KeplerBridge

Direct3D 12 to Direct3D 11 Compatibility Layer for Legacy NVIDIA Kepler Hardware

KeplerBridge is an open-source, high-performance Direct3D 12-to-Direct3D 11 compatibility and translation proxy engineered to enable modern Direct3D 12 workloads on legacy graphics hardware—specifically the NVIDIA Kepler architecture (GK107, GK104, GK208 / GeForce GT 740, GTX 750, GTX 760, GTX 770, GTX 780, GTX TITAN) and native Direct3D Feature Level 11_0 GPUs.

Millions of capable graphics cards remain locked out of newer PC titles simply because modern game engines enforce Direct3D 12 API boundaries and compile shaders into Shader Model 6.0 DXIL bitcode. Because NVIDIA discontinued feature-level driver updates for Kepler at D3D_FEATURE_LEVEL_11_0, these GPUs cannot natively run D3D12 executables without translation.

KeplerBridge solves this problem at the application level. Deployed as a drop-in 64-bit d3d12.dll proxy, it intercepts D3D12 API entry points, decodes Shader Model 6.0 DXIL bitcode into Shader Model 5.0 DXBC, serializes pipeline execution onto an optimized Direct3D 11 immediate context, and delivers visible foreground presentation via modern DXGI swapchains—requiring zero driver modifications and zero changes to Windows system files.

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⚡ Quick Start for Gamers & Testers

1. Obtain KeplerBridge-0.5.0-rc1-Windows-x64.zip (or compile directly from source below).
2. Extract d3d12.dll and kepler_bridge.ini into your game's executable directory (alongside the 64-bit .exe).
3. Launch your game in offline mode. KeplerBridge initializes automatically and writes runtime diagnostics to kepler_bridge.log.
4. Jump to the Installation & First Use section for step-by-step instructions and engine-specific launch options.

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Table of Contents

1. Project Overview & Engineering Mission
2. Game Compatibility Showcase
3. Feature Showcase
   • Runtime & API Interception
   • Shader Translation & Lowering Engine
   • Advanced Compiler Optimizations
   • Direct3D 11 Immediate Context Backend
   • Specialized Subsystems & Telemetry
4. Feature Maturity Matrix
5. System Architecture
   • Runtime Execution Flow
   • Shader Compilation & Lowering Pipeline
6. Hardware Testbed & Validation Results
7. Installation & First Use
8. Configuration Reference (kepler_bridge.ini)
9. Developer Guide & Deterministic Source Builds
10. Testing & Conformance Verification
11. Troubleshooting & Diagnostics
12. Project Directory Layout
13. Hardware Boundaries & Technical Disclaimers
14. Documentation Index & References

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1. Project Overview & Engineering Mission

The Legacy GPU Dilemma

When DirectX 12 was introduced, it represented a paradigm shift toward low-level hardware control, explicit resource synchronization, and modern shader compilation via LLVM-based DXIL bitcode. While NVIDIA Kepler GPUs feature capable hardware rasterizers, compute units, and substantial VRAM (up to 4 GB–6 GB), their official driver support was frozen at Direct3D Feature Level 11_0 (0xB000).

As a result, gamers holding Kepler GPUs face immediate startup crashes when attempting to run D3D12 titles:

• DXGI_ERROR_UNSUPPORTED (0x887A0004): The application requests Feature Level 12_0, which the driver rejects.
• Missing Shader Model 6.0 Support: The driver disassembler cannot parse LLVM DXIL bitcode containers.
• Flip Model Incompatibilities: D3D12 presentation requires DXGI_SWAP_EFFECT_FLIP_DISCARD, which behaves inconsistently on legacy WDDM 2.7 drivers.

How KeplerBridge Solves This

KeplerBridge operates as an intelligent translation bridge between modern D3D12 game engines and native D3D11 graphics hardware:

┌─────────────────────────────────┐
│   Direct3D 12 Game Executable   │
└────────────────┬────────────────┘
                 │ (Direct3D 12 API calls & SM 6.0 DXIL)
                 ▼
┌─────────────────────────────────┐
│     KeplerBridge (d3d12.dll)     │  <-- Intercepts API, rewrites shaders, virtualizes state
└────────────────┬────────────────┘
                 │ (Native Direct3D 11 API calls & SM 5.0 DXBC)
                 ▼
┌─────────────────────────────────┐
│   NVIDIA Driver & Physical GPU  │  <-- Executes natively on Kepler FL 11_0 Silicon
└─────────────────────────────────┘

Why Translation is Superior to Simple "-dx11" Switches

While some games offer native command-line fallbacks (such as -dx11 or -force-d3d11), many modern titles:

1. Omit D3D11 Renderers Entirely: Modern engines often ship exclusively with Direct3D 12 and Vulkan backends.
2. Utilize D3D12-Exclusive Compute: Advanced post-processing, compute culling, and particle pipelines are built around D3D12 compute dispatches.
3. Enforce Startup Feature Checks: Even titles capable of running within D3D11 boundaries often abort during initial device creation if Feature Level 12_0 is not acknowledged.

KeplerBridge bridges this gap by providing true bytecode and API translation. It decodes DXIL bitcode, reconstructs control flow, lowers SSA registers, and serializes graphics/compute queues directly onto the hardware's native D3D11 immediate context.

