[vk] Correct polygon draw topology mapping for line and point modes (#2834)

Co-authored-by: Ribbit <ribbit@placeholder.com>
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/2834
Reviewed-by: MaranBr <maranbr@eden-emu.dev>
Reviewed-by: crueter <crueter@eden-emu.dev>
Co-authored-by: Ribbit <ribbit@eden-emu.dev>
Co-committed-by: Ribbit <ribbit@eden-emu.dev>

8 files changed, 296 insertions, 49 deletions

diff --git a/src/video_core/buffer_cache/buffer_cache.h b/src/video_core/buffer_cache/buffer_cache.h
index 39c56fb33f..ddd940c6d2 100644
--- a/src/video_core/buffer_cache/buffer_cache.h
+++ b/src/video_core/buffer_cache/buffer_cache.h
@@ -7,6 +7,7 @@
 #pragma once
 
 #include <algorithm>
+#include <cstring>
 #include <memory>
 #include <numeric>
 
@@ -15,6 +16,8 @@
 #include "video_core/guest_memory.h"
 #include "video_core/host1x/gpu_device_memory_manager.h"
 #include "video_core/texture_cache/util.h"
+#include "video_core/polygon_mode_utils.h"
+#include "video_core/renderer_vulkan/line_loop_utils.h"
 
