shader/texture: Allow 2D shadow arrays and simplify code

Shadow sampler 2D arrays are supported on OpenGL, so there's no reason
to forbid these. Enable textureLod usage on these.

Minor style changes.

src/video_core/shader/decode/texture.cpp

@@ -522,68 +522,53 @@ Node4 ShaderIR::GetTextureCode(Instruction instr, TextureType texture_type,
                                Node array, Node depth_compare, u32 bias_offset,
                                std::vector<Node> aoffi,
                                std::optional<Tegra::Shader::Register> bindless_reg) {
-    const auto is_array = static_cast<bool>(array);
-    const auto is_shadow = static_cast<bool>(depth_compare);
+    const bool is_array = array != nullptr;
+    const bool is_shadow = depth_compare != nullptr;
     const bool is_bindless = bindless_reg.has_value();
 
-    UNIMPLEMENTED_IF_MSG((texture_type == TextureType::Texture3D && (is_array || is_shadow)) ||
-                             (texture_type == TextureType::TextureCube && is_array && is_shadow),
-                         "This method is not supported.");
+    UNIMPLEMENTED_IF(texture_type == TextureType::TextureCube && is_array && is_shadow);
+    ASSERT_MSG(texture_type != TextureType::Texture3D || is_array || is_shadow,
+               "Illegal texture type");
 
     const SamplerInfo info{texture_type, is_array, is_shadow, false};
-    Node index_var{};
+    Node index_var;
     const Sampler* sampler = is_bindless ? GetBindlessSampler(*bindless_reg, index_var, info)
                                          : GetSampler(instr.sampler, info);
-    Node4 values;
-    if (sampler == nullptr) {
-        for (u32 element = 0; element < values.size(); ++element) {
-            values[element] = Immediate(0);
-        }
-        return values;
+    if (!sampler) {
+        return {Immediate(0), Immediate(0), Immediate(0), Immediate(0)};
     }
 
     const bool lod_needed = process_mode == TextureProcessMode::LZ ||
                             process_mode == TextureProcessMode::LL ||
                             process_mode == TextureProcessMode::LLA;
-
-    // LOD selection (either via bias or explicit textureLod) not supported in GL for
-    // sampler2DArrayShadow and samplerCubeArrayShadow.
-    const bool gl_lod_supported =
-        !((texture_type == Tegra::Shader::TextureType::Texture2D && is_array && is_shadow) ||
-          (texture_type == Tegra::Shader::TextureType::TextureCube && is_array && is_shadow));
-
-    const OperationCode read_method =
-        (lod_needed && gl_lod_supported) ? OperationCode::TextureLod : OperationCode::Texture;
-
-    UNIMPLEMENTED_IF(process_mode != TextureProcessMode::None && !gl_lod_supported);
+    const OperationCode opcode = lod_needed ? OperationCode::TextureLod : OperationCode::Texture;
 
     Node bias;
     Node lod;
-    if (process_mode != TextureProcessMode::None && gl_lod_supported) {
-        switch (process_mode) {
-        case TextureProcessMode::LZ:
-            lod = Immediate(0.0f);
-            break;
-        case TextureProcessMode::LB:
-            // If present, lod or bias are always stored in the register
-            // indexed by the gpr20 field with an offset depending on the
-            // usage of the other registers
-            bias = GetRegister(instr.gpr20.Value() + bias_offset);
-            break;
-        case TextureProcessMode::LL:
-            lod = GetRegister(instr.gpr20.Value() + bias_offset);
-            break;
-        default:
-            UNIMPLEMENTED_MSG("Unimplemented process mode={}", static_cast<u32>(process_mode));
-            break;
-        }
+    switch (process_mode) {
+    case TextureProcessMode::None:
+        break;
+    case TextureProcessMode::LZ:
+        lod = Immediate(0.0f);
+        break;
+    case TextureProcessMode::LB:
+        // If present, lod or bias are always stored in the register indexed by the gpr20 field with
+        // an offset depending on the usage of the other registers.
+        bias = GetRegister(instr.gpr20.Value() + bias_offset);
+        break;
+    case TextureProcessMode::LL:
+        lod = GetRegister(instr.gpr20.Value() + bias_offset);
+        break;
+    default:
+        UNIMPLEMENTED_MSG("Unimplemented process mode={}", static_cast<u32>(process_mode));
+        break;
     }
 
+    Node4 values;
     for (u32 element = 0; element < values.size(); ++element) {
-        auto copy_coords = coords;
         MetaTexture meta{*sampler, array, depth_compare, aoffi,    {}, {}, bias,
                          lod,      {},    element,       index_var};
-        values[element] = Operation(read_method, meta, std::move(copy_coords));
+        values[element] = Operation(opcode, meta, coords);
     }
 
     return values;