I solved all my problmes, there was a little stupid little issues during the copy of my Vertex and CoordTexture on the buffers.......
Thanks lot however, the theory I read is a good exercise for the next time! Bye! On 28 Dic, 01:52, Robert Green <[email protected]> wrote: > Well said Kostya. > > Pedro - I defined the formula to get your normal above. A normal is a > unit vector (a 3D vector of length 1.) Each vertex must have a normal > for proper shading, as that's how light is calculated. The normal of > a vertex of a sphere is a easy to calculate. Think of it as the > direction from the center of the sphere through the vertex. That's > your vector. I provided a formula, though you'll have to javafy it a > little to make that work for you. If you're struggling to understand > this, I suggest reading some 3D primer books before moving on. They > are very, very helpful. > > Cheers > > On Dec 27, 7:59 am, Kostya Vasilyev <[email protected]> wrote: > > > > > > > > > Pedro, > > > A normal is a unit vector (length == 1) that is perpendicular to the > > surface. Normals are used for shading, so don't worry about them too > > much for now. > > > Texture coordinates, as was already pointed out here, are in 2D space, > > i.e. two coordinates. The reason is that textures are 2-dimensional, and > > texture coordinates specify which point within the texture should be > > mapped to a particular vertex in 3D space. > > > Imagine that the texture is a stretchable, initially square, piece of > > fabric. Each UV coordinate represents a point within that square. > > > For each vertex, the point within the texture specified for that vertex > > by UV coordinates is "glued" to the vertex. Then the texture is allowed > > to stretch between vertexes. > > > What sort of texture coordinates you generate is entirely up to you. > > > A simple way to texture map a sphere is to wrap the texture into a > > vertical cylinder around the sphere, then pull the top and bottom > > towards the sphere, so you have singularities at the top and bottom of > > the sphere. > > > If you generate your sphere as a bunch of horizontal bands, each having > > equal angular size, and further subdivided around into equal patches, > > then you can your use loop variables (band / patch index) to compute UV > > coordinates. Just remember that UV are 0 to 1 (unless you want tiling). > > > -- Kostya > > > 27.12.2010 18:35, pedr0 пишет: > > > > But normal.x what is it? > > > > Is the abs(x) ? > > > > On 23 Dic, 20:41, Robert Green<[email protected]> wrote: > > >> UV unwrapping/mapping is standard practice in 3d games. It's how the > > >> artist lines up the textures onto the skin/model. > > > >> You're doing UV coordinate generation, which is similar but is > > >> mathematically specified instead of placed by a 3D modeling > > >> application. > > > >> On Dec 23, 12:37 am, pedr0<[email protected]> wrote: > > > >>> What do you think about it? > > >>>http://en.wikipedia.org/wiki/UV_mapping > > >>> On 23 Dic, 09:19, pedr0<[email protected]> wrote: > > >>>> Thanks a lot, > > >>>> especially at Robert Green for his very good explanation! > > >>>> The absurd thing is that the code which I posted above is 100% right > > >>>> in a iPhone iOS, but when I port the same code on the Android platform > > >>>> I have these issues. > > >>>> I will try to do what you are talking about normals and I let you know > > >>>> about my progress! > > >>>> Thanks again. > > >>>> pedr0 > > >>>> On 23 Dic, 04:10, Mario Zechner<[email protected]> wrote: > > >>>>> On 22 Dez., 20:42, Robert Green<[email protected]> wrote: > > >>>>>> 3DVec normal = (sphereCenter - point).normalize(); > > >>>>> 3DVec normal = (point - sphereCenter).normalize(); > > >>>>> Or your world will be upside down. Unless my brain is totally > > >>>>> borked :) (could well be, 4am here...) > > > -- > > Kostya Vasilyev -- WiFi Manager + pretty widget > > --http://kmansoft.wordpress.com -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
