From 6e80cc6caad58b82dc2496a2f862d871bc2ac2d3 Mon Sep 17 00:00:00 2001 From: Isaac Marovitz Date: Sat, 6 Jul 2024 22:33:49 +0100 Subject: [PATCH] Update binding model description comment --- .../CodeGen/Msl/Declarations.cs | 40 ++++++++++++++----- 1 file changed, 29 insertions(+), 11 deletions(-) diff --git a/src/Ryujinx.Graphics.Shader/CodeGen/Msl/Declarations.cs b/src/Ryujinx.Graphics.Shader/CodeGen/Msl/Declarations.cs index 18cf36968..d7475357c 100644 --- a/src/Ryujinx.Graphics.Shader/CodeGen/Msl/Declarations.cs +++ b/src/Ryujinx.Graphics.Shader/CodeGen/Msl/Declarations.cs @@ -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)