[Mesa-dev] [PATCH] blit : only error when the stencil and depth bits do not match (v2)

[Nicolai Hähnle]

Hi Max,

can you explain a bit more about the error you're seeing? It looks like 
the actual functional change is that previously an INVALID_OPERATION 
error was generated when /mask/ includes DEPTH_BUFFER_BIT but either 
source or destination had no depth buffer, and with your change no error 
is generated in this case (and analogously for stencil buffers). Is that 
correct?

On 18.02.2017 15:00, Max Qian wrote:
> From: Maxqia <public at maxqia.com>

Please use your real name as the commit author.

For this part of Mesa, the commit subject should start with 'mesa', e.g. 
just 'mesa:', or perhaps 'mesa/blit:'. A bit more explanation in the 
commit message would also be helpful.

Thanks,
Nicolai

>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97921
> v2 : fix unintentional line removal
> ---
>  src/mesa/main/blit.c | 84 +++++++++++++++++++++-------------------------------
>  1 file changed, 34 insertions(+), 50 deletions(-)
>
> diff --git a/src/mesa/main/blit.c b/src/mesa/main/blit.c
> index e739130f98..7a45354563 100644
> --- a/src/mesa/main/blit.c
> +++ b/src/mesa/main/blit.c
> @@ -334,41 +334,13 @@ _mesa_blit_framebuffer(struct gl_context *ctx,
>           mask &= ~GL_STENCIL_BUFFER_BIT;
>        }
>        else {
> -         int read_z_bits, draw_z_bits;
> -
>           if (_mesa_is_gles3(ctx) && (drawRb == readRb)) {
>              _mesa_error(ctx, GL_INVALID_OPERATION,
>                          "%s(source and destination stencil "
>                          "buffer cannot be the same)", func);
>              return;
>           }
> -
> -         if (_mesa_get_format_bits(readRb->Format, GL_STENCIL_BITS) !=
> -             _mesa_get_format_bits(drawRb->Format, GL_STENCIL_BITS)) {
> -            /* There is no need to check the stencil datatype here, because
> -             * there is only one: GL_UNSIGNED_INT.
> -             */
> -            _mesa_error(ctx, GL_INVALID_OPERATION,
> -                        "%s(stencil attachment format mismatch)", func);
> -            return;
> -         }
> -
> -         read_z_bits = _mesa_get_format_bits(readRb->Format, GL_DEPTH_BITS);
> -         draw_z_bits = _mesa_get_format_bits(drawRb->Format, GL_DEPTH_BITS);
> -
> -         /* If both buffers also have depth data, the depth formats must match
> -          * as well.  If one doesn't have depth, it's not blitted, so we should
> -          * ignore the depth format check.
> -          */
> -         if (read_z_bits > 0 && draw_z_bits > 0 &&
> -             (read_z_bits != draw_z_bits ||
> -              _mesa_get_format_datatype(readRb->Format) !=
> -              _mesa_get_format_datatype(drawRb->Format))) {
> -
> -            _mesa_error(ctx, GL_INVALID_OPERATION,
> -                        "%s(stencil attachment depth format mismatch)", func);
> -            return;
> -         }
> +         // check formats later
>        }
>     }
>
> @@ -388,36 +360,48 @@ _mesa_blit_framebuffer(struct gl_context *ctx,
>           mask &= ~GL_DEPTH_BUFFER_BIT;
>        }
>        else {
> -         int read_s_bit, draw_s_bit;
> -
>           if (_mesa_is_gles3(ctx) && (drawRb == readRb)) {
>              _mesa_error(ctx, GL_INVALID_OPERATION,
>                          "%s(source and destination depth "
>                          "buffer cannot be the same)", func);
>              return;
>           }
> +         // check formats later
> +      }
> +   }
>
> -         if ((_mesa_get_format_bits(readRb->Format, GL_DEPTH_BITS) !=
> -              _mesa_get_format_bits(drawRb->Format, GL_DEPTH_BITS)) ||
> -             (_mesa_get_format_datatype(readRb->Format) !=
> -              _mesa_get_format_datatype(drawRb->Format))) {
> -            _mesa_error(ctx, GL_INVALID_OPERATION,
> -                        "%s(depth attachment format mismatch)", func);
> -            return;
> -         }
> +   /* From the glBlitFramebuffer Spec :
> +    *
> +    * "GL_INVALID_OPERATION is generated if mask contains
> +    *  GL_DEPTH_BUFFER_BIT or GL_STENCIL_BUFFER_BIT and the source and
> +    *  destination depth and stencil formats do not match."
> +    */
> +   if (mask & GL_STENCIL_BUFFER_BIT || mask & GL_DEPTH_BUFFER_BIT) {
> +      struct gl_renderbuffer *readStencilRb =
> +         readFb->Attachment[BUFFER_STENCIL].Renderbuffer;
> +      struct gl_renderbuffer *drawStencilRb =
> +         drawFb->Attachment[BUFFER_STENCIL].Renderbuffer;
> +      struct gl_renderbuffer *readDepthRb =
> +         readFb->Attachment[BUFFER_DEPTH].Renderbuffer;
> +      struct gl_renderbuffer *drawDepthRb =
> +         drawFb->Attachment[BUFFER_DEPTH].Renderbuffer;
>
> -         read_s_bit = _mesa_get_format_bits(readRb->Format, GL_STENCIL_BITS);
> -         draw_s_bit = _mesa_get_format_bits(drawRb->Format, GL_STENCIL_BITS);
> +      int read_z_bits, draw_z_bits, read_s_bit, draw_s_bit;
> +      read_z_bits = _mesa_get_format_bits(readDepthRb->Format, GL_DEPTH_BITS);
> +      draw_z_bits = _mesa_get_format_bits(drawDepthRb->Format, GL_DEPTH_BITS);
> +      boolean depth = read_z_bits > 0 && draw_z_bits > 0 &&
> +          (read_z_bits != draw_z_bits ||
> +           _mesa_get_format_datatype(readDepthRb->Format) !=
> +           _mesa_get_format_datatype(drawDepthRb->Format));
>
> -         /* If both buffers also have stencil data, the stencil formats must
> -          * match as well.  If one doesn't have stencil, it's not blitted, so
> -          * we should ignore the stencil format check.
> -          */
> -         if (read_s_bit > 0 && draw_s_bit > 0 && read_s_bit != draw_s_bit) {
> -            _mesa_error(ctx, GL_INVALID_OPERATION,
> -                        "%s(depth attachment stencil bits mismatch)", func);
> -            return;
> -         }
> +      read_s_bit = _mesa_get_format_bits(readStencilRb->Format, GL_STENCIL_BITS);
> +      draw_s_bit = _mesa_get_format_bits(drawStencilRb->Format, GL_STENCIL_BITS);
> +      boolean stencil = read_s_bit > 0 && draw_s_bit > 0 && read_s_bit != draw_s_bit;
> +
> +      if (stencil && depth) {
> +         _mesa_error(ctx, GL_INVALID_OPERATION,
> +                     "%s(depth attachment stencil bits and format mismatch)", func);
> +         return;
>        }
>     }
>
>