CODEWITHSUNDEEP
unity-game-enginetexturesshadervertex-shader
s_m_w
s_m_w

Reputation: 35

Texture local color accumulation/blur

In simple, I would like my custom shader to have access to its own output during the last frame in order to have a pseudo-motion blur through color accumulation. Although motion blur isn't the correct term at all.

Consider the following: I have a mesh with a mostly transparent texture. The texture offset constantly changes. I would now like to build a shader with which the texture, instead of jumping, slowly fades from the locations it has been at. A full-screen blur effect will not do; the blur has to remain only on the object and needs to be camera-movement independent.

My idea so far has been to define a RenderTexture that would contain the generated texture during the last frame, but since RenderTextures are rendered by a camera which, since all I would like is the mesh-specific texture, I wouldn't know how to implement.

I have also tried to use GrabPass { } in the shader, however that again seems to grab the entire rendered screen rather than the texture.

I may be misunderstanding how shaders work; If rendering the entire screen is the only option, then I could assign my material to a plane and render the texture that way, however I am unsure how, or rather: where in my code, I would do that. Creating a primitive plane as well as a camera just to get a shader to work also seems like it'd be a lot of things required for an effect that, initially, I thought simple to implement. shrug

Any help or pointers would be much appreciated,

- s_m_w

Edit: Here is a very quick mock drawing of what I would like to achieve:

Mock shader

I achieve the current effect by manipulating the texture offset. The "blur" in the second effect needs to be independent from camera movement.

Upvotes: 0

Views: 1453

Answers (1)

Thomas Hilbert
Thomas Hilbert

Reputation: 3629

I think you'll have to render the effect onto a RenderTexture. You can create a Camera in code. You can set its render target to your RenderTexture, and you can conveniently render fullscreen quads using OpenGL commands (GL class). Basically, you can set up the complete effect rendering infrastructure in code.

Frame 1: Set EffectShader source texture to RenderTexture1. Render onto RenderTexture2. Use RenderTexture2 to shade your object using ObjectShader.

Frame 2: Set EffectShader source texture to RenderTexture2. Render onto RenderTexture1. Use RenderTexture1 to shade your object using ObjectShader.

Repeat.

Upvotes: 1

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