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https://github.com/italicsjenga/slang-shaders.git
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281 lines
16 KiB
C
281 lines
16 KiB
C
#define BLUR_FUNCTIONS
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///////////////////////////////// MIT LICENSE ////////////////////////////////
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// Copyright (C) 2014 TroggleMonkey
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to
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// deal in the Software without restriction, including without limitation the
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// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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// sell copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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// IN THE SOFTWARE.
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///////////////////////////////// DESCRIPTION ////////////////////////////////
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// This file provides reusable one-pass and separable (two-pass) blurs.
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// Requires: All blurs share these requirements (dxdy requirement is split):
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// 1.) All requirements of gamma-management.h must be satisfied!
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// 2.) filter_linearN must == "true" in your .cgp preset unless
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// you're using tex2DblurNresize at 1x scale.
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// 3.) mipmap_inputN must == "true" in your .cgp preset if
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// IN.output_size < IN.video_size.
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// 4.) IN.output_size == IN.video_size / pow(2, M), where M is some
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// positive integer. tex2Dblur*resize can resize arbitrarily
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// (and the blur will be done after resizing), but arbitrary
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// resizes "fail" with other blurs due to the way they mix
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// static weights with bilinear sample exploitation.
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// 5.) In general, dxdy should contain the uv pixel spacing:
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// dxdy = (IN.video_size/IN.output_size)/IN.texture_size
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// 6.) For separable blurs (tex2DblurNresize and tex2DblurNfast),
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// zero out the dxdy component in the unblurred dimension:
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// dxdy = vec2(dxdy.x, 0.0) or vec2(0.0, dxdy.y)
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// Many blurs share these requirements:
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// 1.) One-pass blurs require scale_xN == scale_yN or scales > 1.0,
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// or they will blur more in the lower-scaled dimension.
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// 2.) One-pass shared sample blurs require ddx(), ddy(), and
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// tex2Dlod() to be supported by the current Cg profile, and
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// the drivers must support high-quality derivatives.
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// 3.) One-pass shared sample blurs require:
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// tex_uv.w == log2(IN.video_size/IN.output_size).y;
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// Non-wrapper blurs share this requirement:
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// 1.) sigma is the intended standard deviation of the blur
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// Wrapper blurs share this requirement, which is automatically
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// met (unless OVERRIDE_BLUR_STD_DEVS is #defined; see below):
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// 1.) blurN_std_dev must be global static const float values
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// specifying standard deviations for Nx blurs in units
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// of destination pixels
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// Optional: 1.) The including file (or an earlier included file) may
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// optionally #define USE_BINOMIAL_BLUR_STD_DEVS to replace
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// default standard deviations with those matching a binomial
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// distribution. (See below for details/properties.)
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// 2.) The including file (or an earlier included file) may
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// optionally #define OVERRIDE_BLUR_STD_DEVS and override:
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// static const float blur3_std_dev
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// static const float blur4_std_dev
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// static const float blur5_std_dev
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// static const float blur6_std_dev
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// static const float blur7_std_dev
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// static const float blur8_std_dev
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// static const float blur9_std_dev
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// static const float blur10_std_dev
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// static const float blur11_std_dev
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// static const float blur12_std_dev
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// static const float blur17_std_dev
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// static const float blur25_std_dev
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// static const float blur31_std_dev
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// static const float blur43_std_dev
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// 3.) The including file (or an earlier included file) may
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// optionally #define OVERRIDE_ERROR_BLURRING and override:
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// static const float error_blurring
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// This tuning value helps mitigate weighting errors from one-
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// pass shared-sample blurs sharing bilinear samples between
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// fragments. Values closer to 0.0 have "correct" blurriness
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// but allow more artifacts, and values closer to 1.0 blur away
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// artifacts by sampling closer to halfway between texels.
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// UPDATE 6/21/14: The above static constants may now be overridden
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// by non-static uniform constants. This permits exposing blur
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// standard deviations as runtime GUI shader parameters. However,
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// using them keeps weights from being statically computed, and the
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// speed hit depends on the blur: On my machine, uniforms kill over
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// 53% of the framerate with tex2Dblur12x12shared, but they only
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// drop the framerate by about 18% with tex2Dblur11fast.
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// Quality and Performance Comparisons:
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// For the purposes of the following discussion, "no sRGB" means
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// GAMMA_ENCODE_EVERY_FBO is #defined, and "sRGB" means it isn't.
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// 1.) tex2DblurNfast is always faster than tex2DblurNresize.
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// 2.) tex2DblurNresize functions are the only ones that can arbitrarily resize
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// well, because they're the only ones that don't exploit bilinear samples.
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// This also means they're the only functions which can be truly gamma-
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// correct without linear (or sRGB FBO) input, but only at 1x scale.
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// 3.) One-pass shared sample blurs only have a speed advantage without sRGB.
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// They also have some inaccuracies due to their shared-[bilinear-]sample
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// design, which grow increasingly bothersome for smaller blurs and higher-
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// frequency source images (relative to their resolution). I had high
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// hopes for them, but their most realistic use case is limited to quickly
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// reblurring an already blurred input at full resolution. Otherwise:
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// a.) If you're blurring a low-resolution source, you want a better blur.
