reduce

[thenwithexpandedwingshesteershisflight]

how does reduce work in penumbra ? does it use in a vertex shader to
send vert to a given point with fragments accumulating via gl_blend
gl_func_add ? or does it loop in the fragment shader ?

[Zach Tellman]

It is an iterative shader, which turns a texture into a texture with one-quarter the area. This is repeated until we come to a 1x1 texture.

Zach

[thenwithexpandedwingshesteershisflight]

can I reduce over an area of a texture ? Or put another way, can I
associate a small texture or subset of a texture with every point in
another texture - I want to represent connections between points you
see.

[Zach Tellman]

You can only reduce over the entire texture. However, you can always
render a subset of the full texture to a smaller texture, and reduce
over that.

Zach