Interesting idea, I'll play around with switching to VBOs and see if that helps. What is the difference between a GL_LUMINANCE and GL_RED texture? I didn't even realize LUMINANCE was deprecated. The jogl api we are on doesn't expose GL functionality beyond 2.x. Is it possible to create 8, 16, and 32 bit GL_RED textures?
I have some more info on the bad tiles. I wanted to see if it was a mesh issue so I enabled our code to show the meshes and sudden the tiles all drew correctly under the mesh. Here is an album showing that: AMD Rendering More Info - Imgur
I then switched the mesh color to transparent to see if the images still drew correctly and they did! I then, switched to just drawing a transparent line at 0,0 -> 0,0 and the images still drew correctly. We bulk render multiple images so enabling meshes adds a line draw operation between each image render. When I get a change I was going to switch the mesh drawing logic to draw the meshes AFTER all the images have been drawn and see if it makes a difference. My guess is the images will draw incorrectly still and it has something to do with adding that line draw operation between the image draws.
Edit: Solved the FBO issue by using VBOs for vertex/texture coordinates for the FBO. I wonder if it was because the images being rendered to the FBO were using VBOs but when we went to render the FBO, we didn't use them. I wonder if mixing the two in the same render pass caused issues because once the FBO was rendered to, we could render it on the screen not using VBOs without errors.
Still not sure what the issue with the image tiles is, will try to switch to GL_RED but it sounds like it won't be as efficient since it always uses 32 bits for storing a pixel based on my research.
Edit 2: Tried GL_R16 as the internal format, GL_RED as the format, and GL_SHORT as the type with no luck, still got the ugly tiles occasionally that draw correctly if I draw a line transparent line after each image render.
Thanks
Max