 5.0f, "%.2f"))
+        {
+            engine.set_blur_strength(blur_strength);
+        }
+        ImGui::TextDisabled("Blur radius for glow effect");
+        
+        float glow_intensity = engine.get_glow_intensity();
+        if (ImGui::SliderFloat("Glow Intensity", &glow_intensity, 0.1f, 3.0f, "%.2f"))
+        {
+            engine.set_glow_intensity(glow_intensity);
+        }
+        ImGui::TextDisabled("Intensity of the glow effect");
+        
         ImGui::Spacing();
         
         ImGui::TextColored(ImVec4(0.9f, 0.9f, 1.0f, 1.0f), "Camera");
-- 
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