OpenGL stores the current context in thread-local memory, but commit
4f5baa9a51 removed a runtime.LockOSThread from app.Window that ensured
the goroutine that drives the context stays on the operating thread that
has the context current. This change restores the thread lock.
As a bonus, this change makes the OpenGL contexts responsible for locking
the thread at MakeCurrent, thereby removing LockOSThread calls from GPU
backend-agnostic code.
Fixes: https://todo.sr.ht/~eliasnaur/gio/334
Signed-off-by: Elias Naur <mail@eliasnaur.com>
When extracting headless.Window's content via screenshots,
it can be useful to keep reusing the same image for output,
as well as specify which area of the Window is to be
extracted.
The updated Screenshot method does this by using the supplied
image.
API change: users must pass an existing image to Window.Screenshot.
Signed-off-by: Pierre Curto <pierre.curto@gmail.com>
Ever since commit 8ff654628, the headless implementation has used two
GPU backend (not renderer) instances, one for the renderer and one for
creating the offscreen texture to render into. This arrangment leaks
resources because the backends only clear temporary storage at
BeginFrame, which is not called when reading pixel data from renders.
This change adds an internal constructor, gpu.NewWithDevice, to allow
headless.Window to share its device with the renderer, fixing the leak.
It also makes the code simpler (took me a while to debug this issue); in
fact I'm surprised it even works.
This is not a great fix: it adds an exported yet internal constructor,
and the ownership transfer of the device is surprising enough to warrant
two comments.
Fixes gio#322
Signed-off-by: Elias Naur <mail@eliasnaur.com>
This change implements a Vulkan port for the two renderers, old and
compute. Run with GIORENDERER=forcecompute to test the compute renderer.
To shake out bugs faster, it is also made the default on systems that
support it. To disable Vulkan and force the use of OpenGL, use the
`novulkan` tag:
$ go run -tags novulkan gioui.org/example/kitchen
Don't forget to file an issue describing the issue that prompted the use
of the tag.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
driver.Device.NewFramebuffer doesn't provide additional information over
driver.Device.NewTexture, so Texture can hold its (optional) framebuffer
on behalf of the renderers. Metal don't even need a separate framebuffer
object.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Modern GPU API such as Metal and Vulkan use explicit render passes
and command buffers for recording rendering commands. They don't have
global state; each render pass starts with a clean set of bound
textures, pipeline etc.
Change our GPU abstraction to better match newer API and modify our two
renderers to explicitly describe their render passes.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
There's no meaningful reason to have them separate. The intention was to
enable rendering concurrent with other processing, but that's gaining
framerate at the expense of input latency and complicating ImageOp
semantics.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Both the OpenGL and the Direct3D API are stateful and gpu.GPU renders to
the render target current when Frame is called.
Modern GPU API such as Metal don't have a concept of a current render
target, and the target even changes each frame.
Add RenderTarget and add an explicit target argument to GPU.Frame as
well as the underlying driver.Device.BeginFrame.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
The clear background is the most useful, and the old behaviour can
be achieved by filling the entire viewport with a white paint.ColorOp.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
The CPU fallback of the compute renderer needs ReadPixels data in OpenGL
format (origin at bottom left). Unfortunately, the OpenGL driver
automatically mirrors images in the Y-axis to match the top left origin
image.RGBA.
Remove the mirroring from the driver and introduce a DownloadImage to
restore the old behaviour.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
There are no longer any importers of package backend outside of
gioui.org/gpu. Move it internally, and rename it to the slightly more
specific "driver" while we're at it.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Elias Naur