mirror of https://github.com/bsnes-emu/bsnes.git
125 lines
4.0 KiB
Markdown
125 lines
4.0 KiB
Markdown
Most of the consoles higan emulates
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were designed for the low resolution of NTSC televisions,
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and their video output is often chunky and blocky
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by today's standards.
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Shaders customise how a console's video output
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is drawn to the computer screen,
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and can apply just about any effect you can imagine.
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For most [drivers](drivers.md),
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the only shaders available are:
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- **None** draws each computer pixel
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in the same colour as the nearest console pixel.
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This is sometimes called "nearest neighbour scaling",
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and produces crisp, blocky output.
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- **Blur** draws each computer pixel
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as the weighted average colour
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of the four nearest console pixels.
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This is sometimes called "bilinear scaling",
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and hides some of the blockiness
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at the expense of blurring edges.
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However,
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the OpenGL driver supports custom shaders,
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in addition to the above.
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**Note:**
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For technical reasons,
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higan's emulation of certain consoles
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can produce surprising behaviour
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in certain shaders,
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particularly shaders that compare each console pixel
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with its neigbours.
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See [Console-specific Notes](../notes.md) for details.
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# Where to get shaders
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- higan includes some simple example shaders.
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If your copy of higan did not come with shaders,
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you can get them from
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[the unofficial higan repository](https://gitlab.com/higan/higan/tree/master/shaders).
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- [quark-shaders](https://github.com/hizzlekizzle/quark-shaders)
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contains many high-quality shaders for use with higan.
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- You can write your own.
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# How to install shaders
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Make sure the shader you want to install
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is in the correct format:
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it should be a folder whose name ends in `.shader`,
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it should contain a file named `manifest.bml`,
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and probably some `*.fs` or `*.vs` files.
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Place the shader folder inside
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the `Video Shaders` directory
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of your higan installation.
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If you don't have a `Video Shaders` directory,
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create it beside the `*.sys` directories
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like `Game Boy Advance.sys` and `Super Famicom.sys`.
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- On Windows,
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this is probably the directory containing `higan.exe`
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- On Linux,
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this is probably `~/.local/share/higan`
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Launch higan,
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open the Settings menu,
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and choose "Advanced ..."
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to open [the Advanced tab](../interface/higan-config.md#advanced)
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of the Settings dialog.
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Under "Driver Selection",
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make sure "Video" is set to "OpenGL".
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If you changed the video driver,
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you'll need to restart higan
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for the change to take effect.
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Open the Settings menu again,
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choose the "Video Shader" submenu,
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and now the shaders you installed
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should be listed at the bottom of the menu.
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Load a game
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(so you can see the results)
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and switch between shaders
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to see what they do
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and pick your favourite!
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# Notable examples
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The quark-shaders repository
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contains lots of carefully-crafted shaders,
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but some are particularly noteworthy:
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- **AANN** implements "anti-aliased nearest neighbour" scaling.
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If the console's video is not displayed
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at an exact multple of the console's native resolution,
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rounding errors cause normal nearest-neighbour scaling
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to draw some rows and columns wider than others,
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which many people find ugly and distracting.
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This is very common when
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higan's aspect-ratio correction mode
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is enabled.
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AANN uses very slight anti-aliasing
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to hide the rounding errors,
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leaving the overall image as crisp as nearest-neighbour.
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- **Gameboy** emulates the squarish aspect-ratio
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greenish-colours
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and limited palette
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of the original Game Boy.
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At larger scales,
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you can even see the fine gaps between each pixel,
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and the shadow that dark colours would cast
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on the LCD background.
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- **NTSC** performs NTSC encoding,
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bandwidth limiting,
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and NTSC decoding of the video image to recreate
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the colour fringing,
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blurring
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and shimmer
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that most game players would have seen
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on real televisions.
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This is important because
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some games depended on NTSC artifacts
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to display colours outside the console's official palette
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or to create effects like transparency. |