Integrate SSAO into deferred Vulkan pipeline

[jackthepunished]

Summary

• Remove duplicate SSAO execution and run it once in the dedicated pass stage.
• Wire SSAO blur output into deferred lighting, including descriptor layout/binding updates and ambient modulation in vk_lighting.frag.
• Stabilize SSAO internals (octa normal decode, depth reconstruction, noise upload, persistent samplers, and explicit texture state tracking) and clean small deferred pass leftovers.

Test plan

• cmake --build build --target horizon_game
• cmake --build build
• Launch build/bin/horizon_game.exe for smoke verification
• ctest --test-dir build --output-on-failure (74/76 pass; existing failures: ShaderCompiler reports syntax errors, LinearArena basic operations)

Summary by CodeRabbit

• New Features

  • Screen Space Ambient Occlusion (SSAO) is now fully integrated into the deferred rendering pipeline.
  • Added configurable SSAO settings to control ambient occlusion intensity and quality.

• Improvements

  • Enhanced ambient lighting calculations for more realistic shadowing effects.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 5b72e98d-8a81-4329-86be-64ec8b6d751b

📥 Commits

Reviewing files that changed from the base of the PR and between a505934 and d0e2415.

📒 Files selected for processing (4)

• assets/shaders/deferred/vk_lighting.frag
• assets/shaders/ssao.frag
• engine/renderer/deferred_renderer.cpp
• engine/renderer/deferred_renderer.hpp

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📝 Walkthrough

Walkthrough

The PR refactors the SSAO (Screen Space Ambient Occlusion) implementation to use GLSL 450 descriptor-set bindings and structured uniform blocks, adds octahedral normal decoding, modularizes kernel sampling parameters, integrates SSAO output into deferred lighting, and implements resource state tracking with explicit texture barriers in the renderer.

Changes

Cohort / File(s)	Summary
SSAO Shader Modernization assets/shaders/ssao.frag	Upgraded to GLSL 450, migrated from legacy uniforms to descriptor-set-based bindings and uniform blocks (CameraData, SSAOKernel, SSAOParams). Changed normal decoding from RGB sampling to octahedral .rg decoding. Refactored kernel sampling loop with dynamic kernel_size clamping (1..64), depth delta epsilon handling, and final occlusion power computation (pow(clamp(ao), u_params.power)). Removed standalone uniform declarations for matrices, noise scale, radius, bias, and kernel.
SSAO Lighting Integration assets/shaders/deferred/vk_lighting.frag	Added SSAO texture sampler binding (set=1, binding=5) and integrated SSAO sampling into ambient lighting path, modulating the computed ambient term by SSAO red channel at v_TexCoord.
Deferred Renderer Implementation engine/renderer/deferred_renderer.cpp	Implemented SSAO noise texture initialization via device.update_texture(), refactored sampler management into persistent noise_sampler and blur_sampler members, disabled blending for SSAO pipelines, introduced explicit resource state tracking (raw_state, blur_state) with texture barriers, changed parameter updates to use internal SSAOParams struct, and updated GBuffer descriptor set to bind SSAO blur texture at binding 5.
Deferred Renderer Interface engine/renderer/deferred_renderer.hpp	Added public types SSAOConfig and SSAOPass, introduced execute_ssao_pass() method, added set_ssao_config() and get_ssao_config() configuration API, and added get_ssr_pass() accessor. Integrated SSAO pass as private member m_ssao.

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

Poem

🐰 In descriptor sets, I hop with glee,
Octahedral normals dance wild and free,
SSAO's glow dims the shadows deep,
With power and bias, the rabbits leap!
State tracking true, no barrier's lost—
Deferred dreams rendered at minimal cost! ✨

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feature/ssao-checklist-fixes

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[sonarqubecloud]

Quality Gate failed

Failed conditions
2 Security Hotspots
B Maintainability Rating on New Code (required ≥ A)

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