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Update binding model description comment

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Isaac Marovitz 2024-07-06 22:33:49 +01:00 committed by Isaac Marovitz
parent ea30e543e6
commit 6e80cc6caa
1 changed files with 29 additions and 11 deletions
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src/Ryujinx.Graphics.Shader/CodeGen/Msl/Declarations.cs
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@ -11,7 +11,7 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Msl
static class Declarations
{
/*
* Description of MSL Binding Strategy
* Description of MSL Binding Model
*
* There are a few fundamental differences between how GLSL and MSL handle I/O.
* This comment will set out to describe the reasons why things are done certain ways
@ -19,24 +19,42 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Msl
*
* Main I/O Structs
*
* Each stage will have a main input and output struct labeled as [Stage][In/Out], i.e VertexIn.
* Every attribute within these structs will be labeled with an [[attribute(n)]] property,
* and the overall struct will be labeled with [[stage_in]] for input structs, and defined as the
* Each stage has a main input and output struct (if applicable) labeled as [Stage][In/Out], i.e VertexIn.
* Every field within these structs is labeled with an [[attribute(n)]] property,
* and the overall struct is labeled with [[stage_in]] for input structs, and defined as the
* output type of the main shader function for the output struct. This struct also contains special
* attribute-based properties like [[position]], therefore these are not confined to 'user-defined' variables.
* attribute-based properties like [[position]] that would be "built-ins" in a GLSL context.
*
* These structs are passed as inputs to all inline functions due to containing "built-ins"
* that inline functions assume access to.
*
* Vertex & Zero Buffers
*
* Binding indices 0-16 are reserved for vertex buffers, and binding 18 is reserved for the zero buffer.
*
* Uniforms & Storage Buffers
*
* Uniforms and storage buffers are tightly packed into their respective argument buffers
* (effectively ignoring binding indices at shader level), with each pointer to the corresponding
* struct that defines the layout and fields of these buffers (usually just a single data array), laid
* out one after the other in ascending order of their binding index.
*
* The uniforms argument buffer is always bound at a fixed index of 20.
* The storage buffers argument buffer is always bound at a fixed index of 21.
*
* These structs are passed as inputs to all inline functions as in GLSL or SPIRV,
* uniforms and storage buffers would be globals, and inline functions assume access to these buffers.
*
* Samplers & Textures
*
* Metal does not have a combined image sampler like sampler2D in GLSL, as a result we need to bind
* an individual texture and a sampler object for each instance of a combined image sampler.
* Therefore, the binding indices of straight up textures (i.e. without a sampler) must start
* after the last sampler/texture pair (n + Number of Pairs).
* Samplers and textures are bound in a shared argument buffer. This argument buffer is tightly packed
* (effectively ignoring binding indices at shader level), with texture and their samplers (if present)
* laid out one after the other in ascending order of their binding index.
*
* Uniforms
* The samplers and textures argument buffer is always bound at a fixed index of 22.
*
* MSL does not have a concept of uniforms comparable to that of GLSL. As a result, instead of
* being declared outside of any function body, uniforms are part of the function signature in MSL.
* This applies to anything bound to the shader not included in the main I/O structs.
*/
public static void Declare(CodeGenContext context, StructuredProgramInfo info)