// Only one destination texture is supported. This restriction will be lifted
// in the future.
//
- // All destination textures must be exactly of size <width> x <height>.
+ // All destination textures must be exactly of size <width> x <height>,
+ // and must either come from the same ResourcePool the effect uses, or outlive
+ // the EffectChain (otherwise, we could be allocating FBOs that end up being
+ // stale). Textures must also have valid state; in particular, they must either
+ // be mipmap complete or have a non-mipmapped minification mode.
+ //
// width and height can not be zero.
struct DestinationTexture {
GLuint texnum;