Hi folks.

I have a smallish program which simply loads in an RGB PNG image, changes the format to RGBA, copies the Red channel into the Alpha channel, uploads it as an RGBA texture. Then all I simply want to do is draw textured quads with it. The texturing works fine but for some reason I'm getting this quirky stupid line being drawn accross the image in white. I thought maybe it was the line where the two triangles meet, but even without any rotation of the quads the line is sometimes at slightly different angles and sometimes at a totally different direction altogether. Also sometimes the line goes through the middle of the image while at other times it is off to one side. And furthermore, in some cases I get two or three lines on the same quad all at different angles which seems to change in some way when the quad is positioned at different coordinates.

Has anyone any idea what might be going on here? The blend mode is GL_ONE,GL_ONE. I also have smooth shading enabled with different colors at each vertex. I have no idea why it is producing these weird lines.

I found that GL_ONE,GL_ONE gives the white lines, wheras GL_SRC_ALPHA,GL_ONE does not, even if the source alpha is filled with 1.0. Bizarre!