[Fab] 2D Top Down Spotlight Shadows - Document

 

 

Technical Specifications: Parameters

 

 

1. BP_Spotlight_2D parameters

 

* Light & Shape Controls

 

Radius (Float)
- Controls the maximum reach or distance of the spotlight. Increase this value to cast light and shadows further across the map.

AngleDegree (Float)
- Adjusts the total field of view (FOV) or cone angle of the spotlight in degrees. A wider angle covers a broader area, while a smaller angle creates a narrow, focused beam.

 

 

* Raycasting & Precision Settings

RayStepDegree (Float)

- Determines the structural density and resolution of the shadow-casting rays. Lower values increase the number of raycasts for razor-sharp, precise shadow edges, while higher values optimize performance.

 

* System & Rendering Parameters

z_Height_Offset (Float)

 - Adjusts the vertical positioning (Z-axis offset) of the 2D spotlight mesh. This ensures the light is perfectly layered above the floor tiles but cleanly occluded by wall collisions without clipping.

 

 

 

2. M_Spotlight parameters

 

 01_Base_Color

• Base_Color (Vector / LinearColor)
  • Sets the primary color of the spotlight beam.
• Base_Tex (Texture2D)
  • The source texture used to define the shape or falloff profile of the light beam (e.g., a grayscale gradient mask).
• Use_Base_Texture_Rate (Scalar / Float)
  • Blends or scales the influence of the Base_Tex on the final base color output.
• Base_Tex_Pow (Scalar / Float)
  • Controls the contrast and sharpness of the base texture gradient using a power (exponential) function. Higher values create a sharper falloff with tighter edges.
• Base_Tex_Multiply (Scalar / Float)
  • A multiplier to adjust the overall brightness or intensity of the base color texture pass.

 

 02_Emissive_Color

• Emissive_Color (Vector / LinearColor)
  • Determines the color of the self-illumination (glow) effect, making the spotlight look vibrant and luminous in dark environments.
• Emissive_Tex (Texture2D)
  • The grayscale mask texture used to control the distribution and shape of the emissive glow.
• Use_Emissive_Texture_Rate (Scalar / Float)
  • Adjusts the blending ratio or intensity rate of the emissive texture profile.
• Emissive_Tex_Pow (Scalar / Float)
  • Sharpens or softens the emissive glow gradient. Higher values push the glow toward the center of the beam, while lower values make it spread out more smoothly.
• Emissive_Tex_Multiply (Scalar / Float)
  • Controls the actual glow strength or bloom intensity. Increase this value to make the light appear highly emissive and stand out vividly.

 

 03_Opacity

• Opacity (Scalar / Float)
  • Sets the overall transparency of the spotlight mesh. A value of 1.0 means fully opaque, while lower values make the light beam subtly blend into the background floor and obstacles.