shader: Fix disabled and unwritten attributes and varyings

2 files changed, 11 insertions, 3 deletions

diff --git a/src/shader_recompiler/backend/glsl/emit_glsl_context_get_set.cpp b/src/shader_recompiler/backend/glsl/emit_glsl_context_get_set.cpp
index 16e2a8502..d5424301b 100644
--- a/src/shader_recompiler/backend/glsl/emit_glsl_context_get_set.cpp
+++ b/src/shader_recompiler/backend/glsl/emit_glsl_context_get_set.cpp
@@ -179,8 +179,12 @@ void EmitGetAttribute(EmitContext& ctx, IR::Inst& inst, IR::Attribute attr,
     const char swizzle{"xyzw"[element]};
     if (IR::IsGeneric(attr)) {
         const u32 index{IR::GenericAttributeIndex(attr)};
-        if (!ctx.runtime_info.previous_stage_stores.Generic(index)) {
-            ctx.AddF32("{}=0.f;", inst, attr);
+        if (!ctx.runtime_info.previous_stage_stores.Generic(index, element)) {
+            if (element == 3) {
+                ctx.AddF32("{}=1.f;", inst, attr);
+            } else {
+                ctx.AddF32("{}=0.f;", inst, attr);
+            }
             return;
         }
         ctx.AddF32("{}=in_attr{}{}.{};", inst, index, InputVertexIndex(ctx, vertex), swizzle);
diff --git a/src/shader_recompiler/backend/spirv/emit_spirv_context_get_set.cpp b/src/shader_recompiler/backend/spirv/emit_spirv_context_get_set.cpp
index 77fbb2b2f..756de0a27 100644
--- a/src/shader_recompiler/backend/spirv/emit_spirv_context_get_set.cpp
+++ b/src/shader_recompiler/backend/spirv/emit_spirv_context_get_set.cpp
@@ -298,10 +298,14 @@ Id EmitGetAttribute(EmitContext& ctx, IR::Attribute attr, Id vertex) {
     if (IR::IsGeneric(attr)) {
         const u32 index{IR::GenericAttributeIndex(attr)};
         const std::optional<AttrInfo> type{AttrTypes(ctx, index)};
-        if (!type || !ctx.runtime_info.previous_stage_stores.Generic(index)) {
+        if (!type) {
             // Attribute is disabled
             return ctx.Const(0.0f);
         }
+        if (!ctx.runtime_info.previous_stage_stores.Generic(index, element)) {
+            // Varying component is not written
+            return ctx.Const(type && element == 3 ? 1.0f : 0.0f);
+        }
         const Id generic_id{ctx.input_generics.at(index)};
         const Id pointer{AttrPointer(ctx, type->pointer, vertex, generic_id, ctx.Const(element))};
         const Id value{ctx.OpLoad(type->id, pointer)};