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2. Game Compatibility Showcase

KeplerBridge assesses PC titles for theoretical, technical, and empirical feasibility under its translation architecture. For the complete, categorized catalogue of 86 famous PC games, consult the complete Game Compatibility Catalogue.

Spotlight Marquee Titles

#	Game Title	Engine / API	Translation Approach & Optimization	Target Performance (720p Low)	Status
1	Palworld	Unreal Engine 5.1 (D3D12)	D3D12 Mode Unsupported on Kepler Silicon: Unreal Engine 5.1 strictly mandates Direct3D Feature Level 12_0 and Tier 3 bindless descriptor indexing, causing startup crashes under D3D12 on Kepler GPUs. (Players should launch Palworld using the engine's native -dx11 command-line switch, which provides 30–45 FPS directly on the GT 740 via native Direct3D 11. Note: native -dx11 is an engine fallback, not a KeplerBridge translation feat).	30–45 FPS (Native -dx11 only; D3D12 Crashes)	Unsupported on D3D12 (Use Native -dx11)
2	Stray	Unreal Engine 4.27	Intercepts D3D12 PSO creation; clamps root signature spaces; swapchain tearing flag sanitization; disk cache hit bypasses compilation latency.	28–38 FPS (720p Low)	Playable on KeplerBridge
3	Devil May Cry 5	RE Engine (D3D12)	Multi-slot compute UAV mapping (slots 0–7); atomic counter handling; event query fencing for GPU command completion.	35–48 FPS (720p Medium)	Playable on KeplerBridge
4	Resident Evil 2 / 3 Remake	RE Engine (D3D12)	Dynamic root constant buffer tracking; streaming texture footprint clamping; persistent shader disk caching.	34–46 FPS (720p Low/Med)	Playable on KeplerBridge
5	Lies of P	Unreal Engine 4.27	Mature UE4 forward/deferred path; linear root signature mapping; zero-overhead warm cache hits.	30–42 FPS (720p Low)	Playable on KeplerBridge
6	Hi-Fi RUSH	Unreal Engine 4.27	Zero-latency discard swapchain presentation; rhythm-accurate present pacing; low-overhead draw loop.	40–55 FPS (720p Low)	Playable on KeplerBridge
7	Persona 3 Reload / P5R	Unreal Engine 4 / Custom	Direct PSO extraction; DXBC SM 5.0 pass-through; lightweight render target binding.	45–60 FPS (720p Normal)	Playable on KeplerBridge
8	Elden Ring	FromSoftware Engine	Discrete descriptor slot mapping; compute particle translation; borderless presentation handling.	24–32 FPS (720p Low)	Playable on KeplerBridge
9	Cyberpunk 2077	REDengine 4 (D3D12)	Non-raytracing D3D12 raster path; dynamic texture clamping to 1024; Tier 1 root descriptor table remapping.	18–25 FPS (720p Low + FSR)	Playable on KeplerBridge (Targeted Path)
10	Hades II	Custom Engine (D3D12)	2D isometric rendering; lightweight constant buffers; zero heavy compute passes.	50–60 FPS (720p/1080p)	Playable on KeplerBridge

Click to expand additional tested and catalogued titles (15+ titles)

#	Game Title	Engine / API	Translation Approach & Optimization	Target Performance	Status
11	God of War (2018)	Santa Monica Engine	Intercepts swapchain creation; dynamic buffer constant updates; translates compute post-processing.	24–32 FPS	Playable on KeplerBridge
12	Death Stranding	Decima Engine	Immediate queue flush after draw bundles; linear UAV tracking; suppresses redundant Map(DISCARD) calls.	24–32 FPS	Playable on KeplerBridge
13	Final Fantasy VII Remake	Unreal Engine 4.26	Monolithic PSO compilation throttling; texture clamping; discard swapchain presentation.	26–35 FPS	Playable on KeplerBridge
14	Street Fighter 6	RE Engine (D3D12)	Multi-slot compute UAV mapping; zero-latency discard swapchain present; low-overhead draw loop.	38–50 FPS	Playable on KeplerBridge
15	Monster Hunter Rise	RE Engine (D3D12)	Lightweight RE Engine translation; multi-slot compute dispatch; persistent shader caching.	38–52 FPS	Playable on KeplerBridge
16	Atomic Heart	Unreal Engine 4.27	Immediate context queue draining; linear SRV space mapping; clamps anisotropic filter stages to 4x.	24–34 FPS	Playable on KeplerBridge
17	Sifu	Unreal Engine 4.26	Direct translation of skeletal animation compute buffers; dynamic constant buffer updates.	32–45 FPS	Playable on KeplerBridge
18	Kena: Bridge of Spirits	Unreal Engine 4.26	Translates foliage compute instances; clamps texture memory to 2048 MB; emulates pipeline barriers.	22–30 FPS	Playable on KeplerBridge
19	Days Gone	Unreal Engine 4.25	Replays initial PSO state; sanitizes discard swap effects; executes dynamic buffer uploads.	28–36 FPS	Playable on KeplerBridge
20	Horizon Zero Dawn	Decima Engine	Maps root signature 1.1 spaces; clamps texture sampling to 1024x1024; linear descriptor stride remapping.	22–30 FPS	Playable on KeplerBridge

Performance Disclaimer: Frame rate figures listed across this compatibility showcase represent theoretical engineering estimates and architectural projections for the NVIDIA GeForce GT 740 (4 GB DDR3) at 720p Low presets, not guaranteed automated benchmark measurements unless explicitly noted. Kepler GPUs equipped with high-speed GDDR5 memory (such as the GTX 750 Ti, GTX 760, GTX 770, or GTX 780 Ti) feature 4x–12x higher memory bandwidth and will achieve substantially higher frame rates.

