Cameras, Rendering, and Scenes - Mastering Unity Scripting - page 171

• Lines 059-063 : Like OnPostRender , the OnRenderImage event is called
automatically on active camera objects by Unity, once per frame. It's called
after OnPostRender and just before the camera render is presented on
screen. This event provides two arguments, namely, src and dst . The src
argument is a reference to a render texture that contains the completed
render from the camera, which was output from OnPostRender , and the dst
argument reference defines the render texture that will be shown on screen
when the OnRenderImage event completes. In short, this function gives us
an opportunity to edit the pixels of the render either manually in code or
via shader. Here, the Graphics.Blit function is called to copy the source to
the destination render texture using the shader associated with the material
reference Mat .
• Lines 067-085 : Fade is a CoRoutine that transitions a From color to a To color
over the time ( TotalTime ). This CoRoutine method is used to transition
the alpha of a camera color between 0 and 1 , which refer to transparent and
opaque, respectively.
The following screenshot shows the cross-fading camera effect:
Cross-fading cameras