# Plan: Implement "Force Lossless" Format for Specific Map Types

**Goal:** Modify the asset processor to ensure specific map types ("NRM", "DISP") are always saved in a lossless format (PNG or EXR based on bit depth), overriding the JPG threshold and input format rules. This rule should apply to both individually processed maps and merged maps.

**Steps:**

1.  **Add Configuration Setting (`config.py`):**
    *   Introduce a new list named `FORCE_LOSSLESS_MAP_TYPES` in `config.py`.
    *   Populate this list: `FORCE_LOSSLESS_MAP_TYPES = ["NRM", "DISP"]`.

2.  **Expose Setting in `Configuration` Class (`configuration.py`):**
    *   Add a default value for `FORCE_LOSSLESS_MAP_TYPES` in the `_load_core_config` method's `default_core_settings` dictionary.
    *   Add a new property to the `Configuration` class to access this list:
        ```python
        @property
        def force_lossless_map_types(self) -> list:
            """Gets the list of map types that must always be saved losslessly."""
            return self._core_settings.get('FORCE_LOSSLESS_MAP_TYPES', [])
        ```

3.  **Modify `_process_maps` Method (`asset_processor.py`):**
    *   Locate the section determining the output format (around line 805).
    *   **Before** the `if output_bit_depth == 8 and target_dim >= threshold:` check (line 811), insert the new logic:
        *   Check if the current `map_type` is in `self.config.force_lossless_map_types`.
        *   If yes, determine the appropriate lossless format (`png` or configured 16-bit format like `exr`) based on `output_bit_depth`, set `output_format`, `output_ext`, `save_params`, and `needs_float16` accordingly, and skip the subsequent `elif` / `else` blocks for format determination.
        *   Use an `elif` for the existing JPG threshold check and the final `else` for the rule-based logic, ensuring they only run if `force_lossless` is false.

4.  **Modify `_merge_maps` Method (`asset_processor.py`):**
    *   Locate the section determining the output format for the merged map (around line 1151).
    *   **Before** the `if output_bit_depth == 8 and target_dim >= threshold:` check (line 1158), insert similar logic as in step 3:
        *   Check if the `output_map_type` (the type of the *merged* map) is in `self.config.force_lossless_map_types`.
        *   If yes, determine the appropriate lossless format based on the merged map's `output_bit_depth`, set `output_format`, `output_ext`, `save_params`, and `needs_float16`, and skip the subsequent `elif` / `else` blocks.
        *   Use `elif` and `else` for the existing threshold and hierarchy logic.

**Process Flow Diagram:**

```mermaid
graph TD
    subgraph Format Determination (per resolution, _process_maps & _merge_maps)
        A[Start] --> B(Get map_type / output_map_type);
        B --> C{Determine output_bit_depth};
        C --> D{Is map_type in FORCE_LOSSLESS_MAP_TYPES?};
        D -- Yes --> E[Set format = Lossless (PNG/EXR based on bit_depth)];
        D -- No --> F{Is output_bit_depth == 8 AND target_dim >= threshold?};
        F -- Yes --> G[Set format = JPG];
        F -- No --> H[Set format based on input/hierarchy/rules];
        G --> I[Set Save Params];
        H --> I;
        E --> I;
        I --> J[Save Image];
    end