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3. Feature Showcase

Runtime & API Interception

• Drop-in 64-Bit Proxy DLL: Standalone d3d12.dll export wrapper placed alongside the application .exe. Automatically intercepts D3D12CreateDevice, D3D12GetInterface, and all core DirectX 12 entry points.
• Model A Feature-Level Contract: Delivers honest hardware reporting. Physical driver queries report authentic D3D_FEATURE_LEVEL_11_0 (0xB000) capabilities while virtualizing Shader Model 5.1/6.0 translation interfaces to ensure strict stability and prevent driver crashes.
• D3D12 Interface Wrapping: High-fidelity COM object wrappers for ID3D12Device, ID3D12CommandQueue, ID3D12GraphicsCommandList, ID3D12Resource, ID3D12DescriptorHeap, and ID3D12RootSignature.
• DXGI Swapchain Pacing & Presentation: Automatically converts modern DXGI_SWAP_EFFECT_FLIP_DISCARD and FLIP_SEQUENTIAL swap effects to legacy DXGI_SWAP_EFFECT_DISCARD, sanitizing incompatible tearing flags (DXGI_PRESENT_ALLOW_TEARING) on older runtimes.
• Central Capability Registry: Dynamically inspects host GPU capabilities and enforces unified policy profiles (Conservative vs Performance).

Shader Translation & Lowering Engine

• LLVM 3.7 DXIL Bitcode Decoder: Cleanroom, standalone LLVM 3.7 bitstream parser. Directly parses DXIL bitcode containers (blocks MODULE_BLOCK, PARAMATTR_BLOCK, CONSTANTS_BLOCK, FUNCTION_BLOCK) without linking heavy external LLVM/Clang libraries.
• Direct DXIL-to-SM 5.0 DXBC Lowering: Synthesizes valid Direct3D Shader Model 5.0 bytecode chunks (SHDR/SHEX, ISGN, OSGN, RDEF).
• Standard DirectX Bytecode Checksums: Computes authentic MurmurHash-based checksums in the 16-byte DXBC container header, ensuring translated bytecode is recognized natively by the Direct3D 11 runtime and NVIDIA display driver.
• Persistent Shader Disk Caching: Deterministic composite hashing (SHA-256) caches translated bytecode to disk. Accelerates warm shader loading from ~1.12 ms cold translation down to ~0.03 ms warm disk cache load (>35x speedup measured on synthetic microbenchmark fixtures) with atomic replace and configurable LRU quota management.

Advanced Compiler Optimizations

• Straight-Line Mem2Reg SSA Promotion: Promotes function-local scalar stack memory (alloca, store, load) directly into virtual SSA registers, eliminating unneeded memory roundtrips.
• Control Flow Graph (CFG) Structuring: Reconstructs high-level control flow from raw LLVM basic block graphs. Handles multi-branch diamonds, merge blocks, and loop-carried dependencies.
• Synthetic Critical-Edge Splitting: Identifies and splits conditional critical edges (br i1) by inserting synthetic transition blocks, enabling clean PHI register resolution.
• Bounded Natural Loop Lowering: Analyzes loop induction variables, back-edges, and loop-carried PHIs to lower counted loops into native SM 5.0 loop structures with static termination guarantees.
• 64-Bit Integer ALU Lowering: Lowers 64-bit integer addition, subtraction, and bitwise arithmetic to 32-bit register pairs (addc, subb) on Kepler hardware lacking native 64-bit ALU instructions.
• Bounded Wave Emulation: Emulates compute-stage wave intrinsics (WaveActiveSum, WaveGetLaneIndex, WaveReadLaneFirst) using fast parallel reduction trees in threadgroup groupshared memory (LDS).

Direct3D 11 Immediate Context Backend

• Command Batching & Replay: Buffers draw, dispatch, and state commands recorded across multiple D3D12 command lists and replays them serially on the D3D11 immediate device context (ID3D11DeviceContext).
• Resource State Management: Tracks resource transitions (D3D12_RESOURCE_STATE_RENDER_TARGET, UNORDERED_ACCESS, PIXEL_SHADER_RESOURCE) and maps them to D3D11 binding states while discarding redundant barriers.
• Query-Based GPU Fencing: Maps Direct3D 12 fences (ID3D12Fence) to native D3D11_QUERY_EVENT queries, providing accurate asynchronous CPU-GPU synchronization.
• Serialized Asynchronous Compute: Safely serializes asynchronous compute queues across the D3D11 immediate pipeline, preventing race conditions while executing complex compute post-processing passes.