 namespace VideoCommon {
 
@@ -353,14 +356,37 @@ void BufferCache<P>::UpdateComputeBuffers() {
 
 template <class P>
 void BufferCache<P>::BindHostGeometryBuffers(bool is_indexed) {
+    const auto& draw_state = maxwell3d->draw_manager->GetDrawState();
     if (is_indexed) {
         BindHostIndexBuffer();
-    } else if constexpr (!HAS_FULL_INDEX_AND_PRIMITIVE_SUPPORT) {
-        const auto& draw_state = maxwell3d->draw_manager->GetDrawState();
-        if (draw_state.topology == Maxwell::PrimitiveTopology::Quads ||
-            draw_state.topology == Maxwell::PrimitiveTopology::QuadStrip) {
-            runtime.BindQuadIndexBuffer(draw_state.topology, draw_state.vertex_buffer.first,
-                                        draw_state.vertex_buffer.count);
+    } else {
+        if constexpr (!P::IS_OPENGL) {
+            const auto polygon_mode = VideoCore::EffectivePolygonMode(maxwell3d->regs);
+            if (draw_state.topology == Maxwell::PrimitiveTopology::Polygon &&
+                polygon_mode == Maxwell::PolygonMode::Line && draw_state.vertex_buffer.count > 1) {
+                const u32 vertex_count = draw_state.vertex_buffer.count;
+                const u32 generated_count = vertex_count + 1;
+                const bool use_u16 = vertex_count <= 0x10000;
+                const u32 element_size = use_u16 ? sizeof(u16) : sizeof(u32);
+                auto staging = runtime.UploadStagingBuffer(
+                    static_cast<size_t>(generated_count) * element_size);
+                std::span<u8> dst_span{staging.mapped_span.data(),
+                                       generated_count * static_cast<size_t>(element_size)};
+                Vulkan::LineLoop::GenerateSequentialWithClosureRaw(dst_span, element_size);
+                const auto synthetic_format = use_u16 ? Maxwell::IndexFormat::UnsignedShort
+                                                      : Maxwell::IndexFormat::UnsignedInt;
+                runtime.BindIndexBuffer(draw_state.topology, synthetic_format,
+                                        draw_state.vertex_buffer.first, generated_count,
+                                        staging.buffer, static_cast<u32>(staging.offset),
+                                        generated_count * element_size);
+            }
+        }
+        if constexpr (!HAS_FULL_INDEX_AND_PRIMITIVE_SUPPORT) {
+            if (draw_state.topology == Maxwell::PrimitiveTopology::Quads ||
+                draw_state.topology == Maxwell::PrimitiveTopology::QuadStrip) {
+                runtime.BindQuadIndexBuffer(draw_state.topology, draw_state.vertex_buffer.first,
+                                            draw_state.vertex_buffer.count);
+            }
         }
     }
     BindHostVertexBuffers();
@@ -689,6 +715,44 @@ void BufferCache<P>::BindHostIndexBuffer() {
     const u32 offset = buffer.Offset(channel_state->index_buffer.device_addr);
     const u32 size = channel_state->index_buffer.size;
     const auto& draw_state = maxwell3d->draw_manager->GetDrawState();
+    if constexpr (!P::IS_OPENGL) {
+        const auto polygon_mode = VideoCore::EffectivePolygonMode(maxwell3d->regs);
+        const bool polygon_line =
+            draw_state.topology == Maxwell::PrimitiveTopology::Polygon &&
+            polygon_mode == Maxwell::PolygonMode::Line;
+        if (polygon_line && draw_state.index_buffer.count > 1) {
+            const u32 element_size = draw_state.index_buffer.FormatSizeInBytes();
+            const size_t src_bytes = static_cast<size_t>(draw_state.index_buffer.count) * element_size;
+            const size_t total_bytes = src_bytes + element_size;
+            auto staging = runtime.UploadStagingBuffer(total_bytes);
+            std::span<u8> dst_span{staging.mapped_span.data(), total_bytes};
+            std::span<const u8> src_span;
+            if (!draw_state.inline_index_draw_indexes.empty()) {
+                const u8* const src =
+                    draw_state.inline_index_draw_indexes.data() +
+                    static_cast<size_t>(draw_state.index_buffer.first) * element_size;
+                src_span = {src, src_bytes};
+            } else if (const u8* const cpu_base =
+                           device_memory.GetPointer<u8>(channel_state->index_buffer.device_addr)) {
+                const u8* const src = cpu_base +
+                                      static_cast<size_t>(draw_state.index_buffer.first) * element_size;
+                src_span = {src, src_bytes};
+            } else {
+                const DAddr src_addr =
+                    channel_state->index_buffer.device_addr +
+                    static_cast<DAddr>(draw_state.index_buffer.first) * element_size;
+                device_memory.ReadBlockUnsafe(src_addr, dst_span.data(), src_bytes);
+                src_span = {dst_span.data(), src_bytes};
+            }
+            Vulkan::LineLoop::CopyWithClosureRaw(dst_span, src_span, element_size);
+            buffer.MarkUsage(offset, size);
+            runtime.BindIndexBuffer(draw_state.topology, draw_state.index_buffer.format,
+                                    draw_state.index_buffer.first, draw_state.index_buffer.count + 1,
+                                    staging.buffer, static_cast<u32>(staging.offset),
+                                    static_cast<u32>(total_bytes));
+            return;
+        }
+    }
     if (!draw_state.inline_index_draw_indexes.empty()) [[unlikely]] {
         if constexpr (USE_MEMORY_MAPS_FOR_UPLOADS) {
             auto upload_staging = runtime.UploadStagingBuffer(size);
diff --git a/src/video_core/polygon_mode_utils.h b/src/video_core/polygon_mode_utils.h
new file mode 100644
index 0000000000..c44570693e
--- /dev/null
+++ b/src/video_core/polygon_mode_utils.h
@@ -0,0 +1,46 @@
+// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#pragma once
+
+#include "video_core/engines/maxwell_3d.h"
+
+namespace VideoCore {
+
+inline Tegra::Engines::Maxwell3D::Regs::PolygonMode EffectivePolygonMode(
+    const Tegra::Engines::Maxwell3D::Regs& regs) {
+    using Maxwell = Tegra::Engines::Maxwell3D::Regs;
+
+    const bool cull_enabled = regs.gl_cull_test_enabled != 0;
+    const auto cull_face = regs.gl_cull_face;
+    const bool cull_front = cull_enabled && (cull_face == Maxwell::CullFace::Front ||
+                                             cull_face == Maxwell::CullFace::FrontAndBack);
+    const bool cull_back = cull_enabled && (cull_face == Maxwell::CullFace::Back ||
+                                            cull_face == Maxwell::CullFace::FrontAndBack);
+
+    const bool render_front = !cull_front;
+    const bool render_back = !cull_back;
+
+    const auto front_mode = regs.polygon_mode_front;
+    const auto back_mode = regs.polygon_mode_back;
+
+    if (render_front && render_back && front_mode != back_mode) {
+        if (front_mode == Maxwell::PolygonMode::Line || back_mode == Maxwell::PolygonMode::Line) {
+            return Maxwell::PolygonMode::Line;
+        }
+        if (front_mode == Maxwell::PolygonMode::Point || back_mode == Maxwell::PolygonMode::Point) {
+            return Maxwell::PolygonMode::Point;
+        }
+    }
+
+    if (render_front) {
+        return front_mode;
+    }
+    if (render_back) {
+        return back_mode;
+    }
+    return front_mode;
+}
+
+} // namespace VideoCore
+
diff --git a/src/video_core/renderer_vulkan/fixed_pipeline_state.cpp b/src/video_core/renderer_vulkan/fixed_pipeline_state.cpp
index ff2dd90aff..453a3d942b 100644
--- a/src/video_core/renderer_vulkan/fixed_pipeline_state.cpp
+++ b/src/video_core/renderer_vulkan/fixed_pipeline_state.cpp
@@ -14,6 +14,7 @@
 #include "video_core/engines/draw_manager.h"
 #include "video_core/renderer_vulkan/fixed_pipeline_state.h"
 #include "video_core/renderer_vulkan/vk_state_tracker.h"
+#include "video_core/polygon_mode_utils.h"
 
