Rendering a scene with shaderless objects results in a completely black image

Question

I want to do a 2d animation of a particle system.

I created a background, put my camera up, set the mode to orthographic.

I created an object for my particles to use, set them shaderless, created a particle system and chose that object to be rendered.

^{(camera, material and particle properties)}

When I view the animation through the camera it looks nice but when I render the animation, it takes a lot of time and the image comes back just black.

^{(viewport vs render)}

I tried putting up a light, but that didn't work.

blender project file

Answer 1

It's not going to work because of child particles

Unfortunately, since you are rendering child particles, you can't achieve your goal at the moment (Blender 2.79).

This is because the Particle Info node

... currently only supports parent particles. Info from child particles is not available.

I don't know the roadmap for this.

Other details

First, you are currently seeing a good "material" view, because it doesn't rely on Cycles. But if you change to the "rendered" view (you don't have to make an actual render, but it's practically the same), it falls back to black.

Now, even if you disable the "children" in your particle system, it's not going to get any better

this is because your material is, indeed, "shaderless"!

If you add a shader (like the "Emission Shader"), though:

Voilà!

Unfortunately, though, it won't work if you enable child particles again.