mirror of https://github.com/bsnes-emu/bsnes.git
More cleanups.
This commit is contained in:
Tim Allen
parent
afa8ea61c5
commit
c273297577
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@ -1,29 +1,41 @@
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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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were designed for low resolution NTSC televisions,
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and their video output is 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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Video 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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and can clean up and smooth out the original video,
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reproduce the scanlines and blurring of the original display,
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or any other visual effect.
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Most [drivers](drivers.md)
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only support these shaders
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(some only support one or the other):
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The available video shaders are listed in
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the "Video Shaders" submenu of
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[the Settings menu](../interface/higan.md#the-settings-menu).
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Which shaders are available depends on
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[video driver](drivers.md#video) higan is configured to use.
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Most drivers only support these shaders:
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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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- **None**
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draws each computer pixel according to
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the colour of the single nearest console pixel,
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sometimes called "nearest neighbour" scaling.
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This produces unnaturally crisp and blocky images.
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- If you use [aspect correction or non-integral scaling][ac],
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neighbouring console pixels may be drawn
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with a different number of computer pixels due to rounding errors,
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causing a distracting rippling effect.
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- **Blur**
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draws each computer pixel according to
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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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averaging the colours of the four nearest console pixels,
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sometimes called "bilinear" scaling.
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This produces unnaturally blurry images.
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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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[ac]: ../interface/higan-settings.md#video
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In addition to those,
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the OpenGL driver also supports custom shaders.
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**Note:**
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For technical reasons,
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@ -32,9 +44,12 @@ 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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See [Video Shaders and TV-based consoles][vstv] for details.
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# Where to get shaders
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[vstv]: #video-shaders-and-tv-based-consoles
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Where to get custom shaders
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---------------------------
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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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@ -44,7 +59,8 @@ See [Console-specific Notes](../notes.md) for details.
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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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How to install custom shaders
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-----------------------------
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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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@ -68,10 +84,10 @@ 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-settings.md#advanced)
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of the Settings dialog.
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of the Settings window.
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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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If it wasn't already set that way,
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you'll need to restart higan
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for the change to take effect.
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@ -81,31 +97,27 @@ 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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(so you can see the results),
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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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Notable examples
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----------------
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The quark-shaders repository
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The quark-shaders repository mentioned above
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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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This uses anti-aliasing to hide
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the rounding errors often introduced by
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aspect ratio correction
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and non-integral scaling,
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producing an image nearly as crisp as the "None" shader,
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but without the distracting ripple effect.
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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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@ -120,7 +132,85 @@ but some are particularly noteworthy:
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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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Some games depend 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.
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Video Shaders and TV-based consoles
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-----------------------------------
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Simple shaders
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(like "None"
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and the third-party "AANN" shader)
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just blindly scale up the images they're given,
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but sophisticated shaders
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(such as the third-party "xBR" shader)
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try to produce higher-quality output
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by recognising particular patterns,
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like taking three diagonal pixels
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and turning that into a smooth diagonal line.
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These shaders assume that
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each pixel drawn by the game's artists
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becomes a single pixel in the video output they analyze.
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The hand-held consoles that higan emulates
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(and also the Famicom)
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can only output video at one specific resolution,
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so this "one pixel equals one pixel" rule holds true,
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and pattern-based shaders like "xBR" work just fine.
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Unfortunately,
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this is not true for most of the TV-based consoles
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that higan supports.
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The Super Famicom's "normal" video mode
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draws 256 pixels across the width of the screen,
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but the "high resolution" mode draws 512.
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Since Super Famicom games can enable hi-res mode at any time
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(even halfway through a frame),
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higan always renders Super Famicom video output 512 pixels wide,
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just in case.
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This means that in "normal" mode,
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each pixel drawn by the game's artists
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becomes two pixels in the video output,
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breaking the assumption
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that pattern-based shaders are based on.
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The Super Famicom has a similar issue in the vertical direction:
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normally,
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an NTSC-based Super Famicom draws about 240 rows of output every frame,
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sometimes referred to as "240p" video.
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When a game turns on "interlaced" mode,
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it draws the 240 odd-numbered lines of one frame,
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then the 240 even-numbered lines of the next,
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and so forth.
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This is sometimes referred to as "480i" video.
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Although interlaced mode cannot be enabled mid-frame
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like high-resolution mode,
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resolution switching is still complex,
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so higan always draws all 480 lines of video output.
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This means for a normal, non-interlaced game,
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each pixel drawn by the game's artists
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becomes four pixels in the video output
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(two horizontally and two vertically)
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making pattern-based shaders even less useful.
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It also breaks most scanline-emulation shaders,
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since they typically draw a scanline
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for each row of pixels in the video output.
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The Mega Drive has similar problems
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to the Super Famicom.
