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- Changes in version 3.0 vs. version 2.1
-
- - Pure z-buffer replaced with a more powerful "pixel-buffer" which
- allow transparent surfaces to be rendered. Transparency is controlled
- in the shaders which allow interesing effects, like
- "transparency-mapping"
-
- - Shadow casting supported through depth-maps.
-
- - A more general lightsource concept which make it possible to have
- colored lightsources of different kind, turn these on and off and
- manipulate them in various other ways.
-
- - It is possible to create several virtual cameras and then use
- any of them as viewpoint in a rendering.
-
- - Viewing vectors sent to the shaders are no longer an approximation.
-
- - Shaders can be more powerful since more information is sent to them,
- and a more flexibel shader-lightsource interface is used.
-
- - A background color can be specified.
-
- - Texture coordinate interpolation is finally done right (I hope...)
-
- - Bezier patches and surfaces of revoultion can be created with a
- simple function call instead of reading them from a file in our
- weird format.
-
- - All object primitives can now be created with one of a few different
- texture coordinate mappings.
-
- - A new shader: The familiar Phong illumination model.
-
- - A complete user manual in texinfo format.
-
-
- Changes in version 2.1 vs. version 2.0.*
-
- - Support for more rendering modes: Phong, Gouraud, flat and line.
- Only Phong mode can do real texture mapping though.
-
- - Support for rendering into other places than files. We have chosen
- to call this rendering into pixmaps, but there is no restriction on
- what is really used. This is accomplished through a callback function
- similar to the shader interface. A basic implementation of pixmaps
- and bitmaps that could be used are supplied in the library.
-
- - Oversampling for antialiasing can now be arbitrarily large.
-
- - It is possible to turn off backface culling. This is useful if you
- have a database of objects that are inconsequent in the ordering
- of its vertices (clockwize/counterclockwize).
-
- - Two new object primitives, cone and prism.
- Thanks to David Jones (djones@awesome.berkeley.edu) for these.
-
- - Two new shaders.
- 1. strauss_shader() - This is an implementation of the shading
- model designed by Paul S. Strauss at Silicon Graphics Inc.
- and described in IEEE CG&A November 1990.
- 2. wood_shader() - A shader that simulates wood texture using
- noise and turbulence.
-
- - Matrix and vector handling functions and macros are now "public".
-
- - Correct interpolation of texture coordinates. Previously there
- were disturbing "rubberband" effects on objects spanning large
- depths in the picture.
-
- - A full polygon clipper is now used instead of the previous, rather
- strange approach. Objects behind the viewpoint are now handled correctly
- (I hope), previously they caused strange effects.
-
- - It is possible to get the current transformation matrix from an object
- and not only to set it. This makes it a lot easier to do animations.
-
- - Subobjects and surfaces can now be removed from objects.
-