 namespace Vulkan {
 namespace {
@@ -64,7 +65,7 @@ void FixedPipelineState::Refresh(Tegra::Engines::Maxwell3D& maxwell3d, DynamicFe
     dynamic_vertex_input.Assign(features.has_dynamic_vertex_input ? 1 : 0);
     xfb_enabled.Assign(regs.transform_feedback_enabled != 0);
     ndc_minus_one_to_one.Assign(regs.depth_mode == Maxwell::DepthMode::MinusOneToOne ? 1 : 0);
-    polygon_mode.Assign(PackPolygonMode(regs.polygon_mode_front));
+    polygon_mode.Assign(PackPolygonMode(VideoCore::EffectivePolygonMode(regs)));
     tessellation_primitive.Assign(static_cast<u32>(regs.tessellation.params.domain_type.Value()));
     tessellation_spacing.Assign(static_cast<u32>(regs.tessellation.params.spacing.Value()));
     tessellation_clockwise.Assign(regs.tessellation.params.output_primitives.Value() ==
diff --git a/src/video_core/renderer_vulkan/line_loop_utils.h b/src/video_core/renderer_vulkan/line_loop_utils.h
new file mode 100644
index 0000000000..71f4229d11
--- /dev/null
+++ b/src/video_core/renderer_vulkan/line_loop_utils.h
@@ -0,0 +1,68 @@
+// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#pragma once
+
+#include <algorithm>
+#include <cstring>
+#include <span>
+
+#include "common/assert.h"
+#include "common/common_types.h"
+
+namespace Vulkan::LineLoop {
+
+inline void CopyWithClosureRaw(std::span<u8> dst, std::span<const u8> src, size_t element_size) {
+    ASSERT_MSG(dst.size() == src.size() + element_size, "Invalid line loop copy sizes");
+    if (src.empty()) {
+        if (!dst.empty()) {
+            std::fill(dst.begin(), dst.end(), u8{0});
+        }
+        return;
+    }
+    std::memcpy(dst.data(), src.data(), src.size());
+    std::memcpy(dst.data() + src.size(), src.data(), element_size);
+}
+
+inline void GenerateSequentialWithClosureRaw(std::span<u8> dst, size_t element_size,
+                                             u64 start_value = 0) {
+    if (dst.empty()) {
+        return;
+    }
+    const size_t last = dst.size() - element_size;
+    size_t offset = 0;
+    u64 value = start_value;
+    while (offset < last) {
+        std::memcpy(dst.data() + offset, &value, element_size);
+        offset += element_size;
+        ++value;
+    }
+    std::memcpy(dst.data() + offset, &start_value, element_size);
+}
+
+template <typename T>
+inline void CopyWithClosure(std::span<T> dst, std::span<const T> src) {
+    ASSERT_MSG(dst.size() == src.size() + 1, "Invalid destination size for line loop copy");
+    if (src.empty()) {
+        if (!dst.empty()) {
+            dst.front() = {};
+        }
+        return;
+    }
+    std::copy(src.begin(), src.end(), dst.begin());
+    dst.back() = src.front();
+}
+
+template <typename T>
+inline void GenerateSequentialWithClosure(std::span<T> dst, T start_value = {}) {
+    if (dst.empty()) {
+        return;
+    }
+    const size_t last = dst.size() - 1;
+    for (size_t i = 0; i < last; ++i) {
+        dst[i] = static_cast<T>(start_value + static_cast<T>(i));
+    }
+    dst.back() = start_value;
+}
+
+} // namespace Vulkan::LineLoop
diff --git a/src/video_core/renderer_vulkan/maxwell_to_vk.cpp b/src/video_core/renderer_vulkan/maxwell_to_vk.cpp
index a08f2f67f9..a7a878f18c 100644
--- a/src/video_core/renderer_vulkan/maxwell_to_vk.cpp
+++ b/src/video_core/renderer_vulkan/maxwell_to_vk.cpp
@@ -1,3 +1,6 @@
+// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
 // SPDX-FileCopyrightText: Copyright 2019 yuzu Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -326,44 +329,9 @@ VkShaderStageFlagBits ShaderStage(Shader::Stage stage) {
 }
 
