Thanks Robert, So in short you are stating that I use a texture atlas approach. The second approach is what I used right now, for every face of the cube construct that side and binding it to the texture which was really inefficient. Well, you have said something about the distortion. I read at nehe's site that you can use mimaps to upload image of any size which will be scaled to the best aspect ratio and will minimize the distortion. Could I use that technique to create the texture atlas? Also, could you give me some pointers or articles which discuss the creation of a texture atlas since I'm fairly new at this.
On Jun 26, 12:01 am, Robert Green <rbgrn....@gmail.com> wrote: > No, that's not what cube maps are for. > > You can only draw 1 texture at a time (unless multitexturing but > that's totally different and not what you want) so you have 2 options: > > 1) Combine all textures together into a single one and map the > coordinates to each side accordingly (will run much faster) > 2) Draw side-at-a-time binding to the appropriate texture for each > side. (not usually the preferred method.) > > A trick many of us use when doing something like... say you want to > have the user pick 6 photos from their SD card and then you want to > display those on a cube, one on each face. At some point you must > load each photo up, clipping and scaling it to fit aspect ratio and a > power-of-two texture and then uploading it to vram. Well, instead of > uploading each one as a separate texture, why not just create a > 1024x1024 bitmap and draw all 6 photos to it in different spots. You > could use 50% of the texture vertically and 33% horizontally (for > example) to pack 6 photos onto it for 100% usage. It's ok if they > distort going on to it so long as you draw them aspect-correct. You > then keep track of which one is where (using UVs, so percentages from > 0 to 1). Upload that texture atlas as a single texture and when you > draw your cube, you just bind to that atlas once and draw everything > in one shot. It'll run fast and it's not really that hard to do. > > On Jun 25, 6:26 pm, chaitanya <vengeance...@gmail.com> wrote: > > > Hi, > > I have just began opengl programming in android and i am fairly > > new to opengl as well. I've been using nehe's opengl tutorials as well > > as insanitydesign's android ports. I successfully managed to create a > > cube with a single texture mapped to all its 6 faces. I even mapped > > multiple textures to different faces of the cube. > > But the way I did it was to create 6 faces seperately, have 6 > > seperate index and texture buffers and then using glBindTexture() with > > the selected texture for each face and then calling glDrawElements. > > Isn't there an efficient way around this. Should i use a cube map > > texture instead of a GL_TEXTURE_2D? > > > Any suggestions would be appreciated? > > Thanks -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
