# PN PerspectiveFx Iwa

#### ● Overview

This effect generates a deep Perlin noise pattern on a horizontal plane.
In addition to the normal noise pattern, there is a mode for outputting as an offset reference image
for the WarpHVIno effect, and a mode for outputting the Fresnel reflection intensity of the water surface
as seen from the camera, when the noise pattern is the water surface wave height.

#### ● Parameters

- Mode : Specify drawing mode. There is a choice of the 4 following modes:

- Noise : Draws a Perlin noise pattern. The noise value is calculated for each sampling
  point obtained by dividing 1 pixel into 100.
- Noise (no resampled) : Draws a Perlin noise pattern. Subpixel processing is not performed
  and results are obtained at high speed, but the noise pattern near the horizon is irregular.
- Warp HV offset : When the noise pattern is set to the level of the water surface, the red
  or green channel is drawn to show how much the light reflected by the water surface is in the
  horizontal or vertical direction.
  By connecting to the WarpHVIno effect's "Hori" and "Vert" ports, you can reproduce the distortion of
  the reflected water surface. You can adjust the shade of the pattern with the "Wave Height" parameter
  described below.
  *Since the WarpHVIno effect port refers by default to the Red channel for both "Hori" and "Vert", channel
  conversion is required on the "Vert" port side, using Channel Selector effect.
- Fresnel reflectivity : When the noise pattern is high or low on the water surface, the Fresnel
  reflection intensity of the water surface as seen from the camera is output in shades. The reflected
  intensity at the bottom of the camera frame is normalized and displayed as 0 brightness. You can adjust
  the shade of the pattern with the "Wave Height" parameter described below.

- Size : Specify the size of the main random pattern.
- Evolution : Specify the expansion of the main random pattern.
- Octaves : Specify how many levels of random pattern to synthesize.
- Offset : Specify the offset position of the first random pattern.
  The right direction of the camera is positive on the X axis, and the back direction of the camera is positive on
  the Y axis.
- p_Intensity : Specify the pattern intensity ratio, between the current generation and the next
  generation.
- p_Size : OSpecify the pattern size ratio, between the current generation and the next generation.
- p_Evolution : Specify the ratio of the pattern evolution period, between the current generation and the next
  generation.
- p_Offset : Specify the pattern offset ratio, between the current generation and the next generation.
- Fov : Specify the vertical angle of view of the camera in degrees.
  When the angle of view is large, the perspective is emphasized (wide angle), and when the angle of view is
  small, the perspective is compressed (telephoto).
- Eye Level : Specify the vanishing point (Horizon line) position of the camera.
- Alpha Rendering : Specifies whether the noise intensity value is also stored in the Alpha channel.
- Wave Height : When the noise pattern is the height of the water surface, specify the difference in wave
  height between the maximum and minimum noise positions.
  Valid only for "Warp HV offset" and "Fresnel reflectivity" modes.