[PATCH] wined3d: Support D3DFMT_L8 format as render target when supported by GPU.

[Henri Verbeet]

On 23 March 2016 at 15:06, Paul Gofman <gofmanp at gmail.com> wrote:
> On 03/23/2016 04:37 PM, Henri Verbeet wrote:
>> Is this needed by an application? Luminance formats aren't supposed to
>> be color-renderable according to the OpenGL spec, and that's why
>> you're getting GL_INVALID_ENUM in query_internal_format(). Does NVIDIA
>> have some extension that allows this?
> This is somehow used with a Unity3D game. This makes it work flawlessly
> with Nvidia under Wine. Though I found later that the same works under
> Windows 7 with the similar Intel GPU (where Luminance is not allowed as
> render target according to my test), so apparently it might work without
> it somehow but I did not find yet what lets them get along without this
> format. With Nvidia under Windows 7 unity uses Directx 11 (actually it
> tries the same under Wine unless d3dx11.dll is disabled).
How does it fail exactly? Does it fail to create a render target, or
does it just not like the result from CheckDeviceFormat()? Is there
any chance it would be happy with some other format instead, like e.g.
R8_UNORM? For what it's worth, I just checked on Windows, and both L8
and L16 seem to be supported as render targets on AMD as well.

> I know that GL spec does not suppose luminance as render target, and I
> could not find any extension on Nvidia so far which is responsible for
> allowing that. It just allows it, and does not give an error for
> glGetInternalformativ.
I'd like to avoid rendering to GL_LUMINANCE8 if we can, but GL_R8 with
appropriate swizzles may be an alternative. We'll need that to
implement luminance formats for core profiles anyway, and Matteo has a
patch for that. That patch doesn't enable WINED3DFMT_FLAG_RENDERTARGET
on WINED3DFMT_L8_UNORM yet, but it should be easy to add.

> I can change the whole test to use different values to have different
> red and green channels after blending. I am just not sure how can I
> guess "broken" values for D3DMT_L8, as I do not have any hardware which
> has D3DFMT_L8 supported as RT and POSTPIXELSHADER_BLENDING not supported.
>
In theory the values should simply be the same as with
D3DRS_ALPHABLENDENABLE disabled.