 VkPrimitiveTopology PrimitiveTopology([[maybe_unused]] const Device& device,
-                                      Maxwell::PrimitiveTopology topology) {
-    switch (topology) {
-    case Maxwell::PrimitiveTopology::Points:
-        return VK_PRIMITIVE_TOPOLOGY_POINT_LIST;
-    case Maxwell::PrimitiveTopology::Lines:
-        return VK_PRIMITIVE_TOPOLOGY_LINE_LIST;
-    case Maxwell::PrimitiveTopology::LineLoop:
-        return VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST;
-    case Maxwell::PrimitiveTopology::LineStrip:
-        return VK_PRIMITIVE_TOPOLOGY_LINE_STRIP;
-    case Maxwell::PrimitiveTopology::Triangles:
-        return VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST;
-    case Maxwell::PrimitiveTopology::TriangleStrip:
-        return VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP;
-    case Maxwell::PrimitiveTopology::TriangleFan:
-        return VK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN;
-    case Maxwell::PrimitiveTopology::LinesAdjacency:
-        return VK_PRIMITIVE_TOPOLOGY_LINE_LIST_WITH_ADJACENCY;
-    case Maxwell::PrimitiveTopology::LineStripAdjacency:
-        return VK_PRIMITIVE_TOPOLOGY_LINE_STRIP_WITH_ADJACENCY;
-    case Maxwell::PrimitiveTopology::TrianglesAdjacency:
-        return VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST_WITH_ADJACENCY;
-    case Maxwell::PrimitiveTopology::TriangleStripAdjacency:
-        return VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP_WITH_ADJACENCY;
-    case Maxwell::PrimitiveTopology::Quads:
-    case Maxwell::PrimitiveTopology::QuadStrip:
-        // TODO: Use VK_PRIMITIVE_TOPOLOGY_QUAD_LIST_EXT/VK_PRIMITIVE_TOPOLOGY_QUAD_STRIP_EXT
-        // whenever it releases
-        return VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST;
-    case Maxwell::PrimitiveTopology::Patches:
-        return VK_PRIMITIVE_TOPOLOGY_PATCH_LIST;
-    case Maxwell::PrimitiveTopology::Polygon:
-        LOG_WARNING(Render_Vulkan, "Draw mode is Polygon with a polygon mode of lines should be a "
-                                   "single body and not a bunch of triangles.");
-        return VK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN;
-    }
-    UNIMPLEMENTED_MSG("Unimplemented topology={}", topology);
-    return {};
+                                      Maxwell::PrimitiveTopology topology,
+                                      Maxwell::PolygonMode polygon_mode) {
+    return detail::PrimitiveTopologyNoDevice(topology, polygon_mode);
 }
 
