GLTexture provides support for uploading and binding OpenGL textures, as well as for managing texture atlases. Image loading is not provided; use pngimageio or your own code.

A GLTexture object can be created directly, or loaded from a serialized representation using the serialization interface. After initial creation, you must upload an image with GLTexture_setImage(). You can then use GLTexture_activate to bind the texture, and GLTexture_deactivate to unbind it.

For performance and/or fine-grained control over texturing, you may not want to use activate() and deactivate(). They're provided only for convenience, and have some properties that may be undesirable in large applications; for example, if autoBlendMode is set to anything other than AUTO_BLEND_MODE_NONE, GL_BLEND will be enabled and/or disabled every time a texture is activated or deactivated. Accessing the textureName directly to bind it yourself is perfectly normal usage of the GLTexture API.

GLTextureAtlas data can be generated using the texturepacker tool. After deserializing a GLTextureAtlas, use the lookup() or getEntryDimensions() method to get the bounds of a particular entry, or the getVertices() or getVerticesWithColor() method to retrieve GL data suitable for drawing.

GLTexture serialization schema:
structure "gltexture" {
	uint16 "format_version" // GLTEXTURE_SERIALIZATION_FORMAT_VERSION
	string "image_name"
	enumeration "bitmap_data_format", GL_ALPHA, GL_LUMINANCE_ALPHA, GL_RGB, GL_RGBA
	enumeration "bitmap_data_type", GL_UNSIGNED_BYTE, GL_UNSIGNED_SHORT_5_6_5, GL_UNSIGNED_SHORT_4_4_4_4, GL_UNSIGNED_SHORT_5_5_5_1
	enumeration "min_filter", GL_NEAREST, GL_LINEAR, GL_NEAREST_MIPMAP_NEAREST, GL_LINEAR_MIPMAP_NEAREST, GL_NEAREST_MIPMAP_LINEAR, GL_LINEAR_MIPMAP_LINEAR
	enumeration "mag_filter", GL_NEAREST, GL_LINEAR
	enumeration "wrap_s", GL_CLAMP_TO_EDGE, GL_REPEAT
	enumeration "wrap_t", GL_CLAMP_TO_EDGE, GL_REPEAT
	enumeration "auto_blend_mode", AUTO_BLEND_MODE_NONE, AUTO_BLEND_MODE_OPAQUE, AUTO_BLEND_MODE_TRANSPARENT_NONPREMULTIPLIED, AUTO_BLEND_MODE_TRANSPARENT_PREMULTIPLIED
	boolean "auto_mipmap"
	boolean "anisotropic_filter"
}

GLTextureAtlas serialization schema:
structure "gltextureatlas" {
	uint16 "format_version" // GLTEXTUREATLAS_SERIALIZATION_FORMAT_VERSION
	string "texture_name"
	dictionary "entries" {
		structure "entry_name" {
			float "left"
			float "right"
			float "bottom"
			float "top"
		}
	}
}