how to make transitions of 2d image

I want to make transitions like novel game(especially Japanese game).

there are various method to transit from image to image.

I have no idea how to make.

as I guess,If I can control pixels and have right masking map, I make complex transition.

If you know methods, components, sameple code or anything can help me, I’m waiting for your idea.

I’m not sure what kinds of transitions you are looking for. You can do a lot with shaders. I don’t have a lot of depth in shader writing, but here is one simple shader that uses the alpha channel of the overlay image to control how the image comes in. With carefully constructed masks, you do things like wipes and window blinds…anything that can be controlled with a mask. The one drawback is that the transition is hard edged.

Shader "Custom/AlphaTestTransition" {
	Properties {
		_Blend ("Blend", Range (0, 1) ) = 0.0 
		_BaseTexture ("Base Texture", 2D) = "" {}
    	_OverlayTexture ("Texture 2 with alpha", 2D) = "" {}

	}
	SubShader {
		Pass {
			SetTexture[_BaseTexture] {combine texture}
		}
		Pass {
			AlphaTest LEQUAL [_Blend]
			SetTexture [_OverlayTexture] { combine texture }
		}
	}
}

There are a variety of different ways textures can be combined in shaders beyond what I’ve done here that might give you what you are looking for. See:

http://docs.unity3d.com/Documentation/Components/SL-SetTexture.html

Try to change smootlhy(Using deltatime) the render settings ambient light(If the image is on plane or something like that)