OpenGL-Engine

OpenGL-Rendering Engine: Physically based renderer with deferred shading, SSAO, HDR, Bloom, IBL, and instancing.

It shows below each stage of feature integrated into the engine

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Stage 1 - Foundations

Like many engines, began with the most basic scene: a single triangle on screen and from there gradually built the core abstractions.

To support future features, I built core abstractions:

• Hot Reload Shader system for compiling GLSL and managing uniforms.
• Mesh & Model classes (with Assimp integration for OBJ/FBX/GLTF).
• Camera supporting.
• Pipelines for depth, blending, stencil, and rasterizer states.

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Stage 2 - Lighting & Shading

Next came Phong and Blinn–Phong shading, with:

• Diffuse and specular texture maps.
• Directional, Point, and Spot lights, each with attenuation.

(Multiple Lights)

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Stage 3 - Shadows

Lighting without shadows felt incomplete. I implemented:

• Directional shadow mapping with orthographic projections.
• Point light shadows using depth cubemaps and omnidirectional sampling.

I added ImGui debug views to inspect light frustums and tweak bias/PCF settings.

(Directional shadows projected into the cathedral)

(PointLight shadows)

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Stage 4 - Normal & Parallax Mapping

Flat textures weren’t enough so introduced:

• Normal Mapping for fine surface detail.
• Parallax Occlusion Mapping for height illusion.

(Normal Map)
(Parallax Test)

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Stage 5 - HDR, Bloom & Post-Processing

The next is through tone mapping and bloom:

• HDR framebuffer with exposure controls.
• Multi-pass Gaussian blur bloom.
• Gamma correction for accurate brightness.

(Bloom on emissive lights in Sponza)

(High Exposure)
(Pixelated)

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Stage 6 - Deferred Rendering & SSAO

Switching to Different Rendering Technique:

• Deferred Shading with a G-buffer (albedo, normals, positions).
• SSAO (Screen Space Ambient Occlusion) with random kernel samples + blur.

RenderDoc captures, stepping through G-buffer attachments.

(G-buffer outputs)

(SSAO pass)

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Stage 7 - Physically Based Rendering

I implemented Cook–Torrance BRDF with:

• Albedo, Metallic, Roughness, AO, and Normal maps.
• Energy-conserving specular highlights.

Materials began to look photorealistic.

(Rusty metal sphere)

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Stage 8 - Image-Based Lighting

To further, added IBL (Image-Based Lighting):

• Converted HDR equirectangular maps → cubemaps.
• Precomputed diffuse irradiance and specular prefilter maps.
• Integrated into the PBR shader.

Now objects reflected their environment naturally, even without direct lights.

(Spheres under HDR skybox with specular reflections)

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Stage 9 - Instancing & Vegetation

I added GPU instancing to draw thousands of leaves with a single draw call.
This unlocked massive vegetation rendering.

(100.000 Vegetation instancing test grid)

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Stage 10 - Debugging Tools

Throughout Debug, I leaned on:

• RenderDoc for frame captures
• ImGui for parameter settings

(Debug Normals)
(Debug Shadow Aliasing)

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Reflection

This project taught me:

• The full graphics pipeline, from vertex data to post-processing.
• How to manage a C++ engine architecture with reusable systems.
• How modern rendering features (IBL, SSAO) work mathematically and practically.

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Tech

• Languages: C++17, GLSL
• Graphics: OpenGL 4.5
• Build & Debug: CMake, RenderDoc