[Mesa-dev] [RFC 3/3] mesa: call DrawBuffer(s) driver hook in update_framebuffer for windows-system FB

[Timothy Arceri]

On 14/04/18 14:45, Timothy Arceri wrote:
> From: Boyan Ding <boyan.j.ding at gmail.com>
> 
> When draw buffers are changed on a bound framebuffer, DrawBuffer(s) hook
> should be called. However, it is missing in update_framebuffer with
> window-system framebuffer, in which FB's draw buffer state should match
> context state, potentially resulting in a change.
> 
> Note: This seems to be needed because gallium delays creating the front
> buffer. i965 works fine without this change.

Meant to add here:

Fixes a number of Wine apps and the following piglit test on gallium:

./bin/glx-multi-context-front


> 
> V2 (Timothy Arceri):
>   - Rebased on merged/simplified DrawBuffer driver function
>   - Move DrawBuffer call outside fb->ColorDrawBuffer[0] !=
>     ctx->Color.DrawBuffer[0] check to make piglit pass.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99116
> ---
>   src/mesa/main/framebuffer.c | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/src/mesa/main/framebuffer.c b/src/mesa/main/framebuffer.c
> index 249e775f8cb..81d3b370e73 100644
> --- a/src/mesa/main/framebuffer.c
> +++ b/src/mesa/main/framebuffer.c
> @@ -623,6 +623,12 @@ update_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb)
>            _mesa_drawbuffers(ctx, fb, ctx->Const.MaxDrawBuffers,
>                              ctx->Color.DrawBuffer, NULL);
>         }
> +
> +      /* Call device driver function if fb is the bound draw buffer. */
> +      if (fb == ctx->DrawBuffer) {
> +         if (ctx->Driver.DrawBuffer)
> +            ctx->Driver.DrawBuffer(ctx);
> +      }
>      }
>      else {
>         /* This is a user-created framebuffer.
>