 VkFormat VertexFormat(const Device& device, Maxwell::VertexAttribute::Type type,
diff --git a/src/video_core/renderer_vulkan/maxwell_to_vk.h b/src/video_core/renderer_vulkan/maxwell_to_vk.h
index 6f65502d61..22108a3769 100644
--- a/src/video_core/renderer_vulkan/maxwell_to_vk.h
+++ b/src/video_core/renderer_vulkan/maxwell_to_vk.h
@@ -1,3 +1,6 @@
+// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
 // SPDX-FileCopyrightText: Copyright 2019 yuzu Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -15,6 +18,52 @@ namespace Vulkan::MaxwellToVK {
 using Maxwell = Tegra::Engines::Maxwell3D::Regs;
 using PixelFormat = VideoCore::Surface::PixelFormat;
 
+namespace detail {
+constexpr VkPrimitiveTopology PrimitiveTopologyNoDevice(Maxwell::PrimitiveTopology topology,
+                                                        Maxwell::PolygonMode polygon_mode) {
+    switch (topology) {
+    case Maxwell::PrimitiveTopology::Points:
+        return VK_PRIMITIVE_TOPOLOGY_POINT_LIST;
+    case Maxwell::PrimitiveTopology::Lines:
+        return VK_PRIMITIVE_TOPOLOGY_LINE_LIST;
+    case Maxwell::PrimitiveTopology::LineLoop:
+        return VK_PRIMITIVE_TOPOLOGY_LINE_STRIP;
+    case Maxwell::PrimitiveTopology::LineStrip:
+        return VK_PRIMITIVE_TOPOLOGY_LINE_STRIP;
+    case Maxwell::PrimitiveTopology::Triangles:
+        return VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST;
+    case Maxwell::PrimitiveTopology::TriangleStrip:
+        return VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP;
+    case Maxwell::PrimitiveTopology::TriangleFan:
+        return VK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN;
+    case Maxwell::PrimitiveTopology::LinesAdjacency:
+        return VK_PRIMITIVE_TOPOLOGY_LINE_LIST_WITH_ADJACENCY;
+    case Maxwell::PrimitiveTopology::LineStripAdjacency:
+        return VK_PRIMITIVE_TOPOLOGY_LINE_STRIP_WITH_ADJACENCY;
+    case Maxwell::PrimitiveTopology::TrianglesAdjacency:
+        return VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST_WITH_ADJACENCY;
+    case Maxwell::PrimitiveTopology::TriangleStripAdjacency:
+        return VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP_WITH_ADJACENCY;
+    case Maxwell::PrimitiveTopology::Quads:
+    case Maxwell::PrimitiveTopology::QuadStrip:
+        return VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST;
+    case Maxwell::PrimitiveTopology::Patches:
+        return VK_PRIMITIVE_TOPOLOGY_PATCH_LIST;
+    case Maxwell::PrimitiveTopology::Polygon:
+        switch (polygon_mode) {
+        case Maxwell::PolygonMode::Fill:
+            return VK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN;
+        case Maxwell::PolygonMode::Line:
+            return VK_PRIMITIVE_TOPOLOGY_LINE_STRIP;
+        case Maxwell::PolygonMode::Point:
+            return VK_PRIMITIVE_TOPOLOGY_POINT_LIST;
+        }
+        break;
+    }
+    return VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST;
+}
+} // namespace detail
+
 namespace Sampler {
 
