[PATCH vkd3d 2/5] include: Document struct vkd3d_shader_scan_descriptor_info.

[Henri Verbeet]

On Thu, 3 Sep 2020 at 05:41, Zebediah Figura <z.figura12 at gmail.com> wrote:
> +/**
> + * The dimension of a shader resource, returned as part of
> + * struct vkd3d_shader_descriptor_info.
> + */
>  enum vkd3d_shader_resource_type
>  {
> +    /**
> +     * The dimension is invalid or not applicable for this resource. This value
> +     * is returned for samplers.
> +     */
>      VKD3D_SHADER_RESOURCE_NONE              = 0x0,
> +    /** Dimensionless buffer. */
>      VKD3D_SHADER_RESOURCE_BUFFER            = 0x1,
> +    /** 1-dimensional texture. */
>      VKD3D_SHADER_RESOURCE_TEXTURE_1D        = 0x2,
> +    /** 2-dimensional texture. */
>      VKD3D_SHADER_RESOURCE_TEXTURE_2D        = 0x3,
> +    /** Multisampled 2-dimensional texture. */
>      VKD3D_SHADER_RESOURCE_TEXTURE_2DMS      = 0x4,
> +    /** 3-dimensional texture. */
>      VKD3D_SHADER_RESOURCE_TEXTURE_3D        = 0x5,
> +    /** Cubemap texture. */
>      VKD3D_SHADER_RESOURCE_TEXTURE_CUBE      = 0x6,
> +    /** 1-dimensional array texture. */
>      VKD3D_SHADER_RESOURCE_TEXTURE_1DARRAY   = 0x7,
> +    /** 2-dimensional array texture. */
>      VKD3D_SHADER_RESOURCE_TEXTURE_2DARRAY   = 0x8,
> +    /** Multisampled 2-dimensional array texture. */
>      VKD3D_SHADER_RESOURCE_TEXTURE_2DMSARRAY = 0x9,
> +    /** Cubemap array texture. */
>      VKD3D_SHADER_RESOURCE_TEXTURE_CUBEARRAY = 0xa,
>
>      VKD3D_FORCE_32_BIT_ENUM(VKD3D_SHADER_RESOURCE_TYPE),
>  };
It's possible to describe this in terms of dimension (although it's a
bit of a stretch to include multisample and arrays there; at that
point "topology" would perhaps be more appropriate), but in that case
it's a little awkward that the enumeration is called
"vkd3d_shader_resource_type".

> +/**
> + * The format of a shader resource, returned as part of
> + * struct vkd3d_shader_descriptor_info. All formats are 32-bit.
> + */
>  enum vkd3d_shader_resource_data_type
>  {
> +    /** Unsigned normalized integer. */
>      VKD3D_SHADER_RESOURCE_DATA_UNORM = 0x1,
> +    /** Signed normalized integer. */
>      VKD3D_SHADER_RESOURCE_DATA_SNORM = 0x2,
> +    /** Signed integer. */
>      VKD3D_SHADER_RESOURCE_DATA_INT   = 0x3,
> +    /** Unsigned integer. */
>      VKD3D_SHADER_RESOURCE_DATA_UINT  = 0x4,
> +    /** IEEE floating-point. */
>      VKD3D_SHADER_RESOURCE_DATA_FLOAT = 0x5,
>
>      VKD3D_FORCE_32_BIT_ENUM(VKD3D_SHADER_RESOURCE_DATA_TYPE),
>  };
>
"Format" tends to have a specific association in the context of these
kinds of APIs. (I.e., VkFormat/DXGI_FORMAT/etc.) What this describes
is more like the type of format; what SPIR-V calls the "sampled type"
(as opposed to the "image format"), and GLSL calls "sampler
type"/"internal texture format"

> +/**
> + * Additional flags describing a shader resource; returned as part of
> + * struct vkd3d_shader_descriptor_info.
> + */
>  enum vkd3d_shader_descriptor_info_flag
>  {
> +    /**
> +     * The counter associated with this UAV resource is read from or written to
> +     * by the shader.
> +     */
>      VKD3D_SHADER_DESCRIPTOR_INFO_FLAG_UAV_COUNTER             = 0x00000001,
> +    /** This UAV resource is read from by the shader. */
>      VKD3D_SHADER_DESCRIPTOR_INFO_FLAG_UAV_READ                = 0x00000002,
> +    /** This sampler is a comparison sampler. */
>      VKD3D_SHADER_DESCRIPTOR_INFO_FLAG_SAMPLER_COMPARISON_MODE = 0x00000004,
>
>      VKD3D_FORCE_32_BIT_ENUM(VKD3D_SHADER_DESCRIPTOR_INFO_FLAG),
>  };
>
Well, they're *descriptor* flags. The SAMPLER_COMPARISON_MODE flag in
particular applies to sampler descriptors, not resource view
descriptors.

> +/**
> + * Describes a single shader resource; returned as part of
> + * struct vkd3d_shader_scan_descriptor_info.
> + */
>  struct vkd3d_shader_descriptor_info
>  {
> +    /** Type of this resource (eg SRV, CBV, UAV, or sampler). */
>      enum vkd3d_shader_descriptor_type type;
> +    /**
> +     * Register space of the resource, or 0 if the shader does not
> +     * support multiple register spaces.
> +     */
>      unsigned int register_space;
> +    /** Register index of the resource. */
>      unsigned int register_index;
> +    /** Dimension of the resource. */
>      enum vkd3d_shader_resource_type resource_type;
> +    /** Format of the data contained in the resource (eg float or integer). */
>      enum vkd3d_shader_resource_data_type resource_data_type;
> -    unsigned int flags; /* vkd3d_shader_descriptor_info_flag */
> +    /**
> +     * Bitwise combination of zero or more members of
> +     * \ref vkd3d_shader_descriptor_info_flag.
> +     */
> +    unsigned int flags;
> +    /** Size of this descriptor array, or 1 if a single descriptor. */
>      unsigned int count;
>  };
>
A bunch more descriptor/resource conflation here. (And, to complicate
it a little more, note that e.g. VKD3D_SHADER_DESCRIPTOR_TYPE_CBV
refers to a descriptor for a *view* into a buffer resource.)