forge-edge-detection

Add Sobel edge detection, stencil X-ray vision, and Fresnel ghost silhouettes to SDL GPU projects.

36|6|Updated Mar 25, 2026
One-click install
npx skills add https://github.com/Nebulavenus/forge-gpu --skill forge-edge-detection-nebulavenus
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: forge-edge-detection
Source: https://github.com/Nebulavenus/forge-gpu/tree/main/.claude/skills/forge-edge-detection
Command: npx skills add https://github.com/Nebulavenus/forge-gpu --skill forge-edge-detection-nebulavenus

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Enhances real-time render feedback by enabling clear object outlines and occlusion hints through Sobel-based edge detection on G-buffer data, plus optional X-ray visibility and ghost silhouettes.

Core Features & Use Cases

  • Sobel edge detection on depth and view-space normals rendered to an MRT G-buffer (depth + normals) to reveal geometry boundaries.
  • Stencil-based X-ray vision using depth_fail_op to mark occluded objects for selective visibility.
  • Fresnel ghost silhouettes rendered additively to emphasize silhouette edges and hidden geometry.

Quick Start

Integrate the edge-detection and ghost passes into your SDL GPU pipeline by enabling MRT-based depth/normal rendering and applying Sobel, stencil, and additive blending effects.

Frequently Asked Questions about forge-edge-detection

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I add edge detection and X-ray vision to an SDL GPU rendering pipeline?▼

You can add edge detection and X-ray vision to SDL GPU pipelines by using a G-buffer MRT for depth and normals, applying Sobel filtering for edges, and using depth_fail_op stencil updates to reveal occluded geometry.

What does Sobel edge detection on a G-buffer do for real-time rendering?▼

Sobel edge detection on a G-buffer processes depth and view-space normals to reveal geometry boundaries in real-time rendering. This highlights object outlines and provides clear visual feedback for structural edges.

Can I render Fresnel ghost silhouettes using depth and normals in SDL?▼

Yes, you can render Fresnel ghost silhouettes in SDL by applying additive blending to silhouette edges. This emphasizes hidden geometry by additively combining ghost outlines with your existing scene rendering.

Do I need multiple render targets to use stencil-based X-ray occlusion effects?▼

Yes, you need two MRT targets for color and normals plus a depth-stencil buffer. The stencil-based X-ray vision uses depth_fail_op operations on this buffer to mark and selectively reveal occluded objects.

How does depth_fail_op stencil updates work for revealing occluded objects?▼

Depth_fail_op stencil updates mark occluded objects by modifying stencil values where depth tests fail. This allows selective visibility rendering, making hidden geometry visible as an X-ray silhouette effect.

What is the best way to reveal hidden geometry boundaries in a real-time SDL application?▼

The best way to reveal hidden geometry in SDL is combining Sobel edge detection on view-space normals with stencil-based X-ray vision. This approach highlights both visible boundaries and occluded structural edges.