5 files changed, 363 insertions, 163 deletions

diff --git a/src/video_core/renderer_opengl/gl_rasterizer.cpp b/src/video_core/renderer_opengl/gl_rasterizer.cpp
index 8a2db8e36..1af4268a4 100644
--- a/src/video_core/renderer_opengl/gl_rasterizer.cpp
+++ b/src/video_core/renderer_opengl/gl_rasterizer.cpp
@@ -496,7 +496,6 @@ void RasterizerOpenGL::Draw(bool is_indexed, bool is_instanced) {
     SyncCullMode();
     SyncPrimitiveRestart();
     SyncScissorTest();
-    SyncTransformFeedback();
     SyncPointState();
     SyncPolygonOffset();
     SyncAlphaTest();
@@ -569,7 +568,7 @@ void RasterizerOpenGL::Draw(bool is_indexed, bool is_instanced) {
         glTextureBarrier();
     }
 
-    ++num_queued_commands;
+    BeginTransformFeedback(primitive_mode);
 
     const GLuint base_instance = static_cast<GLuint>(gpu.regs.vb_base_instance);
     const GLsizei num_instances =
@@ -608,6 +607,10 @@ void RasterizerOpenGL::Draw(bool is_indexed, bool is_instanced) {
                                               num_instances, base_instance);
         }
     }
+
+    EndTransformFeedback();
+
+    ++num_queued_commands;
 }
 
 void RasterizerOpenGL::DispatchCompute(GPUVAddr code_addr) {
@@ -1290,11 +1293,6 @@ void RasterizerOpenGL::SyncScissorTest() {
     }
 }
 
-void RasterizerOpenGL::SyncTransformFeedback() {
-    const auto& regs = system.GPU().Maxwell3D().regs;
-    UNIMPLEMENTED_IF_MSG(regs.tfb_enabled != 0, "Transform feedbacks are not implemented");
-}
-
 void RasterizerOpenGL::SyncPointState() {
     auto& gpu = system.GPU().Maxwell3D();
     auto& flags = gpu.dirty.flags;
@@ -1370,4 +1368,62 @@ void RasterizerOpenGL::SyncFramebufferSRGB() {
     oglEnable(GL_FRAMEBUFFER_SRGB, gpu.regs.framebuffer_srgb);
 }
 
+void RasterizerOpenGL::BeginTransformFeedback(GLenum primitive_mode) {
+    const auto& regs = system.GPU().Maxwell3D().regs;
+    if (regs.tfb_enabled == 0) {
+        return;
+    }
+
+    UNIMPLEMENTED_IF(regs.IsShaderConfigEnabled(Maxwell::ShaderProgram::TesselationControl) ||
+                     regs.IsShaderConfigEnabled(Maxwell::ShaderProgram::TesselationEval) ||
+                     regs.IsShaderConfigEnabled(Maxwell::ShaderProgram::Geometry));
+
+    for (std::size_t index = 0; index < Maxwell::NumTransformFeedbackBuffers; ++index) {
+        const auto& binding = regs.tfb_bindings[index];
+        if (!binding.buffer_enable) {
+            if (enabled_transform_feedback_buffers[index]) {
+                glBindBufferRange(GL_TRANSFORM_FEEDBACK_BUFFER, static_cast<GLuint>(index), 0, 0,
+                                  0);
+            }
+            enabled_transform_feedback_buffers[index] = false;
+            continue;
+        }
+        enabled_transform_feedback_buffers[index] = true;
+
+        auto& tfb_buffer = transform_feedback_buffers[index];
+        tfb_buffer.Create();
+
+        const GLuint handle = tfb_buffer.handle;
+        const std::size_t size = binding.buffer_size;
+        glNamedBufferData(handle, static_cast<GLsizeiptr>(size), nullptr, GL_STREAM_COPY);
+        glBindBufferRange(GL_TRANSFORM_FEEDBACK_BUFFER, static_cast<GLuint>(index), handle, 0,
+                          static_cast<GLsizeiptr>(size));
+    }
+
+    glBeginTransformFeedback(GL_POINTS);
+}
+
+void RasterizerOpenGL::EndTransformFeedback() {
+    const auto& regs = system.GPU().Maxwell3D().regs;
+    if (regs.tfb_enabled == 0) {
+        return;
+    }
+
+    glEndTransformFeedback();
+
+    for (std::size_t index = 0; index < Maxwell::NumTransformFeedbackBuffers; ++index) {
+        const auto& binding = regs.tfb_bindings[index];
+        if (!binding.buffer_enable) {
+            continue;
+        }
+        UNIMPLEMENTED_IF(binding.buffer_offset != 0);
+
+        const GLuint handle = transform_feedback_buffers[index].handle;
+        const GPUVAddr gpu_addr = binding.Address();
+        const std::size_t size = binding.buffer_size;
+        const auto [dest_buffer, offset] = buffer_cache.UploadMemory(gpu_addr, size, 4, true);
+        glCopyNamedBufferSubData(handle, *dest_buffer, 0, offset, static_cast<GLsizeiptr>(size));
+    }
+}
+
 } // namespace OpenGL
diff --git a/src/video_core/renderer_opengl/gl_rasterizer.h b/src/video_core/renderer_opengl/gl_rasterizer.h
index e6424f5d2..2d3be2437 100644
--- a/src/video_core/renderer_opengl/gl_rasterizer.h
+++ b/src/video_core/renderer_opengl/gl_rasterizer.h
@@ -168,9 +168,6 @@ private:
     /// Syncs the scissor test state to match the guest state
     void SyncScissorTest();
 
