Watki vs Surface Explorer
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Watki
This app provides offline access to detailed descriptions of all OpenGL ES commands and functions from the official Khronos Group website. It's designed to help developers easily reference graphics API information, even for beginners.
- Complete OpenGL ES 3.2 command descriptions
- Information from official Khronos Group website
- Offline access
- Systematic function listing
- Search bar and index
- Landscape mode support
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Watki is an offline field guide to open graphics, compute and XR standards. Every call, built-in and type, with what it does, what it takes and where it fits, set in a quiet black-and-white reader that works without a connection. WHAT'S INSIDE 21 volumes and more than 12,000 entries, including: • Vulkan 1.4 and Vulkan SC 1.0, with extensions • OpenGL ES 2.0 to 3.2, OpenGL 4.6 core and OpenGL SC 2.0 • EGL 1.5 and WebGL 1.0 and 2.0, with extensions • OpenCL 3.0 and OpenCL C, SYCL 2020 and SPIR-V 1.6 • OpenXR 1.1, OpenVX 1.3.1, OpenVG 1.1 and ANARI 1.1 • The Slang core module • glTF 2.0, KTX 2.0, COLLADA 1.5 and NNEF 1.0.5 • Short overviews of machine learning and safety-critical work HOW IT READS • Each volume opens to its sections; each section lists its entries in groups you can jump between. • Entries show the signature, parameters, return values and the version or extension that added them. • Search across every volume at once. • Keep the entries you use most and come back to recent ones. • See how much of each volume you have read. MADE TO BE LOOKED AT A slow mist drifts behind the pages and changes with the time of day. You can thicken it, slow it, freeze it or give it a new pattern. In the darkroom you can develop any photo as a 1-bit print and save it. PRIVATE AND OFFLINE Everything ships inside the app. No account, no ads, no tracking and no data collected. SOURCES The reference text is generated from the published registries, headers and reference pages of each standard, under their licences. Full credits and licence details are in the app. Watki is an independent reader and is not affiliated with or endorsed by The Khronos Group or any other standards body. Vulkan, OpenGL ES, OpenGL SC, EGL, WebGL, OpenCL, SYCL, SPIR-V, OpenXR, OpenVX, OpenVG, ANARI, glTF, KTX, COLLADA, NNEF and Khronos are trademarks or registered trademarks of The Khronos Group Inc. OpenGL is a registered trademark of Hewlett Packard Enterprise, used under licence by Khronos. Slang is a trademark of its respective owner. All other names are the property of their owners and are used only to identify the standards described.
Surface Explorer
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Surface Explorer is a high-performance visualizer for intricate mathematical surfaces — 2D manifolds embedded in three- or four-dimensional space, and 3D slices of four-dimensional hypersurfaces — bringing abstract geometry to life with real-time GPU rendering. KEY FEATURES • Cross Section — slice four-dimensional hypersurfaces and watch their 3D sections change shape as you rotate them in 4D or slide the cutting plane along the fourth axis, even along a 4D camera path. • Ray Marching Engine — real-time rendering of implicit surfaces and signed-distance fields, with procedural displacement, transparency, adjustable shells, and a precise mode for high-degree equations. • Multi-Mesh Surfaces — build figures from several independent grids, set with a single field or a script, each with its own color, transparency, texture, image and domain. • Solid Curve — write a curve in 3D or 4D and see the tube drawn around it, with adjustable thickness; several tubes from a script. • Surface Borders — add a tube along the edges of a parametric surface, with its own color, texture and thickness. • Geodesic Flow — explore intrinsic geometry on curved manifolds (S³, H²×R, SL(2,R) and more), integrating geodesics from initial conditions. • 4D Spatial Exploration — dedicated controls for hyperspatial rotation (Omega, Phi, Psi), projection, and 3D and 4D camera paths. • 4D Lighting Models — Directional, Observer, and Slice lighting designed for hyperspace. • Dynamic GLSL Scripting — write custom shaders for procedural textures and surface logic in the built-in editor. • Backgrounds — images and procedural effects, fixed on screen or wrapped around the scene as a sphere, cylinder or cube. • Audio-Visual Synthesis — synchronize geometric parameters with a mathematical sound synthesizer. • Video Recording — capture your explorations directly in the app and save them to your device. A library of ready-made presets ships with the app, from classic parametric surfaces to black-hole ergospheres, curved-space tori and slices of the 3-torus, together with a searchable built-in manual. Built with Qt and Metal for smooth, native performance on iPhone and iPad.
Screenshots
Verdict
The clearest difference is update cadence: Surface Explorer at every 2 weeks against Watki's every 134 months. On price, ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
Watki ships an update every 134 months, Surface Explorer every 2 weeks. The most recent releases landed on November 11, 2026 and November 5, 2026 respectively.
| Parameter | Watki | Surface Explorer |
|---|---|---|
| Price | Free | Free |
| Rating | 3.0 (3 ratings) — better | — |
| Positive reviews | 66.7% of reviews | — |
| Number of ratings | 3 — better | — |
| Update frequency | Every 134 months | Every 2 weeks — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone, iPad | iPhone, iPad, Mac — better |
| Requires iOS | 18.0 | 17.0 — better |
| Further details — not scored | ||
| Size | 7 MB | 62 MB |
| Age rating | 4+ | 4+ |
| Developer | Saumya Lahera | GAETANO MOSCHETTI |
In-app purchases
Watki
No in-app purchases
Surface Explorer
No in-app purchases
Questions
Is Watki free?
Is Surface Explorer free?
Do Watki or Surface Explorer have ads?
Which is updated more often, Watki or Surface Explorer?
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