Stencil buffer
The Z-buffer and stencil buffer often share the same area in the RAM of the graphics hardware.
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 stencil buffer and its modifiers can be accessed in computer graphics by using APIs like OpenGL, Direct3D, Vulkan or Metal.
The first chip available to a wider market was 3Dlabs' Permedia II, which supported a one-bit stencil buffer.
In doing so, the possible reaction caused by the result of comparing three different state-depth and stencil buffer: For each of these cases can be set different operations over the examined pixel.
Due to the lack of precision in the Z-buffer, coplanar polygons that are short-range, or overlapping, can be portrayed as a single plane with a multitude of irregular cross-sections.
- Increase the number of bits allocated to the Z-buffer, which is possible at the expense of memory for the stencil buffer.
- Move polygons farther apart from one another, which restricts the possibilities for the artist to create an elaborate scene.
All of these approaches to the problem can only reduce the likelihood that the polygons will experience Z-fighting, and do not guarantee a definitive solution in the general case.
They were first proposed by Frank Crow in 1977[2] as the geometry describing the 3D shape of the region occluded from a light source.
Reflection of a scene is drawn as the scene itself transformed and reflected relative to the "mirror" plane, which requires multiple render passes and using of stencil buffer to restrict areas where the current render pass works: While drawing a plane of shadows, there are two dominant problems: The first concerns the problem of deep struggle in case the flat geometry is not awarded on the part covered with the shadow of shadows and outside.
All three problems can be solved geometrically, but because of the possibility that hardware acceleration is directly used, it is a far more elegant implementation using the stencil buffer: 1.
In doing so, the stencil buffer, the pixel of each polygon to be assigned to a specific value for the ground to which they belong.
Edit a stencil buffer and only the pixels that carry a specific value for the selected level.
Unlock buffer for color, and adjust the function of the Z-buffer to allow amendments only where the depth value equal to an existing 3.
For example, the brightness of the spotlight in a dark room with a large presence of dust in the air could be seen illuminating the appropriate volume of space.
Specifically, one way to achieve this effect stencil buffer is to multiply the volume of the shadow, and that as the copies, respectively are scaled according to a geometric series with a low magnification, e.g.,.