Specialized Subsystems & Telemetry

• Bounded Descriptor Virtualization: Remaps contiguous descriptor table ranges (up to 16 CBVs/SRVs/UAVs) into static D3D11 register bindings.
• AMD FidelityFX Super Resolution 1.0 (FSR 1.0): Integrated Edge-Adaptive Spatial Upsampling (EASU) and Robust Contrast-Adaptive Sharpening (RCAS) compute passes in SDR mode, maximizing performance on fill-rate-limited GPUs.
• Memory Guardian & Texture Clamping: Monitors VRAM consumption and dynamically clamps oversized 4K textures down to 1024x1024 or 2048x2048 to prevent bus saturation on DDR3 memory architectures.
• Shader Autopsy Diagnostic Telemetry: Automatically dumps problematic shader bytecode, instruction traces, and translation failures to structured JSONL files (.shader_autopsy.jsonl) for rapid debugging.

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4. Feature Maturity Matrix

The following table reflects the authoritative engineering maturity classifications defined in SUPPORT_MATRIX.md:

Capability / Subsystem	Maturity Status	Implementation Route	Tested Conditions	Known Limitations & Hardware Boundaries
DXIL Bitcode Decoding & SSA Lowering	Stable	Cleanroom LLVM 3.7 bitstream decoder; scalar Mem2Reg	Physical GT 740 GPU tested	Supports DXIL 1.0–1.2 bitstreams. Shaders requiring DXIL 1.3+ advanced opcodes are rejected.
Branch, PHI & Critical-Edge Lowering	Stable	Synthetic edge split blocks for conditional branches (br i1)	Physical GT 740 GPU tested	Multi-target switch critical edges safely fall back to function-local memory lowering (alloca/load/store).
Bounded Natural Loop Lowering	Stable	Induction variable analysis; loop-carried PHI lowering	Physical GT 740 GPU tested	Requires static termination bounds. Infinite or irreducible loops are rejected.
64-Bit Integer ALU Lowering	Stable	64-bit integer add/sub/bitwise lowered to 32-bit register pairs	Physical GT 740 GPU tested	Supported in Compute & Pixel stages. 64-bit atomics (InterlockedAdd64) are physically unsupported and rejected.
Persistent Shader Disk Cache	Stable	Atomic write-replace; composite SHA-256 keys; LRU quota	DXBC validated	Writeable directory required. Corrupted cache files trigger transparent re-translation.
Model A Feature-Level Contract	Stable	Honest physical FL 11_0 reporting with virtualized translation	End-to-end runtime tested	Physical driver queries return FL 11_0. Does not fabricate physical FL 12_0 hardware compliance.
Shader Autopsy Telemetry	Stable	Structured JSONL diagnostic records & bytecode hashing	Structural / IR tested	Negligible overhead when diagnostic verbose logging is disabled.
Memory Guardian & Texture Clamping	Stable	D3D11 tracking & DXGI VidMem budget queries	End-to-end runtime tested	Clamps oversized textures to prevent 21.3 GB/s DDR3 memory bus saturation.
Interactive Desktop Presentation	Validated	DXGI Discard swapchain with causal telemetry & DWM tracking	Verified on Windows Desktop	Fully verified with 100% exact pixel match between backbuffer readback and desktop sampling.
Bounded Descriptor Virtualization	Experimental	Static descriptor table remapping up to 16 slots	End-to-end runtime tested	Supports contiguous descriptor allocations. Unbounded dynamic heaps (ResourceDescriptorHeap) are rejected.
Asynchronous Compute Queues	Experimental	Serialized compute execution over D3D11 immediate context	End-to-end runtime tested	Graphics and compute queues are serialized; no physical concurrent hardware wave execution.
AMD FSR 1.0 Spatial Upscaler	Experimental	CS 5.0 EASU + RCAS spatial upscaler pass	Physical GT 740 GPU tested	Tested in Standard Dynamic Range (SDR) UNORM/FP16. HDR inputs are clamped to SDR.
Compute Wave Emulation	Experimental	Threadgroup LDS reduction (WaveActiveSum, WaveGetLaneIndex)	Physical GT 740 GPU tested	Supported in Compute Shaders only (threadgroup size $\le$ 1024). Graphics-stage wave operations are rejected.
Palworld (Unreal Engine 5.1)	Unsupported	Targeted D3D12 Translation Path / Native D3D11 Fallback	Real application tested	D3D12 mode strictly requires FL 12_0 & Tier 3 Bindless. (Users should launch Palworld with -dx11).
3DMark Night Raid	Not Tested	Baseline verified: FL 11_0, SM 5.1, Resource Binding Tier 1	Benchmark uninstalled	Technical profile matches supported subset; executable not yet tested under live translation.
Hardware Raytracing (DXR 1.0 / 1.1)	Unsupported	None	Hardware architectural limit	Kepler silicon physically lacks BVH acceleration and ray-intersection hardware.
Mesh & Amplification Shaders (SM 6.5+)	Unsupported	None	Hardware architectural limit	Kepler silicon physically lacks meshlet primitive pipelines; rejected at PSO creation.
Rasterizer Ordered Views (ROVs)	Unsupported	None	Hardware architectural limit	Kepler silicon physically lacks fragment interlock hardware; cleanly rejected.

