MobileSSAO

SSAO (Screen Space Ambient Occlusion) is a specialized technique designed to enhance visual quality in real-time graphics by adding subtle shadows and depth to scenes, making them appear more realistic. The traditional SSAO approach typically relies on screen space normals, which are used to calculate occlusion effects. However, generating these normals usually requires a separate normal pre-pass, necessitating an extra rendering of objects. This extra step can significantly impact performance, particularly on mobile platforms with limited processing power and resources.

The Mobile SSAO plugin addresses this performance issue by leveraging Multiple Render Targets (MRT) technology. MRT allows the rendering of multiple outputs (such as color, depth, and normals) in a single rendering pass. By using MRT, Mobile SSAO can capture the necessary normal information without needing an additional rendering pass for the normal pre-pass. This optimization reduces the overall rendering workload, which is crucial for maintaining high performance on mobile devices.

Here's a more detailed breakdown of how Mobile SSAO improves performance:

1. MRT Technology: By utilizing MRT, the plugin captures all required data (color, depth, normals) in a single rendering pass. This eliminates the need for a separate normal pre-pass, thus saving computational resources and time.
2. Performance Optimization: The reduction in the number of rendering passes directly translates to improved performance. On mobile devices, where GPU and CPU resources are limited, this optimization helps maintain smooth frame rates and responsiveness.
3. Quality Retention: Despite the performance gains, Mobile SSAO maintains high visual quality by ensuring accurate normal data is available for the SSAO calculations. This balance between performance and quality is essential for mobile gaming and real-time applications.
4. Simplified Rendering Pipeline: Integrating SSAO into the existing rendering pipeline using MRT simplifies the overall rendering process. This streamlined approach reduces the complexity and potential overhead associated with additional rendering passes.
5. VR / XR test: added (OpenXR, stereo rendering verified with Mock Runtime). Experimental XR API integration (Not VR Ready)

In summary, Mobile SSAO's use of MRT technology to combine multiple outputs into a single pass addresses the performance challenges of traditional SSAO on mobile platforms. By avoiding the need for a separate normal pre-pass, it significantly enhances performance while maintaining the visual quality required for realistic ambient occlusion effects. This makes it a valuable tool for developers aiming to achieve high-quality graphics on mobile devices without compromising on performance.

Note: Due to Unity’s rendering behavior on GLES, MSAA must be disabled when using this plugin. For anti-aliasing, please use a post-processing method instead (e.g., FXAA).