From 158a1896ec91c46a43fa3172fa472e6fc7c9eb05 Mon Sep 17 00:00:00 2001
From: Billy Laws <blaws05@gmail.com>
Date: Sat, 18 Feb 2023 18:23:36 +0000
Subject: Implement scaled vertex buffer format emulation

These formats are unsupported by mobile GPUs so they need to be emulated in shaders instead.
---
 .../backend/spirv/spirv_emit_context.cpp           | 61 ++++++++++++++--------
 1 file changed, 40 insertions(+), 21 deletions(-)

(limited to 'src/shader_recompiler/backend/spirv/spirv_emit_context.cpp')

diff --git a/src/shader_recompiler/backend/spirv/spirv_emit_context.cpp b/src/shader_recompiler/backend/spirv/spirv_emit_context.cpp
index 47739794f..fd15f47ea 100644
--- a/src/shader_recompiler/backend/spirv/spirv_emit_context.cpp
+++ b/src/shader_recompiler/backend/spirv/spirv_emit_context.cpp
@@ -25,12 +25,6 @@ enum class Operation {
     FPMax,
 };
 
-struct AttrInfo {
-    Id pointer;
-    Id id;
-    bool needs_cast;
-};
-
 Id ImageType(EmitContext& ctx, const TextureDescriptor& desc) {
     const spv::ImageFormat format{spv::ImageFormat::Unknown};
     const Id type{ctx.F32[1]};
@@ -206,23 +200,37 @@ Id GetAttributeType(EmitContext& ctx, AttributeType type) {
         return ctx.TypeVector(ctx.TypeInt(32, true), 4);
     case AttributeType::UnsignedInt:
         return ctx.U32[4];
+    case AttributeType::SignedScaled:
+        return ctx.profile.support_scaled_attributes ? ctx.F32[4]
+                                                     : ctx.TypeVector(ctx.TypeInt(32, true), 4);
+    case AttributeType::UnsignedScaled:
+        return ctx.profile.support_scaled_attributes ? ctx.F32[4] : ctx.U32[4];
     case AttributeType::Disabled:
         break;
     }
     throw InvalidArgument("Invalid attribute type {}", type);
 }
 
-std::optional<AttrInfo> AttrTypes(EmitContext& ctx, u32 index) {
-    const AttributeType type{ctx.runtime_info.generic_input_types.at(index)};
+InputGenericInfo GetAttributeInfo(EmitContext& ctx, AttributeType type, Id id) {
     switch (type) {
     case AttributeType::Float:
-        return AttrInfo{ctx.input_f32, ctx.F32[1], false};
+        return InputGenericInfo{id, ctx.input_f32, ctx.F32[1], InputGenericLoadOp::None};
     case AttributeType::UnsignedInt:
-        return AttrInfo{ctx.input_u32, ctx.U32[1], true};
+        return InputGenericInfo{id, ctx.input_u32, ctx.U32[1], InputGenericLoadOp::Bitcast};
     case AttributeType::SignedInt:
-        return AttrInfo{ctx.input_s32, ctx.TypeInt(32, true), true};
+        return InputGenericInfo{id, ctx.input_s32, ctx.TypeInt(32, true),
+                                InputGenericLoadOp::Bitcast};
+    case AttributeType::SignedScaled:
+        return ctx.profile.support_scaled_attributes
+                   ? InputGenericInfo{id, ctx.input_f32, ctx.F32[1], InputGenericLoadOp::None}
+                   : InputGenericInfo{id, ctx.input_s32, ctx.TypeInt(32, true),
+                                      InputGenericLoadOp::SToF};
+    case AttributeType::UnsignedScaled:
+        return ctx.profile.support_scaled_attributes
+                   ? InputGenericInfo{id, ctx.input_f32, ctx.F32[1], InputGenericLoadOp::None}
+                   : InputGenericInfo{id, ctx.input_u32, ctx.U32[1], InputGenericLoadOp::UToF};
     case AttributeType::Disabled:
-        return std::nullopt;
+        return InputGenericInfo{};
     }
     throw InvalidArgument("Invalid attribute type {}", type);
 }
@@ -746,18 +754,29 @@ void EmitContext::DefineAttributeMemAccess(const Info& info) {
                 continue;
             }
             AddLabel(labels[label_index]);
-            const auto type{AttrTypes(*this, static_cast<u32>(index))};
-            if (!type) {
+            const auto& generic{input_generics.at(index)};
+            const Id generic_id{generic.id};
+            if (!ValidId(generic_id)) {
                 OpReturnValue(Const(0.0f));
                 ++label_index;
                 continue;
             }
-            const Id generic_id{input_generics.at(index)};
-            const Id pointer{is_array
-                                 ? OpAccessChain(type->pointer, generic_id, vertex, masked_index)
-                                 : OpAccessChain(type->pointer, generic_id, masked_index)};
-            const Id value{OpLoad(type->id, pointer)};
-            const Id result{type->needs_cast ? OpBitcast(F32[1], value) : value};
+            const Id pointer{
+                is_array ? OpAccessChain(generic.pointer_type, generic_id, vertex, masked_index)
+                         : OpAccessChain(generic.pointer_type, generic_id, masked_index)};
+            const Id value{OpLoad(generic.component_type, pointer)};
+            const Id result{[this, generic, value]() {
+                switch (generic.load_op) {
+                case InputGenericLoadOp::Bitcast:
+                    return OpBitcast(F32[1], value);
+                case InputGenericLoadOp::SToF:
+                    return OpConvertSToF(F32[1], value);
+                case InputGenericLoadOp::UToF:
+                    return OpConvertUToF(F32[1], value);
+                default:
+                    return value;
+                };
+            }()};
             OpReturnValue(result);
             ++label_index;
         }
@@ -1457,7 +1476,7 @@ void EmitContext::DefineInputs(const IR::Program& program) {
         const Id id{DefineInput(*this, type, true)};
         Decorate(id, spv::Decoration::Location, static_cast<u32>(index));
         Name(id, fmt::format("in_attr{}", index));
-        input_generics[index] = id;
+        input_generics[index] = GetAttributeInfo(*this, input_type, id);
 
         if (info.passthrough.Generic(index) && profile.support_geometry_shader_passthrough) {
             Decorate(id, spv::Decoration::PassthroughNV);
-- 
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