[PATCH 4/7] etnaviv: apply non-alpha workaround to mask

[Russell King]

On Tue, Nov 22, 2016 at 12:44:17PM +0100, Lucas Stach wrote:
> This fixes a lot of rendercheck errors with non-alpha masks.
> 
> Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
> ---
>  etnaviv/etnaviv_render.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/etnaviv/etnaviv_render.c b/etnaviv/etnaviv_render.c
> index d547aefe5c1e..d9feeee55c61 100644
> --- a/etnaviv/etnaviv_render.c
> +++ b/etnaviv/etnaviv_render.c
> @@ -688,6 +688,11 @@ static int etnaviv_accel_composite_masked(PicturePtr pSrc, PicturePtr pMask,
>  	dump_vPix(etnaviv, vMask, 1, "A-MASK%2.2x-%p", op, pMask);
>  #endif
>  
> +	if (etnaviv_workaround_nonalpha(vMask)) {
> +		mask_op.alpha_mode |= VIVS_DE_ALPHA_MODES_GLOBAL_SRC_ALPHA_MODE_GLOBAL;
> +		mask_op.src_alpha = 255;
> +	}
> +

Thinking more about this case, there's a possibility for a big
optimisation here.

The operation is:

	(src IN mask) OP dst

The IN operation is defined as:

	C = Csrc * Amask + Cmask * 0

Since Amask is a constant - 255 - the result is:

	C = Csrc

So, this results in the overall operation becoming:

	src OP dst

Or, in other words, a non-masked blend.  So we can completely eliminate
the complexity of doing a masked blend and use the simpler
etnaviv_accel_composite_srconly().

So, I'm committing this optimisation instead of your patch.

-- 
Russell King