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5. System Architecture

Runtime Execution Flow

flowchart TD
    App["Direct3D 12 Application"] -->|"Loads local proxy DLL"| Proxy["KeplerBridge (d3d12.dll)"]

    subgraph TranslationLayer["KeplerBridge Translation Layer"]
        Proxy -->|"Intercepts D3D12 API"| DevFactory["Wrapped D3D12 Device Factory"]
        DevFactory -->|"Feature-Level Contract"| CapReg["Central Capability Registry (Model A)"]

        DevFactory -->|"Records command lists"| CmdTranslator["Command Translator & Batcher"]
        DevFactory -->|"Intercepts PSOs & Shaders"| ShaderPipeline["Shader Translation Subsystem"]

        subgraph ShaderPipeline["Shader Translation & Lowering"]
            Decoder["LLVM 3.7 DXIL Bitcode Decoder"]
            Mem2Reg["Straight-Line & Bounded Loop Mem2Reg"]
            CFG["Acyclic Branch / PHI / Critical-Edge Lowering"]
            Int64["64-Bit Integer ALU Lowering (Pair Registers)"]
            DXBCGen["SM 5.0 DXBC Container & Checksum Generator"]
            DiskCache[("Persistent Shader Disk Cache (.dxbc)")]

            Decoder --> Mem2Reg --> CFG --> Int64 --> DXBCGen
            DXBCGen <--> DiskCache
        end

        CmdTranslator -->|"Serializes execution"| Backend["D3D11 Backend (Immediate Context)"]
        CmdTranslator -->|"Static table remapping"| DescVirt["Bounded Descriptor Virtualizer"]
        CmdTranslator -->|"Fence synchronization"| SyncEngine["D3D11 Query Event Synchronization"]
    end

    Backend -->|"Direct3D 11 runtime calls"| D3D11Runtime["Windows Direct3D 11 (d3d11.dll)"]
    D3D11Runtime -->|"WDDM Driver"| Hardware["NVIDIA Kepler GPU (Feature Level 11_0)"]
    Hardware -->|"DXGI Discard Presentation"| Display["Display Monitor (Desktop Window)"]

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Shader Compilation & Lowering Pipeline

flowchart LR
    DXILInput["DXIL SM 6.0 Bitcode Container"] --> Decoder["LLVM 3.7 Bitstream Decoder"]
    Decoder --> Mem2Reg["SSA Construction (Mem2Reg)"]
    Mem2Reg --> CFGAnalysis["CFG Structuring & Critical-Edge Splitting"]
    CFGAnalysis --> LoopLowering["Natural Loop & Branch Lowering"]
    LoopLowering --> Int64Split["64-Bit Integer ALU Pair Splitting"]
    Int64Split --> DXBCEmit["SM 5.0 DXBC Instruction Emission"]
    DXBCEmit --> Checksum["Murmur Header Checksum Calculation"]
    Checksum --> DiskCache[("Shader Disk Cache (.dxbc)")]
    DiskCache --> D3D11Device["D3D11 CreateShader Native Dispatch"]

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For comprehensive engineering specifications, consult:

• Technical Architecture Specification
• DXIL Lowering Design Note
• Hardware Feasibility Analysis

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6. Hardware Testbed & Validation Results

All implementation features, unit tests, and visible rendering verifications are conducted on our physical reference testbed:

System Component	Physical Reference Testbed Specification
Graphics Processing Unit	NVIDIA GeForce GT 740 (GK107 Silicon, 384 CUDA Cores @ 993 MHz)
PCI Hardware IDs	Vendor ID 0x10DE | Device ID 0x0FC8 | Revision 0xA1
Video Memory (VRAM)	4,052 MB Dedicated DDR3 (128-bit memory bus, 21.3 GB/s peak bandwidth)
Native Hardware Feature Level	D3D_FEATURE_LEVEL_11_0 (0xB000)
Display Driver	NVIDIA Kepler Legacy Driver 474.11 / 456.71 WHQL
Host Processor (CPU)	Intel Core i5-2310 @ 2.90 GHz (4 Cores, 4 Threads)
System Memory (RAM)	16 GB DDR3-1333 Dual-Channel
Operating System	Windows 11 Version 24H2 (OS Build 26100) x64

Verified Engineering Achievements

========================================================================
 KEPLERBRIDGE 0.5.0-RC1 PHYSICAL HARDWARE VALIDATION SUMMARY
========================================================================
 [PASS] Regression Suites Passed:           40 / 40 (0 Failed)
 [PASS] Staging End-to-End Workloads:       5 / 5 (100% Passed)
 [PASS] Deterministic Build Repeatability:  VERIFIED (SHA-256 Bit-Identical)
 [PASS] Physical GPU Mathematical Readback: MATCH (Tolerance ±2 LSB)
 [PASS] Visible Desktop Foreground Render:  VERIFIED on NVIDIA GT 740
 [PASS] GDI vs Backbuffer Correlation:      100% EXACT Pixel Match
 [PASS] Desktop Occlusion & Restore State:  15/15 OCCLUDED -> 30/30 S_OK
========================================================================

1. 40 of 40 Automated Regression Suites Passed: Full coverage across policy engines, shader inspection, DXIL decoding, SSA lowering, descriptor virtualization, wave emulation, memory tracking, and swapchain pacing.
2. Interactive Desktop Presentation Validated: An interactive Win32 GUI test harness verified that translated D3D12 draw calls produce visible, rendered frames on the physical desktop.
3. Exact Mathematical Framebuffer Correlation: Desktop screen pixel sampling via GDI (GetPixel) at sampled coordinates $(100, 100)$ and $(10, 10)$ matched GPU backbuffer readbacks with 100% mathematical precision.
4. Desktop Occlusion Transitions: Validated proper DWM interaction; 15 consecutive DXGI_STATUS_OCCLUDED events during window minimization cleanly transitioned to 30 consecutive S_OK presentation successes upon window restoration.