-    /// Syncs the transform feedback state to match the guest state
-    void SyncTransformFeedback();
-
     /// Syncs the point state to match the guest state
     void SyncPointState();
 
@@ -192,6 +189,12 @@ private:
     /// Syncs the framebuffer sRGB state to match the guest state
     void SyncFramebufferSRGB();
 
+    /// Begin a transform feedback
+    void BeginTransformFeedback(GLenum primitive_mode);
+
+    /// End a transform feedback
+    void EndTransformFeedback();
+
     /// Check for extension that are not strictly required but are needed for correct emulation
     void CheckExtensions();
 
@@ -229,6 +232,11 @@ private:
     BindBuffersRangePushBuffer bind_ubo_pushbuffer{GL_UNIFORM_BUFFER};
     BindBuffersRangePushBuffer bind_ssbo_pushbuffer{GL_SHADER_STORAGE_BUFFER};
 
+    std::array<OGLBuffer, Tegra::Engines::Maxwell3D::Regs::NumTransformFeedbackBuffers>
+        transform_feedback_buffers;
+    std::bitset<Tegra::Engines::Maxwell3D::Regs::NumTransformFeedbackBuffers>
+        enabled_transform_feedback_buffers;
+
     /// Number of commands queued to the OpenGL driver. Reseted on flush.
     std::size_t num_queued_commands = 0;
 
diff --git a/src/video_core/renderer_opengl/gl_shader_decompiler.cpp b/src/video_core/renderer_opengl/gl_shader_decompiler.cpp
index 19d6f3dcb..849839fe3 100644
--- a/src/video_core/renderer_opengl/gl_shader_decompiler.cpp
+++ b/src/video_core/renderer_opengl/gl_shader_decompiler.cpp
@@ -23,6 +23,7 @@
 #include "video_core/shader/ast.h"
 #include "video_core/shader/node.h"
 #include "video_core/shader/shader_ir.h"
+#include "video_core/shader/transform_feedback.h"
 
 namespace OpenGL {
 
@@ -36,6 +37,7 @@ using Tegra::Shader::IpaInterpMode;
 using Tegra::Shader::IpaMode;
 using Tegra::Shader::IpaSampleMode;
 using Tegra::Shader::Register;
+using VideoCommon::Shader::BuildTransformFeedback;
 using VideoCommon::Shader::Registry;
 
 using namespace std::string_literals;
@@ -49,6 +51,11 @@ class ExprDecompiler;
 
 enum class Type { Void, Bool, Bool2, Float, Int, Uint, HalfFloat };
 
