2
\$\begingroup\$

Summary

  • Flickering and shimmering of image plotted on a geometry where the viewport exceeds the size of the screen. I am using an orthographic projection for the camera. In this case, it is tied to THREE's OrthographicCamera where the left,right,top,bottom parameters are -w/2,w/2,-h/2,h/2 and h=height of data and w=width of data.
  • I am rendering a geometry that is larger than the screen viewport, but with the left,right,top,bottom defined above as fitting to the dimensions of the data, the entirety of the data fits on the screen.
  • This geometry is broken into PoT tiles. I am using a LUMINANCE format for texture with a barebones fragment shader (the data itself is float32)
  • The view matrix is based on an orthographic projection where the frustum extends to the extent of the geometry (so the entire geometry is in view)
  • I have both enabled/disabled mipmap generation and have seen the same results below

Issue

For sufficiently large geometries (often 10-100x larger than the viewport) this causes some annoying artifacts that cause the texture to "shimmer" effectively changing the visual representation of the data.

Examples

Here is an example where the camera is panning down the Y-axis (down) in very small values relative to the viewport dimensions and you can see the texture actually appear to change:

Shimmering Example #1

This aliasing effect is definitely apparent in datasets like the one above (a raster plot of a signal)

Here is a second example that shows it a lot more.

Shimmering Example #2

My suspicion is that this is an artifact of the minfilter when there are many texels per pixel. What the heck is going on here!?

\$\endgroup\$

0

You must log in to answer this question.

Browse other questions tagged .