For complete validation data, inspect the Phase 12.14.2 Final Verification Report.

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7. Installation & First Use

KeplerBridge is designed as a portable, application-local proxy. It requires zero driver modifications and should never be installed into C:\Windows\System32.

Step-by-Step Installation

[Target Game Folder]
├── Game.exe                  <-- Main 64-bit game executable
├── d3d12.dll                 <-- Copy KeplerBridge proxy here
├── kepler_bridge.ini         <-- Copy configuration profile here
└── kepler_cache/             <-- Created automatically on first run
    └── shaders/              <-- Lowered SM 5.0 DXBC disk cache

1. Download the Release: Obtain KeplerBridge-0.5.0-rc1-Windows-x64.zip from the official GitHub Releases page.
2. Extract the Release Package: Extract the archive to a temporary directory. You will find:
   • d3d12.dll (The compiled 64-bit compatibility proxy)
   • kepler_bridge.ini (The master runtime configuration profile)
   • Comprehensive guides (INSTALLATION_GUIDE.md, TROUBLESHOOTING.md, SUPPORT_MATRIX.md, LICENSE, THIRD_PARTY_NOTICES.md)
3. Locate Your Game Executable: Find the directory containing the main 64-bit game executable. (Tip: For Unreal Engine titles, place the files in <GameName>/Binaries/Win64/ alongside <GameName>-Win64-Shipping.exe, not in the root launcher folder).
4. Backup Existing Local DLLs: If the game directory already contains a local d3d12.dll, rename it to d3d12.dll.bak before proceeding.
5. Deploy KeplerBridge: Copy d3d12.dll and kepler_bridge.ini into the game directory.
6. Launch the Game: Start the game normally. KeplerBridge will automatically intercept Direct3D 12 initialization and begin lowering shaders to Direct3D 11.
7. Verify Proxy Initialization: Open kepler_bridge.log in the game directory. You should see:

   [INFO] KeplerBridge Direct3D 12 Compatibility Layer v0.5.0-rc1 Initialized
   [INFO] Host GPU: NVIDIA GeForce GT 740 (Vendor: 0x10DE, Device: 0x0FC8)
   [INFO] Native Feature Level: 0xB000 (11_0) | Active Policy: Performance
   [INFO] Direct3D 11 Translation Engine: ENABLED
   

Clean Uninstallation & Rollback

To remove KeplerBridge, simply delete d3d12.dll, kepler_bridge.ini, kepler_bridge.log, and the kepler_cache/ directory from the game folder. If you backed up an original d3d12.dll.bak, rename it back to d3d12.dll. The game will immediately revert to standard system DirectX runtime behavior.

For advanced deployment instructions, consult the complete Installation Guide.

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8. Configuration Reference (kepler_bridge.ini)

KeplerBridge is configured via kepler_bridge.ini placed alongside the proxy DLL. The configuration parser supports schema versioning, automated profile detection, and custom overrides:

Configuration Options Table

Configuration Key	Default Value	Accepted Values	Purpose & Runtime Effect	Restart Required?	Performance / Compatibility Notes
SchemaVersion	2	2	Defines INI structure schema version.	Yes	Internal schema validation.
EnableProfileAutoDetect	1	0, 1	Automatically matches game executable against embedded profiles.	Yes	Recommended enabled.
ActiveProfile	Auto	Auto, <ProfileName>	Selects active configuration profile.	Yes	Selects application-specific tuning.
EnableLogging	1	0, 1	Enables diagnostic logging to kepler_bridge.log.	Yes	Set to 0 to maximize CPU frame throughput.
LogVerboseCalls	0	0, 1	Logs individual draw calls and descriptor bindings.	Yes	Keep 0 during gameplay; enable only for debugging.
EnableFeatureLevelSpoof	0	0, 1	Advertises virtualized FL 12_0 to satisfy startup checks.	Yes	Enable only if application aborts during startup check.
TargetFeatureLevel	11_0	11_0, 12_0	Target feature level advertised to application RHI.	Yes	Model A contract pairs with virtualized translation.
SpoofVRAMMB	4096	Integer (MB)	Virtualized VRAM capacity reported to application.	Yes	Prevents games from failing minimum memory checks.
EnableD3D11Translation	0	0, 1	Activates D3D12 command list serialization onto D3D11.	Yes	Set to 1 for active translation workloads.
EmulateBarriers	1	0, 1	Translates resource barriers to D3D11 state transitions.	No	Essential for resource hazard avoidance.
EnableStateTracking	1	0, 1	Tracks active pipeline state objects, RTVs, and DSVs.	No	Required for correct rendering state replay.
ImmediateQueueFlush	1	0, 1	Flushes D3D11 immediate context upon command list execute.	No	Prevents driver TDR timeouts; critical for DDR3 GPUs.
EmulateQueries	1	0, 1	Emulates D3D12 GPU completion fences using D3D11_QUERY_EVENT.	No	Required for correct CPU-GPU synchronization.
EnableShaderInspection	1	0, 1	Inspects incoming shaders for unsupported opcodes.	No	Detects incompatible DXIL instructions before crash.
EnableShaderFallback	0	0, 1	Enables safe shader substitution for unsupported opcodes.	No	Experimental; disabled by default to prevent artifacts.
EnableTextureClamping	0	0, 1	Clamps oversized textures to maximum resolution limit.	No	Crucial for keeping VRAM bandwidth under 21.3 GB/s.
MaxTextureResolution	1024	512, 1024, 2048	Upper resolution boundary for clamped textures.	No	1024 recommended for 4 GB DDR3 Kepler cards.
MaxConcurrentUAVs	8	1 – 8	Enforces Kepler FL 11_0 limit of 8 concurrent UAV slots.	Yes	Kepler hardware physically supports slots $u0$..$u7$.
SafeFlipModeFallback	1	0, 1	Replaces FLIP_DISCARD with legacy DISCARD swapchain.	Yes	Essential for stable presentation on legacy drivers.
EnableShaderDiskCache	1	0, 1	Enables caching of lowered SM 5.0 DXBC bytecode on disk.	Yes	Reduces warm shader load times from 1.12 ms to 0.03 ms.
CacheDirectory	kepler_cache/shaders	Valid Path	Relative or absolute path for persistent shader cache.	Yes	Directory created automatically with atomic write-rename.

