Stuart
> Hi All, > > Having seen some recent screenshots from X-Plane 10, I've been > thinking about ways to improve our random scenery, in particular > buildings. > > At present, we have random building scattered over the scenery, based > on .ac models, plus the Urban shader. > > The former are limited in that performance suffers significantly as > density increases, and there is little control over their placement. > The Urban shader provides an good impression of a complex city-scape, > but the sides of the buildings are rather gray, and the visuals suffer > at low viewing angles. It also has a significant performance impact. > > I'm wondering whether there is any mileage in using a variant on the > scheme we use for random vegetation to create a cityscape. As you may > be aware, the random vetegation uses a small number of geomerties > instantiated all over the terrain, and uses a vertex shader (which is > much cheaper than a fragment or geometry shader) to provide height, > width and texture information. > > Of course, there's no point at all in doing this unless it provides > better performance than the urban shader. > > The Default materials.xml tree density is 4000m^2, or a tree per > 63mx63m square (ish). The trees themselves have similar geometric > complexity to a cuboid (same number of vertices), but buildings don't > generally have any alpha blending requirements. So to a first level of > approximation, we should be able to populate the urban area with > textured cubeoids at the same density as the trees for a similar cost > performance-wise. > > To provide more interesting buildings, I'm anticipating using a cuboid > per floor, plus a modified cuboid for the roof, so probably ~ 4x the > complexity of trees geometrically for a 3 storey building. Obviously > there would be XML controls in materials.xml (or a linked XML file) > for the length, width, number of floors, textures, and roof. > > At the same time, I'm anticipating aligning the buildings with the > texture, and probably using a second texture as a mask to indicate > where buildings may, or may not, be placed. This latter technique may > also have applications for the trees, so that trees only appear a the > edges of fields, or in the "rough" of golf courses. > > I'm interested in peoples opinions on this, and in particular what > their view is of the current forest and urban shader performance. It > may be that my system is unique in that one is cheap and the other > expensive, and this is all pointless! > Sounds a good idea - I hate the random objects - they are always the wrong style/size and in the wrong place. Just do it - we'll make it switchable at runtime. Users can make up their own minds (or as it has been said of users: what they are pleased to call their minds). Looking forward to testing it, Vivian ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-novd2d _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