+constexpr std::array FLOAT_TYPES{"float", "vec2", "vec3", "vec4"};
+
+constexpr std::string_view INPUT_ATTRIBUTE_NAME = "in_attr";
+constexpr std::string_view OUTPUT_ATTRIBUTE_NAME = "out_attr";
+
 struct TextureOffset {};
 struct TextureDerivates {};
 using TextureArgument = std::pair<Type, Node>;
@@ -390,12 +397,22 @@ std::string FlowStackTopName(MetaStackClass stack) {
     return stage == ShaderType::Vertex;
 }
 
+struct GenericVaryingDescription {
+    std::string name;
+    u8 first_element = 0;
+    bool is_scalar = false;
+};
+
 class GLSLDecompiler final {
 public:
     explicit GLSLDecompiler(const Device& device, const ShaderIR& ir, const Registry& registry,
                             ShaderType stage, std::string_view identifier, std::string_view suffix)
         : device{device}, ir{ir}, registry{registry}, stage{stage},
-          identifier{identifier}, suffix{suffix}, header{ir.GetHeader()} {}
+          identifier{identifier}, suffix{suffix}, header{ir.GetHeader()} {
+        if (stage != ShaderType::Compute) {
+            transform_feedback = BuildTransformFeedback(registry.GetGraphicsInfo());
+        }
+    }
 
     void Decompile() {
         DeclareHeader();
@@ -403,17 +420,17 @@ public:
         DeclareGeometry();
         DeclareFragment();
         DeclareCompute();
-        DeclareRegisters();
-        DeclareCustomVariables();
-        DeclarePredicates();
-        DeclareLocalMemory();
-        DeclareInternalFlags();
         DeclareInputAttributes();
         DeclareOutputAttributes();
-        DeclareConstantBuffers();
-        DeclareGlobalMemory();
-        DeclareSamplers();
         DeclareImages();
+        DeclareSamplers();
+        DeclareGlobalMemory();
+        DeclareConstantBuffers();
+        DeclareLocalMemory();
+        DeclareRegisters();
+        DeclarePredicates();
+        DeclareInternalFlags();
+        DeclareCustomVariables();
         DeclarePhysicalAttributeReader();
 
         code.AddLine("void main() {{");
@@ -485,7 +502,7 @@ private:
         if (!identifier.empty()) {
             code.AddLine("// {}", identifier);
         }
-        code.AddLine("#version 430 core");
+        code.AddLine("#version 440 core");
         code.AddLine("#extension GL_ARB_separate_shader_objects : enable");
         if (device.HasShaderBallot()) {
             code.AddLine("#extension GL_ARB_shader_ballot : require");
@@ -570,7 +587,13 @@ private:
         code.AddLine("out gl_PerVertex {{");
         ++code.scope;
 
-        code.AddLine("vec4 gl_Position;");
+        auto pos_xfb = GetTransformFeedbackDecoration(Attribute::Index::Position);
+        if (!pos_xfb.empty()) {
+            pos_xfb = fmt::format("layout ({}) ", pos_xfb);
+        }
+        const char* pos_type =
+            FLOAT_TYPES.at(GetNumComponents(Attribute::Index::Position).value_or(4) - 1);
+        code.AddLine("{}{} gl_Position;", pos_xfb, pos_type);
 
         for (const auto attribute : ir.GetOutputAttributes()) {
             if (attribute == Attribute::Index::ClipDistances0123 ||
@@ -703,7 +726,7 @@ private:
     void DeclareInputAttribute(Attribute::Index index, bool skip_unused) {
         const u32 location{GetGenericAttributeIndex(index)};
 
-        std::string name{GetInputAttribute(index)};
+        std::string name{GetGenericInputAttribute(index)};
         if (stage == ShaderType::Geometry) {
             name = "gs_" + name + "[]";
         }
@@ -740,9 +763,59 @@ private:
         }
     }
 