 VkFilter Filter(Tegra::Texture::TextureFilter filter);
@@ -46,7 +95,8 @@ struct FormatInfo {
 
 VkShaderStageFlagBits ShaderStage(Shader::Stage stage);
 
-VkPrimitiveTopology PrimitiveTopology(const Device& device, Maxwell::PrimitiveTopology topology);
+VkPrimitiveTopology PrimitiveTopology(const Device& device, Maxwell::PrimitiveTopology topology,
+                                      Maxwell::PolygonMode polygon_mode);
 
 VkFormat VertexFormat(const Device& device, Maxwell::VertexAttribute::Type type,
                       Maxwell::VertexAttribute::Size size);
diff --git a/src/video_core/renderer_vulkan/vk_graphics_pipeline.cpp b/src/video_core/renderer_vulkan/vk_graphics_pipeline.cpp
index 745389213e..13ed1b585e 100644
--- a/src/video_core/renderer_vulkan/vk_graphics_pipeline.cpp
+++ b/src/video_core/renderer_vulkan/vk_graphics_pipeline.cpp
@@ -7,6 +7,7 @@
 #include <algorithm>
 #include <iostream>
 #include <span>
+#include <string_view>
 
 #include <boost/container/small_vector.hpp>
 #include <boost/container/static_vector.hpp>
@@ -22,6 +23,7 @@
 #include "video_core/renderer_vulkan/vk_scheduler.h"
 #include "video_core/renderer_vulkan/vk_texture_cache.h"
 #include "video_core/renderer_vulkan/vk_update_descriptor.h"
+#include "video_core/polygon_mode_utils.h"
 #include "video_core/shader_notify.h"
 #include "video_core/texture_cache/texture_cache.h"
 #include "video_core/vulkan_common/vulkan_device.h"
@@ -614,7 +616,10 @@ void GraphicsPipeline::MakePipeline(VkRenderPass render_pass) {
         vertex_input_ci.pNext = &input_divisor_ci;
     }
     const bool has_tess_stages = spv_modules[1] || spv_modules[2];
-    auto input_assembly_topology = MaxwellToVK::PrimitiveTopology(device, key.state.topology);
+    const auto polygon_mode =
+        FixedPipelineState::UnpackPolygonMode(key.state.polygon_mode.Value());
+    auto input_assembly_topology =
+        MaxwellToVK::PrimitiveTopology(device, key.state.topology, polygon_mode);
     if (input_assembly_topology == VK_PRIMITIVE_TOPOLOGY_PATCH_LIST) {
         if (!has_tess_stages) {
             LOG_WARNING(Render_Vulkan, "Patch topology used without tessellation, using points");
@@ -629,6 +634,33 @@ void GraphicsPipeline::MakePipeline(VkRenderPass render_pass) {
             input_assembly_topology = VK_PRIMITIVE_TOPOLOGY_PATCH_LIST;
         }
     }
+    if (key.state.topology == Maxwell::PrimitiveTopology::Polygon) {
+        const auto polygon_mode_name = [polygon_mode]() -> std::string_view {
+            switch (polygon_mode) {
+            case Maxwell::PolygonMode::Fill:
+                return "Fill";
+            case Maxwell::PolygonMode::Line:
+                return "Line";
+            case Maxwell::PolygonMode::Point:
+                return "Point";
+            }
+            return "Unknown";
+        }();
+        const auto vk_topology_name = [input_assembly_topology]() -> std::string_view {
+            switch (input_assembly_topology) {
+            case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN:
+                return "TriangleFan";
+            case VK_PRIMITIVE_TOPOLOGY_LINE_STRIP:
+                return "LineStrip";
+            case VK_PRIMITIVE_TOPOLOGY_POINT_LIST:
+                return "PointList";
+            default:
+                return "Unexpected";
+            }
+        }();
+        LOG_DEBUG(Render_Vulkan, "Polygon primitive in {} mode mapped to {}", polygon_mode_name,
+                  vk_topology_name);
+    }
     const VkPipelineInputAssemblyStateCreateInfo input_assembly_ci{
         .sType = VK_STRUCTURE_TYPE_PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO,
         .pNext = nullptr,
diff --git a/src/video_core/renderer_vulkan/vk_rasterizer.cpp b/src/video_core/renderer_vulkan/vk_rasterizer.cpp
index 70ca9583f9..6bad5eca0b 100644
--- a/src/video_core/renderer_vulkan/vk_rasterizer.cpp
+++ b/src/video_core/renderer_vulkan/vk_rasterizer.cpp
@@ -37,6 +37,7 @@
 #include "video_core/renderer_vulkan/vk_update_descriptor.h"
 #include "video_core/shader_cache.h"
 #include "video_core/texture_cache/texture_cache_base.h"
+#include "video_core/polygon_mode_utils.h"
 #include "video_core/vulkan_common/vulkan_device.h"
 #include "video_core/vulkan_common/vulkan_wrapper.h"
 
