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