Dieses Dokument ist leider nur in Englisch verfügbar.
Bumpmapping on Simplified Meshes
Introduction
In todays graphics applications like CAD and finite element (FE)
visualization we have to deal with permanently increasing needs for
drawing high resolution meshes at interactive frame rates.
An obvious and often practiced way to achieve this goal is to reduce
the number of triangles and thus the resolution of the original mesh
where the loss is barely visible.
The major problem of simplified meshes is that lots of structures get
lost with increasing degree of reduction.
One solution is to represent these details through texturing the
coarse mesh with the lighting information of the fine one which leads
to a visual result comparable to bumpmaps.
Hardware Acceleration
OpenGL 1.2 provides facilities to implement full Phong-Blinn model
lighting in Hardware. We preserve the normal information of the original
model in a 2D texture which is laid over the reduced mesh.
With the aid of various ColorMatrix and ColorTable
functions we are able to achieve hardware accelerated lighting of the
normal texture. These features can also be found wired in the upcoming
graphics cards generation, still our algorithm has some advantages,
e.g. it allows arbitrary shiny coefficients and runs on every OpenGL 1.2
compliant hardware.
Textures
The normal information of the fine mesh is stored in texture patches,
one patch for each coarse triangle. The alignment of a patch is optimized
regarding size and quality of the resampled result. Finally, all patches
are packed together into one large texture. This needs some
efforts to achieve dense packing respectively to waste as least amount
of texture memory as possible.
Results
Here you can see
some pictures
of the results (click on the picture to load the next one).