+    std::optional<std::size_t> GetNumComponents(Attribute::Index index, u8 element = 0) const {
+        const u8 location = static_cast<u8>(static_cast<u32>(index) * 4 + element);
+        const auto it = transform_feedback.find(location);
+        if (it == transform_feedback.end()) {
+            return {};
+        }
+        return it->second.components;
+    }
+
+    std::string GetTransformFeedbackDecoration(Attribute::Index index, u8 element = 0) const {
+        const u8 location = static_cast<u8>(static_cast<u32>(index) * 4 + element);
+        const auto it = transform_feedback.find(location);
+        if (it == transform_feedback.end()) {
+            return {};
+        }
+
+        const VaryingTFB& tfb = it->second;
+        return fmt::format("xfb_buffer = {}, xfb_offset = {}, xfb_stride = {}", tfb.buffer,
+                           tfb.offset, tfb.stride);
+    }
+
     void DeclareOutputAttribute(Attribute::Index index) {
-        const u32 location{GetGenericAttributeIndex(index)};
-        code.AddLine("layout (location = {}) out vec4 {};", location, GetOutputAttribute(index));
+        static constexpr std::string_view swizzle = "xyzw";
+        u8 element = 0;
+        while (element < 4) {
+            auto xfb = GetTransformFeedbackDecoration(index, element);
+            if (!xfb.empty()) {
+                xfb = fmt::format(", {}", xfb);
+            }
+            const std::size_t remainder = 4 - element;
+            const std::size_t num_components = GetNumComponents(index, element).value_or(remainder);
+            const char* const type = FLOAT_TYPES.at(num_components - 1);
+
+            const u32 location = GetGenericAttributeIndex(index);
+
+            GenericVaryingDescription description;
+            description.first_element = static_cast<u8>(element);
+            description.is_scalar = num_components == 1;
+            description.name = AppendSuffix(location, OUTPUT_ATTRIBUTE_NAME);
+            if (element != 0 || num_components != 4) {
+                const std::string_view name_swizzle = swizzle.substr(element, num_components);
+                description.name = fmt::format("{}_{}", description.name, name_swizzle);
+            }
+            for (std::size_t i = 0; i < num_components; ++i) {
+                const u8 offset = static_cast<u8>(location * 4 + element + i);
+                varying_description.insert({offset, description});
+            }
+
+            code.AddLine("layout (location = {}, component = {}{}) out {} {};", location, element,
+                         xfb, type, description.name);
+
+            element = static_cast<u8>(static_cast<std::size_t>(element) + num_components);
+        }
     }
 
     void DeclareConstantBuffers() {
@@ -1095,7 +1168,7 @@ private:
             return {"0", Type::Int};
         default:
             if (IsGenericAttribute(attribute)) {
-                return {GeometryPass(GetInputAttribute(attribute)) + GetSwizzle(element),
+                return {GeometryPass(GetGenericInputAttribute(attribute)) + GetSwizzle(element),
                         Type::Float};
             }
             break;
@@ -1164,8 +1237,7 @@ private:
             return {{fmt::format("gl_ClipDistance[{}]", abuf->GetElement() + 4), Type::Float}};
         default:
             if (IsGenericAttribute(attribute)) {
-                return {
-                    {GetOutputAttribute(attribute) + GetSwizzle(abuf->GetElement()), Type::Float}};
+                return {{GetGenericOutputAttribute(attribute, abuf->GetElement()), Type::Float}};
             }
             UNIMPLEMENTED_MSG("Unhandled output attribute: {}", static_cast<u32>(attribute));
             return {};
@@ -1937,16 +2009,19 @@ private:
         expr += GetSampler(meta->sampler);
         expr += ", ";
 
-        expr += constructors.at(operation.GetOperandsCount() - 1);
+        expr += constructors.at(operation.GetOperandsCount() + (meta->array ? 1 : 0) - 1);
         expr += '(';
         for (std::size_t i = 0; i < count; ++i) {
-            expr += VisitOperand(operation, i).AsInt();
-            const std::size_t next = i + 1;
-            if (next == count)
-                expr += ')';
-            else if (next < count)
+            if (i > 0) {
                 expr += ", ";
+            }
+            expr += VisitOperand(operation, i).AsInt();
+        }
+        if (meta->array) {
+            expr += ", ";
+            expr += Visit(meta->array).AsInt();
         }
+        expr += ')';
 
         if (meta->lod && !meta->sampler.IsBuffer()) {
             expr += ", ";
@@ -2376,27 +2451,34 @@ private:
     static_assert(operation_decompilers.size() == static_cast<std::size_t>(OperationCode::Amount));
 
     std::string GetRegister(u32 index) const {
-        return GetDeclarationWithSuffix(index, "gpr");
+        return AppendSuffix(index, "gpr");
     }
 
     std::string GetCustomVariable(u32 index) const {
-        return GetDeclarationWithSuffix(index, "custom_var");
+        return AppendSuffix(index, "custom_var");
     }
 
     std::string GetPredicate(Tegra::Shader::Pred pred) const {
-        return GetDeclarationWithSuffix(static_cast<u32>(pred), "pred");
+        return AppendSuffix(static_cast<u32>(pred), "pred");
     }
 