@@ -148,7 +149,8 @@ VkRect2D GetScissorState(const Maxwell& regs, size_t index, u32 up_scale = 1, u3
     return scissor;
 }
 
-DrawParams MakeDrawParams(const MaxwellDrawState& draw_state, u32 num_instances, bool is_indexed) {
+DrawParams MakeDrawParams(const MaxwellDrawState& draw_state, u32 num_instances, bool is_indexed,
+                          Maxwell::PolygonMode polygon_mode) {
     DrawParams params{
         .base_instance = draw_state.base_instance,
         .num_instances = num_instances,
@@ -168,6 +170,21 @@ DrawParams MakeDrawParams(const MaxwellDrawState& draw_state, u32 num_instances,
         params.base_vertex = 0;
         params.is_indexed = true;
     }
+    const bool polygon_line =
+        draw_state.topology == Maxwell::PrimitiveTopology::Polygon &&
+        polygon_mode == Maxwell::PolygonMode::Line;
+    if (polygon_line) {
+        if (params.is_indexed) {
+            if (draw_state.index_buffer.count > 1) {
+                params.num_vertices = draw_state.index_buffer.count + 1;
+            }
+        } else if (draw_state.vertex_buffer.count > 1) {
+            params.num_vertices = draw_state.vertex_buffer.count + 1;
+            params.is_indexed = true;
+            params.first_index = 0;
+            params.base_vertex = draw_state.vertex_buffer.first;
+        }
+    }
     return params;
 }
 } // Anonymous namespace
@@ -236,7 +253,8 @@ void RasterizerVulkan::Draw(bool is_indexed, u32 instance_count) {
     PrepareDraw(is_indexed, [this, is_indexed, instance_count] {
         const auto& draw_state = maxwell3d->draw_manager->GetDrawState();
         const u32 num_instances{instance_count};
-        const DrawParams draw_params{MakeDrawParams(draw_state, num_instances, is_indexed)};
+        const auto polygon_mode = VideoCore::EffectivePolygonMode(maxwell3d->regs);
+        const DrawParams draw_params{MakeDrawParams(draw_state, num_instances, is_indexed, polygon_mode)};
         scheduler.Record([draw_params](vk::CommandBuffer cmdbuf) {
             if (draw_params.is_indexed) {
                 cmdbuf.DrawIndexed(draw_params.num_vertices, draw_params.num_instances,