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>
We'd like to allow Gio to share a Direct3D context with an embedding
program like the GLFW example does for OpenGL. To do that, d3d11.Device
needs to carry only the minimal information needed (ID3D11Device).
This change moves the caches of ID3D11DepthStencilState and
ID3D11BlendState from from d3d11.Device to d3d11.Backend. It also adds a
Release method for freeing them.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Return the output framebuffer from BeginFrame, to make it clear that
it may change between frames. Delete CurrentFramebuffer which is no
longer needed.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Modern graphics APIs have immutable objects, with mutable data. For example,
a texture's dimensions are immutable, while the texture contents is not.
Change the GPU API abstraction to match.
Clearing a Texture is convenient to do with a plain []byte. Generalize
Texture.Upload to take a plain byte slice and introduce a helper function for
uploading *image.RGBA data.
Add TextureFormatRGBA8 a format for the linear RGB colorspace.
Add OpenGL ES 3.1 functions for compute programs.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Use greater-than-or-equal test and saturate the z depth buffer
when more than 65k objects are drawn.
Fixes gio#127
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Specifying the clear color and depth at the time of clearing is
less error prone and a better for modern GPU APIs. As a bonus, we
can get rid of the BufferAttachment type.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
OpenGL supports casting from int to float during vertex array
reading. Direct3D doesn't. Since we're transpiling from GLSL, we can't
directly use the Direct3D builtin "asint". So that leaves using
"ivec2" instead of vec2.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Elias Naur