i am new to RTT, and i am now using FrameBuffer.setRenderTarget() to render into textures. (the FrameBuffer is the same one as the main window)
1) i blit white text into a texture after clearing FB with black color. when the texture is applied to a transparent Object3D, the black part is visible. but i have another texture loaded from a grayscale PNG file, where the black part is invisible. why isn't the RTT texture tranparent?
2) the doc says RTT must not use mipmaping. but if a texture will never be rendered into again after the first time, can it have mipmaping afterwards?
3) if a texture has size of 32x32 while the FB is 1280x800, when rendering into the texture, is the renderer doing work on 32x32 pixels or 1280x800 pixels? i mean the workload, is it small or large.