-    std::string GetInputAttribute(Attribute::Index attribute) const {
-        return GetDeclarationWithSuffix(GetGenericAttributeIndex(attribute), "input_attr");
+    std::string GetGenericInputAttribute(Attribute::Index attribute) const {
+        return AppendSuffix(GetGenericAttributeIndex(attribute), INPUT_ATTRIBUTE_NAME);
     }
 
-    std::string GetOutputAttribute(Attribute::Index attribute) const {
-        return GetDeclarationWithSuffix(GetGenericAttributeIndex(attribute), "output_attr");
+    std::unordered_map<u8, GenericVaryingDescription> varying_description;
+
+    std::string GetGenericOutputAttribute(Attribute::Index attribute, std::size_t element) const {
+        const u8 offset = static_cast<u8>(GetGenericAttributeIndex(attribute) * 4 + element);
+        const auto& description = varying_description.at(offset);
+        if (description.is_scalar) {
+            return description.name;
+        }
+        return fmt::format("{}[{}]", description.name, element - description.first_element);
     }
 
     std::string GetConstBuffer(u32 index) const {
-        return GetDeclarationWithSuffix(index, "cbuf");
+        return AppendSuffix(index, "cbuf");
     }
 
     std::string GetGlobalMemory(const GlobalMemoryBase& descriptor) const {
@@ -2409,7 +2491,7 @@ private:
     }
 
     std::string GetConstBufferBlock(u32 index) const {
-        return GetDeclarationWithSuffix(index, "cbuf_block");
+        return AppendSuffix(index, "cbuf_block");
     }
 
     std::string GetLocalMemory() const {
@@ -2434,14 +2516,14 @@ private:
     }
 
     std::string GetSampler(const Sampler& sampler) const {
-        return GetDeclarationWithSuffix(static_cast<u32>(sampler.GetIndex()), "sampler");
+        return AppendSuffix(static_cast<u32>(sampler.GetIndex()), "sampler");
     }
 
     std::string GetImage(const Image& image) const {
-        return GetDeclarationWithSuffix(static_cast<u32>(image.GetIndex()), "image");
+        return AppendSuffix(static_cast<u32>(image.GetIndex()), "image");
     }
 
-    std::string GetDeclarationWithSuffix(u32 index, std::string_view name) const {
+    std::string AppendSuffix(u32 index, std::string_view name) const {
         if (suffix.empty()) {
             return fmt::format("{}{}", name, index);
         } else {
@@ -2477,6 +2559,7 @@ private:
     const std::string_view identifier;
     const std::string_view suffix;
     const Header header;
+    std::unordered_map<u8, VaryingTFB> transform_feedback;
 
     ShaderWriter code;
 
