Stencil buffer

This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages) You can help expand this article with text translated from the corresponding article in Serbian. (April 2014) Click [show] for important translation instructions. View a machine-translated version of the Serbian article. Machine translation, like DeepL or Google Translate, is a useful starting point for translations, but translators must revise errors as necessary and confirm that the translation is accurate, rather than simply copy-pasting machine-translated text into the English Wikipedia. Do not translate text that appears unreliable or low-quality. If possible, verify the text with references provided in the foreign-language article. You must provide copyright attribution in the edit summary accompanying your translation by providing an interlanguage link to the source of your translation. A model attribution edit summary is Content in this edit is translated from the existing Serbian Wikipedia article at [[:sr:¿¿¿¿¿¿¿_¿¿¿¿¿]]; see its history for attribution. You may also add the template {{Translated|sr|¿¿¿¿¿¿¿_¿¿¿¿¿}} to the talk page. For more guidance, see Wikipedia:Translation. This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Stencil buffer" – news · newspapers · books · scholar · JSTOR (January 2021) (Learn how and when to remove this message) This article may require cleanup to meet Wikipedia's quality standards. The specific problem is: The article does not clearly explain the concept of a stencil buffer. Please help improve this article if you can. (September 2013) (Learn how and when to remove this message) This article's factual accuracy may be compromised due to out-of-date information. Please help update this article to reflect recent events or newly available information. (January 2016) (Learn how and when to remove this message)

A stencil buffer is an extra data buffer, in addition to the color buffer and Z-buffer, found on modern graphics hardware. The buffer is per pixel and works on integer values, usually with a depth of one byte per pixel. The Z-buffer and stencil buffer often share the same area in the RAM of the graphics hardware.

In the simplest case, the stencil buffer is used to limit the area of rendering (stenciling). More advanced usage of the stencil buffer makes use of the strong connection between the Z-buffer and the stencil buffer in the rendering pipeline. For example, stencil values can be automatically increased/decreased for every pixel that fails or passes the depth test.

The simple combination of depth test and stencil modifiers make a vast number of effects possible (such as stencil shadow volumes, Two-Sided Stencil,^[1] compositing, decaling, dissolves, fades, swipes, silhouettes, outline drawing, or highlighting of intersections between complex primitives) though they often require several rendering passes and, therefore, can put a heavy load on the graphics hardware.

The most typical application is still to add shadows to 3D applications. It is also used for planar reflections.

Other rendering techniques, such as portal rendering, use the stencil buffer in other ways; for example, it can be used to find the area of the screen obscured by a portal and re-render those pixels correctly.

The stencil buffer and its modifiers can be accessed in computer graphics by using APIs like OpenGL, Direct3D, Vulkan or Metal.