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// b.) If you're blurring a lower mipmap, you want a better blur.
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// c.) If you're blurring a high-resolution, high-frequency source, you
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// want a better blur.
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// 4.) The one-pass blurs without shared samples grow slower for larger blurs,
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// but they're competitive with separable blurs at 5x5 and smaller, and
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// even tex2Dblur7x7 isn't bad if you're wanting to conserve passes.
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// Here are some framerates from a GeForce 8800GTS. The first pass resizes to
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// viewport size (4x in this test) and linearizes for sRGB codepaths, and the
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// remaining passes perform 6 full blurs. Mipmapped tests are performed at the
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// same scale, so they just measure the cost of mipmapping each FBO (only every
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// other FBO is mipmapped for separable blurs, to mimic realistic usage).
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// Mipmap Neither sRGB+Mipmap sRGB Function
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// 76.0 92.3 131.3 193.7 tex2Dblur3fast
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// 63.2 74.4 122.4 175.5 tex2Dblur3resize
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// 93.7 121.2 159.3 263.2 tex2Dblur3x3
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// 59.7 68.7 115.4 162.1 tex2Dblur3x3resize
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// 63.2 74.4 122.4 175.5 tex2Dblur5fast
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// 49.3 54.8 100.0 132.7 tex2Dblur5resize
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// 59.7 68.7 115.4 162.1 tex2Dblur5x5
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// 64.9 77.2 99.1 137.2 tex2Dblur6x6shared
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// 55.8 63.7 110.4 151.8 tex2Dblur7fast
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// 39.8 43.9 83.9 105.8 tex2Dblur7resize
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// 40.0 44.2 83.2 104.9 tex2Dblur7x7
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// 56.4 65.5 71.9 87.9 tex2Dblur8x8shared
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// 49.3 55.1 99.9 132.5 tex2Dblur9fast
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// 33.3 36.2 72.4 88.0 tex2Dblur9resize
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// 27.8 29.7 61.3 72.2 tex2Dblur9x9
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// 37.2 41.1 52.6 60.2 tex2Dblur10x10shared
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// 44.4 49.5 91.3 117.8 tex2Dblur11fast
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// 28.8 30.8 63.6 75.4 tex2Dblur11resize
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// 33.6 36.5 40.9 45.5 tex2Dblur12x12shared
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// TODO: Fill in benchmarks for new untested blurs.
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// tex2Dblur17fast
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// tex2Dblur25fast
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// tex2Dblur31fast
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// tex2Dblur43fast
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// tex2Dblur3x3resize
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///////////////////////////// SETTINGS MANAGEMENT ////////////////////////////
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// Set static standard deviations, but allow users to override them with their
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// own constants (even non-static uniforms if they're okay with the speed hit):
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#ifndef OVERRIDE_BLUR_STD_DEVS
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// blurN_std_dev values are specified in terms of dxdy strides.
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#ifdef USE_BINOMIAL_BLUR_STD_DEVS
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// By request, we can define standard deviations corresponding to a
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// binomial distribution with p = 0.5 (related to Pascal's triangle).
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// This distribution works such that blurring multiple times should
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// have the same result as a single larger blur. These values are
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// larger than default for blurs up to 6x and smaller thereafter.
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const float blur3_std_dev = 0.84931640625;
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const float blur4_std_dev = 0.84931640625;
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const float blur5_std_dev = 1.0595703125;
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const float blur6_std_dev = 1.06591796875;
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const float blur7_std_dev = 1.17041015625;
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const float blur8_std_dev = 1.1720703125;
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const float blur9_std_dev = 1.2259765625;
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const float blur10_std_dev = 1.21982421875;
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const float blur11_std_dev = 1.25361328125;
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const float blur12_std_dev = 1.2423828125;
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const float blur17_std_dev = 1.27783203125;
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const float blur25_std_dev = 1.2810546875;
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const float blur31_std_dev = 1.28125;
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const float blur43_std_dev = 1.28125;
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#else
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// The defaults are the largest values that keep the largest unused
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// blur term on each side <= 1.0/256.0. (We could get away with more
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// or be more conservative, but this compromise is pretty reasonable.)
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const float blur3_std_dev = 0.62666015625;
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const float blur4_std_dev = 0.66171875;
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const float blur5_std_dev = 0.9845703125;
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const float blur6_std_dev = 1.02626953125;
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const float blur7_std_dev = 1.36103515625;
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const float blur8_std_dev = 1.4080078125;
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const float blur9_std_dev = 1.7533203125;
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const float blur10_std_dev = 1.80478515625;
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const float blur11_std_dev = 2.15986328125;
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const float blur12_std_dev = 2.215234375;
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const float blur17_std_dev = 3.45535583496;
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const float blur25_std_dev = 5.3409576416;
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const float blur31_std_dev = 6.86488037109;
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const float blur43_std_dev = 10.1852050781;
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#endif // USE_BINOMIAL_BLUR_STD_DEVS
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#endif // OVERRIDE_BLUR_STD_DEVS
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#ifndef OVERRIDE_ERROR_BLURRING
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// error_blurring should be in [0.0, 1.0]. Higher values reduce ringing
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// in shared-sample blurs but increase blurring and feature shifting.
