This document describes the framebuffer.
The framebuffer is a memory region for temporarily storing data output from the fragment shader.
Values for fragments for which processing by fragment using the blender has ended are stored here.
The table below gives an overview of the three buffers that collectively make up the framebuffer.
Buffer Type | Usage |
---|---|
Color Buffer | Renders fragment values that contain color and alpha values. |
Stencil Buffer | Stores information that limits the area being rendered. This is used during stencil tests. |
Depth Buffer | Stores information about the depth from the camera. This is used during depth tests. |
Several different data recording formats can be specified for each buffer when storing data.
The following figure shows the formats for the color buffer, stencil buffer, and depth buffer.
The number of bits per pixel differs for the format of each buffer making up the framebuffer. For buffers with few bits, the on-screen display system degrades in proportion to how small the buffer allocated in recording memory is.
Note: A format having a total of 32 bits results when using an 8-bit stencil buffer combined with a 24-bit depth buffer.
This section describes anti-aliasing when rendering to the screen.
Anti-aliasing is a method for smoothing outlines when drawing polygons.
You can apply anti-aliasing by having a larger image scale in the frame buffer than in the display buffer and reducing the image when sending it from the frame buffer to the display buffer.
The display buffer is the region of memory where the image output from the framebuffer is stored after the image data have been converted to an actual picture for display on the screen.
It can be secured in VRAM and in device memory.
The table below lists the two available anti-aliasing methods.
Types of Rendering Scaling Factors | Direction anti-aliasing is applied | Required framebuffer size. |
---|---|---|
2 × 1 | Vertical direction of screen. | Results in two times the display buffer. |
2 × 2 | Vertical and horizontal direction of screen. | Results in four times the display buffer. |
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