   Textured translucent sphere producing strange artefacts
  Hi all,I'm developing a simple game using OpenGL & C++ for a Uni. assignment, its a 3rd-person maze/puzzle game. The player controls a soap bubble and has to guide it through the maze without touching anything.I've drawn my soap bubble as a sphere (GLUquadric object) and slapped on a water-ish texture onto it. To give it a more realistic look, I tried making it translucent using blending (see code below), and this is where I run into problems.First, the bubble drawing code: glPushMatrix();// WhiteglColor3f(1.0f, 1.0f, 1.0f);glEnable(GL_BLEND);// Enable 2D texturesglEnable(GL_TEXTURE_2D);// Bind the soap bubble textureglBindTexture(GL_TEXTURE_2D, zakTexture);// Draw the soap bubblegluSphere(circle, zakRadius, 32, 32);   glDisable(GL_BLEND);glPopMatrix();With this code in place, when I start up my game, the soap bubble still has its opaque texture on it. If I leave it for a while, a strange "sweeping" sort of artefact passes over it and then it looks translucent for a while. In a short period of time again, the "sweeping" takes place, and its back to opaque. I've included images below if its any help:Now the weird part: I've tried this out on a non-quadric object (a simple cube made of quads), and it works perfectly. So does this mean that the result I want to achieve is just not possible with a quadric? Or is there some other method to do it for quadrics?So far, I've gone nuts trying everything possible...different textures, adding an alpha channel to the texture, different image formats, Google, GameDev...also tried setting the color to glColor4f(1, 1, 1, 0.5) and using glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)...everything's a no-go. If anyone could give me a solution, or shed some light as to why this happens, I'd be really grateful!Thanks in advance! :)   
  turn off depth writing, call glDepthMask(false); prior to rendering, then re-enable with with true afterwards.Also, dont use gluQuadric functions. Create the geometry yourself so you have more control. I'm pretty sure they have a few... issues.   ;  @ Exorcist : Thanks for your tip, but when I do implement your suggestion, my bubble disappears completely, it doesn't get drawn on screen at all. Any other ideas ?Also, how exactly do you mean "create the geometry yourself" instead of using quadrics? Yes, I'm aware that quadrics have some issues, specially with texture mapping, but how exactly would you suggest I create (for eg:) my soap bubble sphere manually ?Thanks again for your help, others please feel free to drop your thoughts in too.   ;  By creating the geometry yourself, exorcist means grawing the sphere, polygon by polygon, either by using a 3d modelling application and exporting or procedurally with trigonometry at runtime.   ;  @ programmer88:Hmmm, ok...Although that's way more complex stuff than I need, and also the fact that I haven't got the time at this point to either try and draw it in the program using polys/tris, or setup/write a model loader to import it...Thanks for the explanation though :)Any other comments at all as to how I can resolve this issue, assuming that there is some solution to it...?;  Are you setting a blending function?Try something like:glBlendFunc( GL_SRC_ALPHA, GL_ONE );;  @ mightypigeon:Yes, I've tried many combinations of blending equations using glBlendFunc(...), and none of them work out properly - they either keep my bubble opaque, or produce the exact same artefact I described in the beginning.   ;  - SOLVED! -I've managed to fix my problem, and its thanks to Exorcist's suggestion and a little code shifting - I had to draw the bubble ontop of everything else and then use glDepthMask(...) as suggested by Exorcist. Thanks mate!Also many thanks to all the others who took time to reply...much appreciated! :)   