Alpha Blending

tyreth · 2001-11-23T22:13:09

Hello I have been trying for quite a while now to get alpha blending working properly. I am using SDL 1.23, SDL Image 1.20, and OpenGL in Linux. I use SDL Image to load the image (png, bmp, tga I have tried I think). I bhave a 3D application, and am trying to create a cursor. I can get the cursor to draw, but not with proper blending. For example, glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); which was recommended in NeHe''s tutorials caused nothing to blend. I tried various combinations for glBlendFunc (not knowing fully what they do), and received mixed results - the best being the supposedly transparent area being totally transparent, but the colored areas still being semi-transparent. Help using SDL Image to load a png, and so that only the transparent bit is transparent, and the rest is solid would be much appreciated. The problem may be with the alpha channel not being properly setup, so help doing this with the GIMP would also be useful. (when I load my png image in the gimp, it shows the transparent area as the grey grids you normally get). Thanks for any help Tyreth