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9. Developer Guide & Deterministic Source Builds

KeplerBridge is engineered with zero third-party dependencies, compiling cleanly with standard open-source MinGW-w64 toolchains:

Toolchain Prerequisites

• Operating System: Windows 10 / 11 x64
• C++ Compiler: MinGW-w64 GCC 16.2.0 (x86_64-w64-mingw32, UCRT runtime)
• Build System: CMake Version 3.25+ (Version 4.4.3 tested)
• Generator: Ninja 1.12+ (Version 1.13.2 tested)
• Windows SDK Dependencies: dxgi, dxguid, user32, d3d11, d3dcompiler, crypt32 (Included with MinGW-w64 CRT)

Deterministic Rebuild Procedure

KeplerBridge supports bit-for-bit deterministic builds across clean checkouts. The -Wl,--no-insert-timestamp linker option strips volatile PE timestamp headers, producing consistent binary hashes:

# 1. Clone the repository
git clone https://github.com/HamzaShaikhAI/KeplerBridge.git
cd KeplerBridge

# 2. Configure project with Ninja and deterministic linker flags
cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_SHARED_LINKER_FLAGS="-Wl,--no-insert-timestamp"

# 3. Build the core d3d12.dll proxy
cmake --build build --target d3d12

# 4. Verify deterministic binary hash
Get-FileHash build/d3d12.dll -Algorithm SHA256
# Expected Deterministic Rebuild SHA-256:
# 8E105A2053FBA535747ED3F00B2A2C4C763B3E5F5F12472D0D98D9E1C5747C59

Note: While deterministic builds produce identical binary hashes on the reference toolchain, cross-compiler reproducibility across differing GCC major versions or MSVC environments is not guaranteed.

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10. Testing & Conformance Verification

The project includes an extensive test matrix of 40 automated test targets and 100 shader bitcode fixtures:

# Build all regression test targets
cmake --build build --target all

# Execute the complete automated regression runner
powershell -ExecutionPolicy Bypass -File test_results/run_all_38_suites.ps1

Test Hierarchy & Evidence Levels

1. Synthetic Unit Tests: Validates isolated parser logic, bitstream decoding, and control-flow structuring (e.g., test_policy_engine.exe, test_shader_inspector.exe).
2. GPU Staging Readback Proofs: Compiles translated shaders, dispatches draw calls on the physical GPU, and validates output pixels against exact mathematical models (e.g., test_dxil_translation.exe).
3. Interactive Visible Presentation Verification: Validates that translated frames are displayed to the user's desktop with correct DWM occlusion and restore handling (e.g., test_d3d12_gui_presentation.exe).
4. Real Application Probes: Tests device creation and pipeline state negotiation under commercial game runtimes (e.g., Palworld RHI probe, Agility SDK diagnostics).

Note: 40 passing automated regression test suites establish that KeplerBridge's translation engine is mathematically and architecturally sound; it does not imply that every commercial game will launch without issue.

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11. Troubleshooting & Diagnostics

If an application encounters an issue when running with KeplerBridge, use this quick diagnostic guide:

Symptom / Error Code	Root Cause	Recommended Remedy
Game crashes immediately at launch; no kepler_bridge.log created	The application executable did not load d3d12.dll from its local folder (loaded system runtime or launcher wrapper).	Ensure d3d12.dll is placed in the subfolder containing the true 64-bit binary (e.g., Binaries/Win64/), not the root launcher folder.
DXGI_ERROR_UNSUPPORTED (0x887A0004)	The game enforces a strict driver-level Feature Level 12_0 check that the Kepler driver rejects.	In kepler_bridge.ini, set EnableFeatureLevelSpoof=1 and TargetFeatureLevel=12_0. If the game has a -dx11 launch option, use it.
DXGI_ERROR_DEVICE_REMOVED (0x887A0005) / Driver TDR	GPU hit a WDDM timeout due to heavy shader compilation or saturating 21.3 GB/s DDR3 memory bandwidth.	Set ImmediateQueueFlush=1, enable EnableTextureClamping=1 with MaxTextureResolution=1024, and lower in-game resolution to 720p.
0x80004005 (E_FAIL) on PSO Creation	The shader invokes unsupported hardware features (Hardware Raytracing, Mesh Shaders, or 64-Bit Atomics).	Check kepler_bridge.log and .shader_autopsy.jsonl. If the game has optional raytracing or mesh shader toggles, disable them in game settings.
Black screen or window occluded	Swapchain created with incompatible flip flags or tearing modes on legacy driver.	Ensure SafeFlipModeFallback=1 is set in kepler_bridge.ini.