diff --git a/src/video_core/renderer_opengl/gl_texture_cache.cpp b/src/video_core/renderer_opengl/gl_texture_cache.cpp
index 2d3838a7a..f424e3000 100644
--- a/src/video_core/renderer_opengl/gl_texture_cache.cpp
+++ b/src/video_core/renderer_opengl/gl_texture_cache.cpp
@@ -53,6 +53,7 @@ constexpr std::array<FormatTuple, VideoCore::Surface::MaxPixelFormat> tex_format
     {GL_R8UI, GL_RED_INTEGER, GL_UNSIGNED_BYTE, false},                             // R8UI
     {GL_RGBA16F, GL_RGBA, GL_HALF_FLOAT, false},                                    // RGBA16F
     {GL_RGBA16, GL_RGBA, GL_UNSIGNED_SHORT, false},                                 // RGBA16U
+    {GL_RGBA16_SNORM, GL_RGBA, GL_SHORT, false},                                    // RGBA16S
     {GL_RGBA16UI, GL_RGBA_INTEGER, GL_UNSIGNED_SHORT, false},                       // RGBA16UI
     {GL_R11F_G11F_B10F, GL_RGB, GL_UNSIGNED_INT_10F_11F_11F_REV, false},            // R11FG11FB10F
     {GL_RGBA32UI, GL_RGBA_INTEGER, GL_UNSIGNED_INT, false},                         // RGBA32UI
diff --git a/src/video_core/renderer_opengl/renderer_opengl.cpp b/src/video_core/renderer_opengl/renderer_opengl.cpp
index 12333e8c9..fca5e3ec0 100644
--- a/src/video_core/renderer_opengl/renderer_opengl.cpp
+++ b/src/video_core/renderer_opengl/renderer_opengl.cpp
@@ -5,8 +5,11 @@
 #include <algorithm>
 #include <cstddef>
 #include <cstdlib>
+#include <cstring>
 #include <memory>
+
 #include <glad/glad.h>
+
 #include "common/assert.h"
 #include "common/logging/log.h"
 #include "common/microprofile.h"
@@ -25,6 +28,8 @@
 
 namespace OpenGL {
 
+namespace {
+
 // If the size of this is too small, it ends up creating a soft cap on FPS as the renderer will have
 // to wait on available presentation frames.
 constexpr std::size_t SWAP_CHAIN_SIZE = 3;
@@ -41,124 +46,6 @@ struct Frame {
     bool is_srgb{};                   /// Framebuffer is sRGB or RGB
 };
 
-/**
- * For smooth Vsync rendering, we want to always present the latest frame that the core generates,
- * but also make sure that rendering happens at the pace that the frontend dictates. This is a
- * helper class that the renderer uses to sync frames between the render thread and the presentation
- * thread
- */
-class FrameMailbox {
-public:
-    std::mutex swap_chain_lock;
-    std::condition_variable present_cv;
-    std::array<Frame, SWAP_CHAIN_SIZE> swap_chain{};
-    std::queue<Frame*> free_queue;
-    std::deque<Frame*> present_queue;
-    Frame* previous_frame{};
-
-    FrameMailbox() {
-        for (auto& frame : swap_chain) {
-            free_queue.push(&frame);
-        }
-    }
-
-    ~FrameMailbox() {
-        // lock the mutex and clear out the present and free_queues and notify any people who are
-        // blocked to prevent deadlock on shutdown
-        std::scoped_lock lock{swap_chain_lock};
-        std::queue<Frame*>().swap(free_queue);
-        present_queue.clear();
-        present_cv.notify_all();
-    }
-
-    void ReloadPresentFrame(Frame* frame, u32 height, u32 width) {
-        frame->present.Release();
-        frame->present.Create();
-        GLint previous_draw_fbo{};
