[Mesa-dev] [PATCH v2] anv/cmd_buffer: check for NULL framebuffer

[Jason Ekstrand]

On Fri, Feb 8, 2019 at 7:15 AM Juan A. Suarez Romero <jasuarez at igalia.com>
wrote:

> This can happen when we record a VkCmdDraw in a secondary buffer that
> was created inheriting from the primary buffer, but with the framebuffer
> set to NULL in the VkCommandBufferInheritanceInfo.
>
> Vulkan 1.1.81 spec says that "the application must ensure (using scissor
> if neccesary) that all rendering is contained in the render area [...]
> [which] must be contained within the framebuffer dimesions".
>
> While this should be done by the application, commit 465e5a86 added the
> clamp to the framebuffer size, in case of application does not do it.
> But this requires to know the framebuffer dimensions.
>
> If we do not have a framebuffer at that moment, the best compromise we
> can do is to just apply the scissor as it is, and let the application to
> ensure the rendering is contained in the render area.
>
> v2: do not clamp to framebuffer if there isn't a framebuffer
>
> Fixes: 465e5a86 ("anv: Clamp scissors to the framebuffer boundary")
> CC: Jason Ekstrand <jason at jlekstrand.net>
> ---
>  src/intel/vulkan/gen7_cmd_buffer.c | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/src/intel/vulkan/gen7_cmd_buffer.c
> b/src/intel/vulkan/gen7_cmd_buffer.c
> index 352892aee33..6e3c8079dc5 100644
> --- a/src/intel/vulkan/gen7_cmd_buffer.c
> +++ b/src/intel/vulkan/gen7_cmd_buffer.c
> @@ -70,12 +70,23 @@ gen7_cmd_buffer_emit_scissor(struct anv_cmd_buffer
> *cmd_buffer)
>        };
>
>        const int max = 0xffff;
> +
> +      uint32_t max_height, max_width;
> +
> +      if (fb) {
> +         max_height = fb->height;
> +         max_width = fb->width;
>

Why aren't we clamping here?

Also, I realized while we were e-mailing that if we're in the primary
command buffer, we can actually clamp to renderArea instead of the
framebuffer.  That'd be even better.


> +      } else {
> +         max_height = s->offset.y + s->extent.height;
> +         max_width = s->offset.x + s->extent.width;
> +      }
> +
>        struct GEN7_SCISSOR_RECT scissor = {
>           /* Do this math using int64_t so overflow gets clamped
> correctly. */
>           .ScissorRectangleYMin = clamp_int64(s->offset.y, 0, max),
>           .ScissorRectangleXMin = clamp_int64(s->offset.x, 0, max),
> -         .ScissorRectangleYMax = clamp_int64((uint64_t) s->offset.y +
> s->extent.height - 1, 0, fb->height - 1),
> -         .ScissorRectangleXMax = clamp_int64((uint64_t) s->offset.x +
> s->extent.width - 1, 0, fb->width - 1)
> +         .ScissorRectangleYMax = clamp_int64((uint64_t) s->offset.y +
> s->extent.height - 1, 0, max_height - 1),
> +         .ScissorRectangleXMax = clamp_int64((uint64_t) s->offset.x +
> s->extent.width - 1, 0, max_width - 1)
>        };
>
>        if (s->extent.width <= 0 || s->extent.height <= 0) {
> --
> 2.20.1
>
>
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