Copies gl_mem into the texture specified by tex_id. The format of tex_id
is specified by tex_format, width and height.
If respecify is true, then the copy is performed in terms of the texture
data. This is useful for splitting RGBA textures into RG or R textures or
vice versa. The requirement for this to succeed is that the backing texture
data must be the same size, i.e. say a RGBA8 texture is converted into a RG8
texture, then the RG texture must have twice as many pixels available for
output as the RGBA texture.
Otherwise, if respecify is false, then the copy is performed per texel
using glCopyTexImage. See the OpenGL specification for details on the
mappings between texture formats.
Copies gl_mem into the texture specified by tex_id. The format of tex_id is specified by tex_format, width and height.
If respecify is true, then the copy is performed in terms of the texture data. This is useful for splitting RGBA textures into RG or R textures or vice versa. The requirement for this to succeed is that the backing texture data must be the same size, i.e. say a RGBA8 texture is converted into a RG8 texture, then the RG texture must have twice as many pixels available for output as the RGBA texture.
Otherwise, if respecify is false, then the copy is performed per texel using glCopyTexImage. See the OpenGL specification for details on the mappings between texture formats.