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It has the same behaviour with interlacing,
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but its high-resolution mode switches
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from 256 pixels across to 320 pixels across.
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Therefore in normal mode,
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each pixel drawn by the game's artists
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becomes five pixels in the video output,
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while in high-resolution mode,
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each pixel drawn by the game's artists
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becomes four pixels in the video output
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(or 10 and 8 pixels in non-interlaced mode).
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The PC Engine does not support an interlaced mode,
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but its horizontal resolution is much more flexible
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than the Super Famicom or Mega Drive,
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and so it has the same problems with shaders as those consoles.
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|
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@ -144,27 +144,8 @@ that aren't technically part of the console itself:
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**Video Shader** controls
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how the low-resolution video output of the emulated console
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is scaled up to suit modern high-resolution displays.
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The availability of items in this submenu depends on
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which video driver higan is using,
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so see [Choosing drivers](../guides/drivers.md) for more information.
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- **None**
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draws each output pixel according to
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the colour of the single nearest input pixel,
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sometimes called "nearest neighbour" scaling.
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This produces unnaturally crisp and blocky images.
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- **Blur**
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draws each output pixel by
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averaging the colours of the four nearest input pixels,
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sometimes called "bilinear" scaling.
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This produces unnaturally blurry images.
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- When using the OpenGL driver,
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an additional item appears in this menu for
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each installed shader.
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See [Using video shaders](../guides/shaders.md)
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for details.
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[Using video shaders](../guides/shaders.md)
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describes all the options in this submenu.
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**Synchronize Audio**
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causes higan to wait for audio playback to complete
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|
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@ -3,87 +3,6 @@ are similar in many ways,
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but some of them do have particular quirks
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that you should be aware of.
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Video Shaders and TV-based consoles
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-----------------------------------
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[Video Shaders](guides/shaders.md)
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customize how higan scales
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the low-resolution video of the emulated console
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up to the high-resolution of the computer display.
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Simple shaders
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(like "None"
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and the third-party "AANN" shader)
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just blindly scale up the images they're given,
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but sophisticated shaders
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(such as the third-party "xBR" shader)
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try to produce higher-quality output
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by recognising particular patterns of pixel,
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like taking three diagonal pixels
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and turning that into a smooth diagonal line.
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|
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These shaders assume that
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each pixel drawn by the game's artists
|
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becomes a single pixel in the video output they analyze.
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Many of the consoles higan emulates
|
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can only output video at one specific resolution,
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so this "one pixel equals one pixel" rule holds true,
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and pattern-based shaders like "xBR" work just fine.
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Unfortunately,
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this is not the case for the Super Famicom.
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The "normal" video mode
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draws 256 pixels across the width of the screen,
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but the "high resolution" mode draws 512.
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Since Super Famicom games can enable hi-res mode at any time
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(even halfway through a frame),
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higan always renders Super Famicom video output 512 pixels wide,
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just in case.
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This means that in "normal" mode,
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each pixel drawn by the game's artists
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becomes two pixels in the video output,
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breaking the assumption
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that pattern-based shaders are based on.
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|
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The Super Famicom has a similar issue in the vertical direction:
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normally,
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an NTSC-based Super Famicom draws about 240 rows of output every frame,
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sometimes referred to as "240p" video.
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When a game turns on "interlaced" mode,
|
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it draws the 240 odd-numbered lines of one frame,
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then the 240 even-numbered lines of the next,
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and so forth.
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This is sometimes referred to as "480i" video.
|
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Although interlaced mode cannot be enabled mid-frame
|
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like high-resolution mode,
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resolution switching is still complex,
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so higan always draws all 480 lines of video output.
|
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This means for a normal, non-interlaced game,
|
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each pixel drawn by the game's artists
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becomes four pixels in the video output
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(two horizontally and two vertically)
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making pattern-based shaders even less useful.
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It also breaks most scanline-emulation shaders,
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since they typically draw a scanline
|
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for each row of pixels in the video output.
|
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|
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The Mega Drive has similar problems
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to the Super Famicom.
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It has the same behaviour with interlacing,
|
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but its high-resolution mode switches
|
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from 256 pixels across to 320 pixels across.
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Therefore in normal mode,
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each pixel drawn by the game's artists
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becomes five pixels in the video output,
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while in high-resolution mode,
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each pixel drawn by the game's artists
|
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becomes four pixels in the video output
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(or 10 and 8 pixels in non-interlaced mode).
|
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|
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The PC Engine does not support an interlaced mode,
|
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but its horizontal resolution is much more flexible
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than the Super Famicom or Mega Drive,
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and so it has the same problems with shaders.
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Music and Sound Effect Volume on the Mega Drive
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-----------------------------------------------
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