-        glGetIntegerv(GL_DRAW_FRAMEBUFFER_BINDING, &previous_draw_fbo);
-        glBindFramebuffer(GL_FRAMEBUFFER, frame->present.handle);
-        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER,
-                                  frame->color.handle);
-        if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
-            LOG_CRITICAL(Render_OpenGL, "Failed to recreate present FBO!");
-        }
-        glBindFramebuffer(GL_DRAW_FRAMEBUFFER, previous_draw_fbo);
-        frame->color_reloaded = false;
-    }
-
-    void ReloadRenderFrame(Frame* frame, u32 width, u32 height) {
-        // Recreate the color texture attachment
-        frame->color.Release();
-        frame->color.Create();
-        const GLenum internal_format = frame->is_srgb ? GL_SRGB8 : GL_RGB8;
-        glNamedRenderbufferStorage(frame->color.handle, internal_format, width, height);
-
-        // Recreate the FBO for the render target
-        frame->render.Release();
-        frame->render.Create();
-        glBindFramebuffer(GL_FRAMEBUFFER, frame->render.handle);
-        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER,
-                                  frame->color.handle);
-        if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
-            LOG_CRITICAL(Render_OpenGL, "Failed to recreate render FBO!");
-        }
-
-        frame->width = width;
-        frame->height = height;
-        frame->color_reloaded = true;
-    }
-
-    Frame* GetRenderFrame() {
-        std::unique_lock lock{swap_chain_lock};
-
-        // If theres no free frames, we will reuse the oldest render frame
-        if (free_queue.empty()) {
-            auto frame = present_queue.back();
-            present_queue.pop_back();
-            return frame;
-        }
-
-        Frame* frame = free_queue.front();
-        free_queue.pop();
-        return frame;
-    }
-
-    void ReleaseRenderFrame(Frame* frame) {
-        std::unique_lock lock{swap_chain_lock};
-        present_queue.push_front(frame);
-        present_cv.notify_one();
-    }
-
-    Frame* TryGetPresentFrame(int timeout_ms) {
-        std::unique_lock lock{swap_chain_lock};
-        // wait for new entries in the present_queue
-        present_cv.wait_for(lock, std::chrono::milliseconds(timeout_ms),
-                            [&] { return !present_queue.empty(); });
-        if (present_queue.empty()) {
-            // timed out waiting for a frame to draw so return the previous frame
-            return previous_frame;
-        }
-
-        // free the previous frame and add it back to the free queue
-        if (previous_frame) {
-            free_queue.push(previous_frame);
-        }
-
-        // the newest entries are pushed to the front of the queue
-        Frame* frame = present_queue.front();
-        present_queue.pop_front();
-        // remove all old entries from the present queue and move them back to the free_queue
-        for (auto f : present_queue) {
-            free_queue.push(f);
-        }
-        present_queue.clear();
-        previous_frame = frame;
-        return frame;
-    }
-};
-
-namespace {
-
 constexpr char VERTEX_SHADER[] = R"(
 #version 430 core
 
