GLGraphics 0.9.9.1   1 comment

Suggestions from users of the GLGraphics library led to this new release, 0.9.9.1, which incorporates several enhancements and refinements. Grab zip package from here, and take a look at the detailed release notes here.

Most of the changes in this version with respect to the previous stable release consist of internal improvements (better GLTextureWindow initialization mechanism for example) and a few minor API additions (such as new methods to pass OpenGL matrices to Cg, and additional constructor arguments for GLTextureWindow objects).

There is one new feature though, which exposes the functionality provided by the OpenGL function glDrawRangeElements. This function comes handy when you have to draw a geometry stored in a Vertex Buffer Object (VBO), with a significant amount of vertex redundancy, this is, with some vertices+texture coordinates+color+normal tuples shared among different geometric primitives (triangles, quads, etc). So instead of sending duplicated data to the GPU, only one copy is actually sent, and then an array of indices indicating how to traverse the list of vertices is passed to OpenGL. In this array of vertex indices, one vertex can be referred to multiple times. One important point is that the entity to consider duplicated or not is not the vertex alone, but the combination of vertex + texture coordinates + color + normal vector, as it is discussed here. So the GLModel class now allows to specify a vertex index array to indicate the rendering order of the vertices. The example that shows this new mechanism is MillionCubes. Screenshot below from running this sketch on OSX Snow Leopard with a NVidia Geforce 320M:

million

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Posted January 21, 2011 by ac in Programming

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One response to “GLGraphics 0.9.9.1

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  1. Pingback: Tweets that mention GLGraphics 0.9.9.1 « codeanticode -- Topsy.com

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