# BRIEF: NFS 2015-Style Wet Perma-Night Scene Setup (Raylib / C)

## 1. Goal
Transform an existing basic 3D scene (containing car model, road surfaces, and city building meshes with flat albedo textures) into a high-contrast, moody, wet perma-night aesthetic inspired by *Need for Speed (2015)*.

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## 2. Technical Stack Context
- **Framework:** Raylib (C/C++)
- **Core APIs:** Custom GLSL Shaders (Shader / Fragment Shaders), `RenderTexture2D` (FBOs), `rlgl` for state/texture management.
- **Goal Output:** Modular shader code and pass-management architecture that runs efficiently on Raylib's forward renderer.

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## 3. Implementation Roadmap & Execution Tasks

### Phase 1: Material & Wetness Shader (`wet_road.fs`)
Modify the primary object shader used for terrain/road surfaces to support a wetness model.

- [ ] **Inputs Needed:**
  - `texture0` (Albedo / Diffuse)
  - `texture1` (Normal Map)
  - `texture2` (Roughness Map or Puddle Noise Mask)
  - Uniform `float u_wetness` (Range: `0.0` to `1.0`)
- [ ] **Shader Logic Requirements:**
  - **Albedo Darkening:** Darken base albedo by ~30–40% on wet areas (porous surfaces darken when saturated).
  - **Roughness Modulation:** Force surface roughness down to near-mirror levels (`~0.02 - 0.1`) based on `u_wetness` and the puddle mask.
  - **Normal Flattening for Puddles:** In high-puddle mask areas, lerp surface normals toward `vec3(0.0, 1.0, 0.0)` to simulate smooth standing water.

### Phase 2: Lighting & Emissive Setup
Configure scene lights and emissive materials for night contrast.

- [ ] **Global Ambient Light:** Lower global ambient color to a dark, cool navy (`RGB: 10, 15, 30`).
- [ ] **Emissive Material Handling:**
  - Add support for an emissive map/uniform on neon signs, building windows, and car light meshes.
  - Multiply emissive output by an intensity factor (`> 2.0`) to ensure they trigger the Bloom threshold in post-processing.
- [ ] **Point & Spot Lights:**
  - Implement dynamic point lights for streetlights and headlights with quadratic distance attenuation (`1.0 / (att_const + att_linear * d + att_quad * d * d)`).

### Phase 3: Post-Processing Framebuffer Pipeline (`main.c`)
Set up offscreen rendering to enable screen-space passes.

- [ ] **Render Texture Setup:**
  - Create a master `RenderTexture2D targetScene` FBO matching screen resolution.
  - Create a secondary `RenderTexture2D pingPongBlur[2]` FBO pair for downscaled bloom processing.
- [ ] **Render Loop Flow:**
  1. `BeginTextureMode(targetScene)` $\rightarrow$ Render all 3D geometry using object shaders.
  2. `EndTextureMode()`
  3. Extract bright pixels from `targetScene` to bloom FBO via threshold shader (`luminance > 0.7`).
  4. Perform horizontal and vertical blur passes on the bright map.
  5. Composite original scene + blurred bloom + final color grading onto the screen.

### Phase 4: Color Grading & Anamorphic Bloom Shader (`post_process.fs`)
Apply the final cinematic "lens" pass over the scene texture.

- [ ] **Heavy / Anamorphic Bloom:**
  - Scale horizontal blur kernel radius larger than vertical to simulate anamorphic lens flares from streetlights and wet ground reflections.
- [ ] **High-Contrast Night LUT / Grading:**
  - Crushed deep blacks (`#050508`).
  - Cool cyan/teal shadows and warm orange/amber highlights for light sources.
- [ ] **Vignette & Lens Effects:**
  - Radial vignette intensity dropping at screen edges.
  - Subtle chromatic aberration (offset Red/Blue channels slightly near screen borders).

### Phase 5: Simple Reflection Pass (Ground / Car)
- [ ] Implement a basic planar reflection pass or sample a low-resolution cubemap probe inside the `wet_road.fs` fragment shader to give wet surfaces mirror-like reflections of the ambient sky and light sources.

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## 4. Deliverables Checklist
1. `wet_material.fs` / `wet_material.vs`: Shader handling albedo darkening, normal mapping, and specular puddle blending.
2. `post_process.fs`: Screen-space shader combining Bloom, Color Grading, Vignette, and Chromatic Aberration.
3. Updated Raylib C loop establishing the `RenderTexture2D` pipeline and uniform bindings.