NewDevice creates a Device given an API, which is the necessary GPU
resources for a backend.
Convert gpu.New to take an API instead of a backend.Device directly.
In turn, this frees us to later unexport the backend package along with
the backend implementations (for now just gioui.org/gpu/gl for OpenGL).
It also allows programs that embed Gio (such as gioui.org/example/glfw)
to freely choose a backend, not just OpenGL.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Bind the framebuffer as late as possible to lessen the risk of
confusing global state (current framebuffer). Commit
25a19481e3 removed the assumption
that the framebuffer current at gpu.New would always be the output
framebuffer
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Gio UI may be overlaid on top of custom graphics such as in the glfw example.
That will only work if Gio doesn't clear the screen (to white).
Signed-off-by: Elias Naur <mail@eliasnaur.com>
While here, merge BeginFrame and EndFrame; the split was done for
performance reasons, yet never measured.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Add a series of low level gpu.Backend tests to assure the correct behaviour of
Backends. The immediate use is debugging of the Direct3D port, in the future
for developing new backends.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
The new Framebuffer.ReadPixels method is enough to implement
Window.Screenshot. Use that instead of the OpenGL-specific
implementation.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
To prepare package headless for multiple backends, refactor the common headless
driver to no longer assume an OpenGL context. Instead, introduce a headless
backend type and the OpenGL implementation, glBackend.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
This is a refactoring change to prepare for another gpu.Backend
implementations.
Notably, app/loop.go no longer imports gpu/gl.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
A recent change made the OpenGL functions an interface of the functions
required for the implementation of GPU, a renderer for Gio operations.
That allowed for running Gio on external systems where OpenGL is
available.
However, to allow for non-OpenGL flavored backends such as Vulkan,
Metal and Direct3D, this change introduces Backend for the high-level
operations required by GPU. This change also adds a concrete backend
to package gl.
Type Backend is a first cut heavily based on OpenGL. Future changes will add
more backends, where the Backend interface quite possibly will need refinement.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
The rendering implementation is needed for using Gio UI with external
window libraries such as GLFW. Expose it in the new package gpu.
Updates #26
Signed-off-by: Elias Naur <mail@eliasnaur.com>
We'd like to support Gio using a different renderer binding than
the builtin. A first step is to define the Functions interface
in package gl, and extract the concrete implementations to a
separate package.
Updates #26
Signed-off-by: Elias Naur <mail@eliasnaur.com>
The origin of image.Images is the upper left corner. Convert the
ReadPixels result by flipping the image the y-direction.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Elias Naur