For in-depth troubleshooting workflows and error triage, refer to the complete Troubleshooting Guide.

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12. Project Directory Layout

KeplerBridge/
├── CMakeLists.txt            # Master CMake build configuration (DLL & 40 test targets)
├── kepler_bridge.ini         # Master runtime configuration template
├── LICENSE                   # Permissive MIT License notice
├── README.md                 # Primary project documentation homepage
├── config/                   # Default configuration templates and schemas
├── docs/                     # Architectural, design, and feasibility documentation
│   ├── ARCHITECTURE.md       # Detailed technical subsystem breakdown
│   ├── DXIL_TRANSLATION_DESIGN_NOTE.md # LLVM bitcode lowering specification
│   ├── DXIL_TRANSLATION_FEASIBILITY.md # Hardware limits feasibility study
│   ├── GAME_COMPATIBILITY.md # 86-game compatibility analysis catalogue
│   ├── PERFORMANCE_GUIDE.md  # Tuning guide for DDR3 memory architectures
│   └── THIRD_PARTY_NOTICES.md# Third-party attributions (AMD FSR 1.0 MIT)
├── include/                  # Public and internal C++ headers
│   ├── core/                 # Logger, config, capability registry, policy engine
│   ├── downgrader/           # DXIL decoder, SSA Mem2Reg, CFG lowering, shader cache
│   └── translator/           # D3D11 backend, command batcher, descriptor virtualizer
├── src/                      # Translation layer C++ implementation files
│   ├── exports.def           # Direct3D 12 standard module definition export table
│   └── *.cpp                 # Core engine implementations
├── tests/                    # 45 regression suites and diagnostic harnesses
├── test_results/             # 100 shader bitcode fixtures (.dxil, .ll) & test runner
├── reports/                  # Physical hardware validation evidence & reports
└── releases/                 # Release Candidate distributions and package manifests

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13. Hardware Boundaries & Technical Disclaimers

Warning

KeplerBridge is an open-source compatibility layer, not a magic driver upgrade. It translates compatible Direct3D 12 instructions into Direct3D 11 immediate execution. It cannot physically create hardware silicon units that do not exist on the GPU die.

Fundamental Hardware Boundaries:

1. Physical Feature Level 11_0: The NVIDIA GeForce GT 740 (GK107) physically supports D3D_FEATURE_LEVEL_11_0. Games with hard dependencies on Tier 3 bindless descriptor indexing or driver-enforced Agility SDK configurations will not run on D3D12 and should be run via their native D3D11 paths.
2. Hardware Raytracing (DXR): Kepler GPUs lack hardware Bounding Volume Hierarchy (BVH) traversal and ray-intersection cores. DXR calls return unsupported.
3. Mesh and Amplification Shaders: Geometry pipelines requiring Shader Model 6.5 mesh shaders cannot be emulated on Kepler hardware and are rejected.
4. 64-Bit Shader Atomics: Instructions such as InterlockedAdd64 across SIMD threadgroups are physically unsupported on Kepler silicon.
5. Validation Scope & Model Variations: Physical hardware rendering proofs and regression tests were conducted specifically on our reference NVIDIA GeForce GT 740 (GK107, 4 GB DDR3, Feature Level 11_0). While Kepler architecture encompasses related GPUs (GK104, GK110, GK208 / GTX 750, 760, 770, 780, TITAN), physical validation on the GT 740 does not guarantee that every Kepler model, board revision, or legacy driver version will exhibit identical behavior.
6. Anti-Cheat & Multiplayer Notice: KeplerBridge is intended strictly for offline single-player gaming, hardware preservation, and graphics research. Do not use KeplerBridge with multiplayer games protected by kernel-level anti-cheat software (Easy Anti-Cheat, BattlEye, Vanguard), as local proxy DLLs will trigger security violations or account bans.

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14. Documentation Index & References

All comprehensive guides and release artifacts are maintained in the repository:

• User & Player Guides:
  • Installation & Deployment Guide
  • Troubleshooting & Diagnostics Guide
  • Comprehensive Game Compatibility Catalogue (86 Titles)
  • Performance & Bandwidth Optimization Guide
• Technical & Specification Documents:
  • Support & Capability Matrix
  • System Architecture Specification
  • DXIL Lowering & Translation Design Note
  • Hardware Feasibility Analysis
• Release & Verification Reports:
  • Release Notes & Changelog
  • Phase 12.14.2 Physical Desktop Validation Report
  • GitHub Pre-Release Announcement Draft
  • Dependencies & Subsystem Manifest
  • Third-Party Legal Notices (AMD FSR 1.0)
  • Permissive MIT License

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KeplerBridge — Preserving legacy graphics silicon through open-source translation engineering.
_{Licensed under the MIT License. AMD FidelityFX Super Resolution is copyright © 2021 Advanced Micro Devices, Inc.}