DirectX Visualizer (DDV) Guide

Introduction to the DirectX Visualizer (DDV)

The DirectX Visualizer (DDV) is a powerful debugging and analysis tool for developers working with DirectX graphics on Windows. It allows you to inspect, capture, and analyze graphics API calls, resource states, and performance metrics in real-time.

DDV is essential for identifying rendering issues, understanding pipeline bottlenecks, and optimizing your DirectX applications. This guide provides an overview of DDV's capabilities and how to effectively use it.

Key Features

  • Real-time API Call Monitoring: Capture and inspect every DirectX function call made by your application.
  • Resource Inspection: View the contents of textures, buffers, render targets, and other GPU resources at any point during execution.
  • Performance Profiling: Analyze frame times, draw call statistics, and shader execution times to identify performance issues.
  • Shader Debugging: Step through shader code, inspect variables, and understand shader execution flow.
  • State Tracking: Monitor the graphics pipeline state, including render states, shader stages, and bound resources.
  • Capture and Replay: Record entire frames or sequences of API calls for later analysis, even after the application has terminated.
DirectX Visualizer Main Interface
The main interface of the DirectX Visualizer.

Getting Started with DDV

Installation and Setup

DDV is typically included as part of the Windows SDK or development tools. Ensure you have the latest Windows SDK installed for the most up-to-date version of DDV.

  1. Locate the DDV executable (often named d3d11_1.dll or similar, depending on the version and target API) within your SDK installation directory.
  2. Launch DDV.
  3. In your DirectX application, configure it to use DDV. This often involves setting environment variables or using specific initialization flags. Refer to the specific DirectX version documentation for details.

Launching and Attaching to an Application

You can launch DDV and attach it to a running DirectX application, or launch your application directly through DDV.

  • Attaching: Run your DirectX application first. Then, open DDV and select "Attach to Process" from the File menu, choosing your application's process.
  • Launching: Open DDV, go to File > Launch Application, and select your application's executable. DDV will then launch your application under its control.

Core DDV Functionality

API Call Trace

The API Call Trace view is your primary window for understanding the sequence of DirectX commands. You can see:

  • The function name and its arguments.
  • The return value of the function.
  • Which thread made the call.
  • Timestamps for each call.

You can filter calls by type, thread, or specific API functions to narrow down your search.


// Example API Call in Trace
D3D11_CALL(ID3D11DeviceContext_DrawIndexed(pContext, 12, 0, 0));
// Arguments: IndexCount=12, StartIndexLocation=0, BaseVertexLocation=0
// Thread: MainThread (ID: 4568)
// Time: 123.456 ms

Resource Viewer

The Resource Viewer allows you to inspect the data held within DirectX resources.

  • Textures: View texture data, mipmaps, and different array slices. You can export textures as image files.
  • Buffers: Examine the raw data in vertex buffers, index buffers, constant buffers, and structured buffers.
  • Render Targets & Depth-Stencil Buffers: See the current contents of what's being rendered to the screen.

Right-click on a resource in the object inspector to open it in the Resource Viewer.

DirectX Visualizer Resource Viewer
Inspecting a texture resource in DDV.

Performance Analysis

DDV provides insights into your application's performance:

  • Frame Times: Monitor the duration of each frame to identify stuttering or frame rate drops.
  • Draw Call Profiling: Analyze the number of draw calls and their associated costs. Excessive draw calls can be a performance bottleneck.
  • Shader Statistics: Understand how much time is spent in different shader stages (vertex, pixel, geometry, etc.).

The Performance tab offers various graphs and tables to visualize these metrics.

Performance Tip: Batching draw calls by using techniques like instancing or combining meshes can significantly improve performance by reducing CPU overhead.

Advanced DDV Techniques

Shader Debugging

For shader debugging, DDV integrates with dedicated shader debuggers. You can set breakpoints within your shader code, inspect variables, and step through execution line by line to find bugs.

To enable shader debugging, ensure your shaders are compiled with debugging symbols (e.g., using the /Zi flag for HLSL compilation).

Capture and Replay

The capture and replay feature is invaluable for debugging issues that are difficult to reproduce or occur sporadically.

  • Capture: Start a capture session in DDV. All subsequent API calls and resource states will be recorded.
  • Stop Capture: End the capture when you have observed the problematic behavior.
  • Save Capture: Save the recorded data to a file (often with a .gcd extension).
  • Replay: Open the saved capture file in DDV. You can then step through the captured sequence of events as if your application were running, inspect states, and analyze the issue at your own pace.

This is especially useful for diagnosing crashes or rendering artifacts that happen at specific moments.

Related Resources