video_core: Generate mipmap texture by drawing

src/shader_recompiler/backend/spirv/emit_spirv.h

@@ -23,8 +23,12 @@ struct RescalingLayout {
     alignas(16) std::array<u32, NUM_IMAGE_SCALING_WORDS> rescaling_images;
     u32 down_factor;
 };
+struct RenderAreaLayout {
+    std::array<f32, 4> render_area;
+};
 constexpr u32 RESCALING_LAYOUT_WORDS_OFFSET = offsetof(RescalingLayout, rescaling_textures);
 constexpr u32 RESCALING_LAYOUT_DOWN_FACTOR_OFFSET = offsetof(RescalingLayout, down_factor);
+constexpr u32 RENDERAREA_LAYOUT_OFFSET = offsetof(RenderAreaLayout, render_area);
 
 [[nodiscard]] std::vector<u32> EmitSPIRV(const Profile& profile, const RuntimeInfo& runtime_info,
                                          IR::Program& program, Bindings& bindings);

src/shader_recompiler/backend/spirv/emit_spirv_context_get_set.cpp

@@ -353,7 +353,6 @@ Id EmitGetAttribute(EmitContext& ctx, IR::Attribute attr, Id vertex) {
     case IR::Attribute::TessellationEvaluationPointV:
         return ctx.OpLoad(ctx.F32[1],
                           ctx.OpAccessChain(ctx.input_f32, ctx.tess_coord, ctx.Const(1U)));
-
     default:
         throw NotImplementedException("Read attribute {}", attr);
     }
@@ -537,6 +536,17 @@ Id EmitResolutionDownFactor(EmitContext& ctx) {
     }
 }
 
+Id EmitRenderArea(EmitContext& ctx) {
+    if (ctx.profile.unified_descriptor_binding) {
+        const Id pointer_type{ctx.TypePointer(spv::StorageClass::PushConstant, ctx.F32[4])};
+        const Id index{ctx.Const(ctx.render_are_member_index)};
+        const Id pointer{ctx.OpAccessChain(pointer_type, ctx.render_area_push_constant, index)};
+        return ctx.OpLoad(ctx.F32[4], pointer);
+    } else {
+        throw NotImplementedException("SPIR-V Instruction");
+    }
+}
+
 Id EmitLoadLocal(EmitContext& ctx, Id word_offset) {
     const Id pointer{ctx.OpAccessChain(ctx.private_u32, ctx.local_memory, word_offset)};
     return ctx.OpLoad(ctx.U32[1], pointer);

src/shader_recompiler/backend/spirv/emit_spirv_instructions.h

@@ -76,6 +76,7 @@ Id EmitSampleId(EmitContext& ctx);
 Id EmitIsHelperInvocation(EmitContext& ctx);
 Id EmitYDirection(EmitContext& ctx);
 Id EmitResolutionDownFactor(EmitContext& ctx);
+Id EmitRenderArea(EmitContext& ctx);
 Id EmitLoadLocal(EmitContext& ctx, Id word_offset);
 void EmitWriteLocal(EmitContext& ctx, Id word_offset, Id value);
 Id EmitUndefU1(EmitContext& ctx);

src/shader_recompiler/backend/spirv/spirv_emit_context.cpp

@@ -473,6 +473,7 @@ EmitContext::EmitContext(const Profile& profile_, const RuntimeInfo& runtime_inf
     DefineAttributeMemAccess(program.info);
     DefineGlobalMemoryFunctions(program.info);
     DefineRescalingInput(program.info);
+    DefineRenderArea(program.info);
 }
 
 EmitContext::~EmitContext() = default;
@@ -982,6 +983,36 @@ void EmitContext::DefineRescalingInputUniformConstant() {
     }
 }
 
+void EmitContext::DefineRenderArea(const Info& info) {
+    if (!info.uses_render_area) {
+        return;
+    }
+
+    if (profile.unified_descriptor_binding) {
+        boost::container::static_vector<Id, 1> members{};
+        u32 member_index{0};
+
+        members.push_back(F32[4]);
+        render_are_member_index = member_index++;
+
+        const Id push_constant_struct{TypeStruct(std::span(members.data(), members.size()))};
+        Decorate(push_constant_struct, spv::Decoration::Block);
+        Name(push_constant_struct, "RenderAreaInfo");
+
+        MemberDecorate(push_constant_struct, render_are_member_index, spv::Decoration::Offset, 0);
+        MemberName(push_constant_struct, render_are_member_index, "render_area");
+
+        const Id pointer_type{TypePointer(spv::StorageClass::PushConstant, push_constant_struct)};
+        render_area_push_constant =
+            AddGlobalVariable(pointer_type, spv::StorageClass::PushConstant);
+        Name(render_area_push_constant, "render_area_push_constants");
+
+        if (profile.supported_spirv >= 0x00010400) {
+            interfaces.push_back(render_area_push_constant);
+        }
+    }
+}
+
 void EmitContext::DefineConstantBuffers(const Info& info, u32& binding) {
     if (info.constant_buffer_descriptors.empty()) {
         return;

src/shader_recompiler/backend/spirv/spirv_emit_context.h

@@ -243,6 +243,9 @@ public:
     u32 texture_rescaling_index{};
     u32 image_rescaling_index{};
 
+    Id render_area_push_constant{};
+    u32 render_are_member_index{};
+
     Id local_memory{};
 
     Id shared_memory_u8{};
@@ -318,6 +321,7 @@ private:
     void DefineRescalingInput(const Info& info);
     void DefineRescalingInputPushConstant();
     void DefineRescalingInputUniformConstant();
+    void DefineRenderArea(const Info& info);
 
     void DefineInputs(const IR::Program& program);
     void DefineOutputs(const IR::Program& program);