[Mesa-dev] [PATCH v2 10/16] mesa: Add draw time validation for advanced blending modes.

[Francisco Jerez]

Kenneth Graunke <kenneth at whitecape.org> writes:

> Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
> ---
>  src/mesa/main/context.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 51 insertions(+)
>
> diff --git a/src/mesa/main/context.c b/src/mesa/main/context.c
> index 4ff0979..e63d8a6 100644
> --- a/src/mesa/main/context.c
> +++ b/src/mesa/main/context.c
> @@ -1876,6 +1876,57 @@ check_blend_func_error(struct gl_context *ctx)
>  	 return false;
>        }
>     }
> +
> +   if (ctx->Color.BlendEnabled && ctx->Color._AdvancedBlendMode) {
> +      /* The KHR_blend_equation_advanced spec says:
> +       *
> +       *    "If any non-NONE draw buffer uses a blend equation found in table
> +       *     X.1 or X.2, the error INVALID_OPERATION is generated by Begin or
> +       *     any operation that implicitly calls Begin (such as DrawElements)
> +       *     if:
> +       *
> +       *       * the draw buffer for color output zero selects multiple color
> +       *         buffers (e.g., FRONT_AND_BACK in the default framebuffer); or
> +       *
> +       *       * the draw buffer for any other color output is not NONE."
> +       */
> +      if (ctx->DrawBuffer->ColorDrawBuffer[0] == GL_FRONT_AND_BACK) {
> +         _mesa_error(ctx, GL_INVALID_OPERATION,
> +                     "advanced blending is active and draw buffer for color "
> +                     "output zero selects multiple color buffers");
> +         return false;
> +      }
> +
> +      for (unsigned i = 1; i < ctx->DrawBuffer->_NumColorDrawBuffers; i++) {
> +         if (ctx->DrawBuffer->ColorDrawBuffer[i] != GL_NONE) {
> +            _mesa_error(ctx, GL_INVALID_OPERATION,
> +                        "advanced blending is active with multiple color "
> +                        "draw buffers");
> +            return false;
> +         }
> +      }
> +
> +      /* The KHR_blend_equation_advanced spec says:
> +       *
> +       *    "Advanced blending equations require the use of a fragment shader
> +       *     with a matching "blend_support" layout qualifier.  If the current
> +       *     blend equation is found in table X.1 or X.2, and the active
> +       *     fragment shader does not include the layout qualifier matching
> +       *     the blend equation or "blend_support_all_equations", the error
> +       *     INVALID_OPERATION is generated [...]"
> +       */
> +      struct gl_shader_program *sh_prog = ctx->_Shader->_CurrentFragmentProgram;
> +      struct gl_shader_info *fs_info =
> +         &sh_prog->_LinkedShaders[MESA_SHADER_FRAGMENT]->info;

Don't you need a NULL check here to avoid a crash if
there is no valid fragment program bound to the pipeline?  You could
also declare the variables above as pointers to const.  With that fixed:

Reviewed-by: Francisco Jerez <currojerez at riseup.net>

> +
> +      if ((fs_info->BlendSupport & ctx->Color._AdvancedBlendMode) == 0) {
> +         _mesa_error(ctx, GL_INVALID_OPERATION,
> +                     "fragment shader does not allow advanced blending mode "
> +                     "(%s)",
> +                      _mesa_enum_to_string(ctx->Color.Blend[0].EquationRGB));
> +      }
> +   }
> +
>     return true;
>  }
>  
> -- 
> 2.9.3
>
> _______________________________________________
> mesa-dev mailing list
> mesa-dev at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 212 bytes
Desc: not available
URL: <https://lists.freedesktop.org/archives/mesa-dev/attachments/20160822/0b3cf4de/attachment.sig>