[shader_recompiler] Implement indirect image/texture array indexing (#3608)

Fixes missing textures in Luigi's Mansion 3 (Invisible Mice lol) and potentially other titles
by implementing OpAccessChain indexing into descriptor arrays instead of throwing NotImplementedException.

Co-authored-by: JPikachu <fakemail@gmail.com>
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/3608
Reviewed-by: MaranBr <maranbr@eden-emu.dev>
Reviewed-by: DraVee <dravee@eden-emu.dev>
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>
Co-authored-by: JPikachu <jpikachu@eden-emu.dev>
Co-committed-by: JPikachu <jpikachu@eden-emu.dev>

src/shader_recompiler/backend/spirv/emit_spirv_image.cpp

@@ -197,33 +197,41 @@ Id Texture(EmitContext& ctx, IR::TextureInstInfo info, [[maybe_unused]] const IR
 }
 
 Id TextureImage(EmitContext& ctx, IR::TextureInstInfo info, const IR::Value& index) {
-    if (!index.IsImmediate() || index.U32() != 0) {
-        throw NotImplementedException("Indirect image indexing");
-    }
     if (info.type == TextureType::Buffer) {
         const TextureBufferDefinition& def{ctx.texture_buffers.at(info.descriptor_index)};
         if (def.count > 1) {
-            throw NotImplementedException("Indirect texture sample");
+            const Id idx{index.IsImmediate() ? ctx.Const(index.U32()) : ctx.Def(index)};
+            const Id ptr{ctx.OpAccessChain(ctx.image_buffer_type, def.id, idx)};
+            return ctx.OpLoad(ctx.image_buffer_type, ptr);
         }
         return ctx.OpLoad(ctx.image_buffer_type, def.id);
     } else {
         const TextureDefinition& def{ctx.textures.at(info.descriptor_index)};
         if (def.count > 1) {
-            throw NotImplementedException("Indirect texture sample");
+            const Id idx{index.IsImmediate() ? ctx.Const(index.U32()) : ctx.Def(index)};
+            const Id ptr{ctx.OpAccessChain(def.pointer_type, def.id, idx)};
+            return ctx.OpImage(def.image_type, ctx.OpLoad(def.sampled_type, ptr));
         }
         return ctx.OpImage(def.image_type, ctx.OpLoad(def.sampled_type, def.id));
     }
 }
 
 std::pair<Id, bool> Image(EmitContext& ctx, const IR::Value& index, IR::TextureInstInfo info) {
-    if (!index.IsImmediate() || index.U32() != 0) {
-        throw NotImplementedException("Indirect image indexing");
-    }
     if (info.type == TextureType::Buffer) {
         const ImageBufferDefinition def{ctx.image_buffers.at(info.descriptor_index)};
+        if (def.count > 1) {
+            const Id idx{index.IsImmediate() ? ctx.Const(index.U32()) : ctx.Def(index)};
+            const Id ptr{ctx.OpAccessChain(def.pointer_type, def.id, idx)};
+            return {ctx.OpLoad(def.image_type, ptr), def.is_integer};
+        }
         return {ctx.OpLoad(def.image_type, def.id), def.is_integer};
     } else {
         const ImageDefinition def{ctx.images.at(info.descriptor_index)};
+        if (def.count > 1) {
+            const Id idx{index.IsImmediate() ? ctx.Const(index.U32()) : ctx.Def(index)};
+            const Id ptr{ctx.OpAccessChain(def.pointer_type, def.id, idx)};
+            return {ctx.OpLoad(def.image_type, ptr), def.is_integer};
+        }
         return {ctx.OpLoad(def.image_type, def.id), def.is_integer};
     }
 }

src/shader_recompiler/backend/spirv/spirv_emit_context.cpp

@@ -1331,9 +1331,6 @@ void EmitContext::DefineTextureBuffers(const Info& info, u32& binding) {
 void EmitContext::DefineImageBuffers(const Info& info, u32& binding) {
     image_buffers.reserve(info.image_buffer_descriptors.size());
     for (const ImageBufferDescriptor& desc : info.image_buffer_descriptors) {
-        if (desc.count != 1) {
-            throw NotImplementedException("Array of image buffers");
-        }
         const spv::ImageFormat format{GetImageFormat(desc.format)};
         const Id sampled_type{desc.is_integer ? U32[1] : F32[1]};
         const Id image_type{
@@ -1346,6 +1343,7 @@ void EmitContext::DefineImageBuffers(const Info& info, u32& binding) {
         image_buffers.push_back({
             .id = id,
             .image_type = image_type,
+            .pointer_type = pointer_type,
             .count = desc.count,
             .is_integer = desc.is_integer,
         });
@@ -1389,9 +1387,6 @@ void EmitContext::DefineTextures(const Info& info, u32& binding, u32& scaling_in
 void EmitContext::DefineImages(const Info& info, u32& binding, u32& scaling_index) {
     images.reserve(info.image_descriptors.size());
     for (const ImageDescriptor& desc : info.image_descriptors) {
-        if (desc.count != 1) {
-            throw NotImplementedException("Array of images");
-        }
         const Id sampled_type{desc.is_integer ? U32[1] : F32[1]};
         const Id image_type{ImageType(*this, desc, sampled_type)};
         const Id pointer_type{TypePointer(spv::StorageClass::UniformConstant, image_type)};
@@ -1402,6 +1397,7 @@ void EmitContext::DefineImages(const Info& info, u32& binding, u32& scaling_inde
         images.push_back({
             .id = id,
             .image_type = image_type,
+            .pointer_type = pointer_type,
             .count = desc.count,
             .is_integer = desc.is_integer,
         });

src/shader_recompiler/backend/spirv/spirv_emit_context.h

@@ -51,6 +51,7 @@ struct TextureBufferDefinition {
 struct ImageBufferDefinition {
     Id id;
     Id image_type;
+    Id pointer_type;
     u32 count;
     bool is_integer;
 };
@@ -58,6 +59,7 @@ struct ImageBufferDefinition {
 struct ImageDefinition {
     Id id;
     Id image_type;
+    Id pointer_type;
     u32 count;
     bool is_integer;
 };