@@ -211,6 +98,24 @@ struct ScreenRectVertex {
     std::array<GLfloat, 2> tex_coord;
 };
 
+/// Returns true if any debug tool is attached
+bool HasDebugTool() {
+    const bool nsight = std::getenv("NVTX_INJECTION64_PATH") || std::getenv("NSIGHT_LAUNCHED");
+    if (nsight) {
+        return true;
+    }
+
+    GLint num_extensions;
+    glGetIntegerv(GL_NUM_EXTENSIONS, &num_extensions);
+    for (GLuint index = 0; index < static_cast<GLuint>(num_extensions); ++index) {
+        const auto name = reinterpret_cast<const char*>(glGetStringi(GL_EXTENSIONS, index));
+        if (!std::strcmp(name, "GL_EXT_debug_tool")) {
+            return true;
+        }
+    }
+    return false;
+}
+
 /**
  * Defines a 1:1 pixel ortographic projection matrix with (0,0) on the top-left
  * corner and (width, height) on the lower-bottom.
@@ -294,6 +199,153 @@ void APIENTRY DebugHandler(GLenum source, GLenum type, GLuint id, GLenum severit
 
 } // Anonymous namespace
 
+/**
+ * For smooth Vsync rendering, we want to always present the latest frame that the core generates,
+ * but also make sure that rendering happens at the pace that the frontend dictates. This is a
+ * helper class that the renderer uses to sync frames between the render thread and the presentation
+ * thread
+ */
+class FrameMailbox {
+public:
+    std::mutex swap_chain_lock;
+    std::condition_variable present_cv;
+    std::array<Frame, SWAP_CHAIN_SIZE> swap_chain{};
+    std::queue<Frame*> free_queue;
+    std::deque<Frame*> present_queue;
+    Frame* previous_frame{};
+
+    FrameMailbox() : has_debug_tool{HasDebugTool()} {
+        for (auto& frame : swap_chain) {
+            free_queue.push(&frame);
+        }
+    }
+
+    ~FrameMailbox() {
+        // lock the mutex and clear out the present and free_queues and notify any people who are
+        // blocked to prevent deadlock on shutdown
+        std::scoped_lock lock{swap_chain_lock};
+        std::queue<Frame*>().swap(free_queue);
+        present_queue.clear();
+        present_cv.notify_all();
+    }
+
+    void ReloadPresentFrame(Frame* frame, u32 height, u32 width) {
+        frame->present.Release();
+        frame->present.Create();
+        GLint previous_draw_fbo{};
+        glGetIntegerv(GL_DRAW_FRAMEBUFFER_BINDING, &previous_draw_fbo);
+        glBindFramebuffer(GL_FRAMEBUFFER, frame->present.handle);
+        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER,
+                                  frame->color.handle);
+        if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
+            LOG_CRITICAL(Render_OpenGL, "Failed to recreate present FBO!");
+        }
+        glBindFramebuffer(GL_DRAW_FRAMEBUFFER, previous_draw_fbo);
+        frame->color_reloaded = false;
+    }
+
+    void ReloadRenderFrame(Frame* frame, u32 width, u32 height) {
+        // Recreate the color texture attachment
+        frame->color.Release();
+        frame->color.Create();
+        const GLenum internal_format = frame->is_srgb ? GL_SRGB8 : GL_RGB8;
+        glNamedRenderbufferStorage(frame->color.handle, internal_format, width, height);
+
+        // Recreate the FBO for the render target
+        frame->render.Release();
+        frame->render.Create();
+        glBindFramebuffer(GL_FRAMEBUFFER, frame->render.handle);
+        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER,
+                                  frame->color.handle);
+        if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
+            LOG_CRITICAL(Render_OpenGL, "Failed to recreate render FBO!");
+        }
+
+        frame->width = width;
+        frame->height = height;
+        frame->color_reloaded = true;
+    }
+
+    Frame* GetRenderFrame() {
+        std::unique_lock lock{swap_chain_lock};
+
+        // If theres no free frames, we will reuse the oldest render frame
+        if (free_queue.empty()) {
+            auto frame = present_queue.back();
+            present_queue.pop_back();
+            return frame;
+        }
+
+        Frame* frame = free_queue.front();
+        free_queue.pop();
+        return frame;
+    }
+
+    void ReleaseRenderFrame(Frame* frame) {
+        std::unique_lock lock{swap_chain_lock};
+        present_queue.push_front(frame);
+        present_cv.notify_one();
+
+        DebugNotifyNextFrame();
+    }
+
+    Frame* TryGetPresentFrame(int timeout_ms) {
+        DebugWaitForNextFrame();
+
+        std::unique_lock lock{swap_chain_lock};
+        // wait for new entries in the present_queue
+        present_cv.wait_for(lock, std::chrono::milliseconds(timeout_ms),
+                            [&] { return !present_queue.empty(); });
+        if (present_queue.empty()) {
+            // timed out waiting for a frame to draw so return the previous frame
+            return previous_frame;
+        }
+
+        // free the previous frame and add it back to the free queue
+        if (previous_frame) {
+            free_queue.push(previous_frame);
+        }
+
+        // the newest entries are pushed to the front of the queue
+        Frame* frame = present_queue.front();
+        present_queue.pop_front();
+        // remove all old entries from the present queue and move them back to the free_queue
+        for (auto f : present_queue) {
+            free_queue.push(f);
+        }
+        present_queue.clear();
+        previous_frame = frame;
+        return frame;
+    }
+
+private:
+    std::mutex debug_synch_mutex;
+    std::condition_variable debug_synch_condition;
+    std::atomic_int frame_for_debug{};
+    const bool has_debug_tool; // When true, using a GPU debugger, so keep frames in lock-step
+
+    /// Signal that a new frame is available (called from GPU thread)
+    void DebugNotifyNextFrame() {
+        if (!has_debug_tool) {
+            return;
+        }
+        frame_for_debug++;
+        std::lock_guard lock{debug_synch_mutex};
+        debug_synch_condition.notify_one();
+    }
+
+    /// Wait for a new frame to be available (called from presentation thread)
+    void DebugWaitForNextFrame() {
+        if (!has_debug_tool) {
+            return;
+        }
+        const int last_frame = frame_for_debug;
+        std::unique_lock lock{debug_synch_mutex};
+        debug_synch_condition.wait(lock,
+                                   [this, last_frame] { return frame_for_debug > last_frame; });
+    }
+};
+
 RendererOpenGL::RendererOpenGL(Core::Frontend::EmuWindow& emu_window, Core::System& system)
     : VideoCore::RendererBase{emu_window}, emu_window{emu_window}, system{system},
       frame_mailbox{std::make_unique<FrameMailbox>()} {}