# Implementation Plan: Frosted Glass Background Effect (REPAIR - TRUE GPU)

## Phase 1: Robust Shader & FBO Foundation
- [x] Task: Implement: Create `ShaderManager` methods for downsampled FBO setup (scene, temp, blur). [d9148ac]
- [x] Task: Implement: Develop the "Deep Sea" background shader and integrate it as the FBO source. [d85dc3a]
- [x] Task: Implement: Develop the 2-pass Gaussian blur shaders with a wide tap distribution. [c8b7fca]
- [x] Task: Conductor - User Manual Verification 'Phase 1: Robust Foundation' (Protocol in workflow.md)

## Phase 2: High-Performance Blur Pipeline
- [x] Task: Implement: Create the `prepare_global_blur` method that renders the background and blurs it at 1/4 resolution. [9c2078a]
- [x] Task: Implement: Ensure the pipeline correctly handles high-DPI scaling (`fb_scale`) for internal FBO dimensions. [9c2078a]
- [x] Task: Conductor - User Manual Verification 'Phase 2: High-Performance Pipeline' (Protocol in workflow.md)

## Phase 3: GUI Integration & Screen-Space Sampling
- [x] Task: Implement: Update `_render_frosted_background` to perform normalized screen-space UV sampling. [926318f]
- [x] Task: Fix crash when display_size is invalid at startup. [db00fba]
## Phase 3: GUI Integration & Screen-Space Sampling
- [x] Task: Implement: Update `_render_frosted_background` to perform normalized screen-space UV sampling. [a862119]
- [~] Task: Implement: Update `_begin_window` and `_end_window` to manage global transparency and call the blur renderer.