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const float error_blurring = 0.5;
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#endif
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// Make a length squared helper macro (for usage with static constants):
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#define LENGTH_SQ(vec) (dot(vec, vec))
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/////////////////////////////////// HELPERS //////////////////////////////////
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vec4 uv2_to_uv4(vec2 tex_uv)
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{
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// Make a vec2 uv offset safe for adding to vec4 tex2Dlod coords:
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return vec4(tex_uv, 0.0, 0.0);
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}
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// Make a length squared helper macro (for usage with static constants):
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#define LENGTH_SQ(vec) (dot(vec, vec))
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float get_fast_gaussian_weight_sum_inv(const float sigma)
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{
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// We can use the Gaussian integral to calculate the asymptotic weight for
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// the center pixel. Since the unnormalized center pixel weight is 1.0,
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// the normalized weight is the same as the weight sum inverse. Given a
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// large enough blur (9+), the asymptotic weight sum is close and faster:
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// center_weight = 0.5 *
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// (erf(0.5/(sigma*sqrt(2.0))) - erf(-0.5/(sigma*sqrt(2.0))))
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// erf(-x) == -erf(x), so we get 0.5 * (2.0 * erf(blah blah)):
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// However, we can get even faster results with curve-fitting. These are
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// also closer than the asymptotic results, because they were constructed
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// from 64 blurs sizes from [3, 131) and 255 equally-spaced sigmas from
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// (0, blurN_std_dev), so the results for smaller sigmas are biased toward
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// smaller blurs. The max error is 0.0031793913.
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// Relative FPS: 134.3 with erf, 135.8 with curve-fitting.
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//static const float temp = 0.5/sqrt(2.0);
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//return erf(temp/sigma);
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return min(exp(exp(0.348348412457428/
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(sigma - 0.0860587260734721))), 0.399334576340352/sigma);
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}
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//////////////////// ARBITRARILY RESIZABLE ONE-PASS BLURS ////////////////////
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vec3 tex2Dblur3x3resize(const sampler2D tex, const vec2 tex_uv,
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const vec2 dxdy, const float sigma)
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{
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// Requires: Global requirements must be met (see file description).
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// Returns: A 3x3 Gaussian blurred mipmapped texture lookup of the
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// resized input.
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// Description:
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// This is the only arbitrarily resizable one-pass blur; tex2Dblur5x5resize
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// would perform like tex2Dblur9x9, MUCH slower than tex2Dblur5resize.
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const float denom_inv = 0.5/(sigma*sigma);
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// Load each sample. We need all 3x3 samples. Quad-pixel communication
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// won't help either: This should perform like tex2Dblur5x5, but sharing a
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// 4x4 sample field would perform more like tex2Dblur8x8shared (worse).
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const vec2 sample4_uv = tex_uv;
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const vec2 dx = vec2(dxdy.x, 0.0);
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const vec2 dy = vec2(0.0, dxdy.y);
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const vec2 sample1_uv = sample4_uv - dy;
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const vec2 sample7_uv = sample4_uv + dy;
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const vec3 sample0 = tex2D_linearize(tex, sample1_uv - dx).rgb;
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const vec3 sample1 = tex2D_linearize(tex, sample1_uv).rgb;
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const vec3 sample2 = tex2D_linearize(tex, sample1_uv + dx).rgb;
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const vec3 sample3 = tex2D_linearize(tex, sample4_uv - dx).rgb;
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const vec3 sample4 = tex2D_linearize(tex, sample4_uv).rgb;
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const vec3 sample5 = tex2D_linearize(tex, sample4_uv + dx).rgb;
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const vec3 sample6 = tex2D_linearize(tex, sample7_uv - dx).rgb;
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const vec3 sample7 = tex2D_linearize(tex, sample7_uv).rgb;
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const vec3 sample8 = tex2D_linearize(tex, sample7_uv + dx).rgb;
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// Statically compute Gaussian sample weights:
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const float w4 = 1.0;
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const float w1_3_5_7 = exp(-LENGTH_SQ(vec2(1.0, 0.0)) * denom_inv);
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const float w0_2_6_8 = exp(-LENGTH_SQ(vec2(1.0, 1.0)) * denom_inv);
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const float weight_sum_inv = 1.0/(w4 + 4.0 * (w1_3_5_7 + w0_2_6_8));
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// Weight and sum the samples:
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const vec3 sum = w4 * sample4 +
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w1_3_5_7 * (sample1 + sample3 + sample5 + sample7) +
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w0_2_6_8 * (sample0 + sample2 + sample6 + sample8);
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return sum * weight_sum_inv;
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}
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// Resizable one-pass blurs:
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vec3 tex2Dblur3x3resize(const sampler2D texture, const vec2 tex_uv,
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const vec2 dxdy)
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{
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return tex2Dblur3x3resize(texture, tex_uv, dxdy, blur3_std_dev);
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} |