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bf1b023f12
- A new port of crt-royale. More faithful to original. It uses the same mask textures. - The only thing not ported is the original geometry pass. It was replaced by geom curvature code. - It's configured for 1080p displays. 4k displays need to adjust param mask_triad_size_desired from 3.0 to 4.0. OBS: It's up to you decide if the two versions should be maintained.
570 lines
28 KiB
HLSL
570 lines
28 KiB
HLSL
#ifndef SCANLINE_FUNCTIONS_H
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#define SCANLINE_FUNCTIONS_H
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///////////////////////////// GPL LICENSE NOTICE /////////////////////////////
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// crt-royale: A full-featured CRT shader, with cheese.
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// Copyright (C) 2014 TroggleMonkey <trogglemonkey@gmx.com>
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//
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// This program is free software; you can redistribute it and/or modify it
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// under the terms of the GNU General Public License as published by the Free
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// Software Foundation; either version 2 of the License, or any later version.
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//
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// This program is distributed in the hope that it will be useful, but WITHOUT
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// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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// more details.
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//
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// You should have received a copy of the GNU General Public License along with
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// this program; if not, write to the Free Software Foundation, Inc., 59 Temple
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// Place, Suite 330, Boston, MA 02111-1307 USA
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////////////////////////////////// INCLUDES //////////////////////////////////
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#include "user-settings.fxh"
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#include "derived-settings-and-constants.fxh"
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#include "special-functions.fxh"
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#include "gamma-management.fxh"
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///////////////////////////// SCANLINE FUNCTIONS /////////////////////////////
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float3 get_gaussian_sigma(const float3 color, const float sigma_range)
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{
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// Requires: Globals:
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// 1.) beam_min_sigma and beam_max_sigma are global floats
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// containing the desired minimum and maximum beam standard
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// deviations, for dim and bright colors respectively.
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// 2.) beam_max_sigma must be > 0.0
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// 3.) beam_min_sigma must be in (0.0, beam_max_sigma]
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// 4.) beam_spot_power must be defined as a global float.
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// Parameters:
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// 1.) color is the underlying source color along a scanline
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// 2.) sigma_range = beam_max_sigma - beam_min_sigma; we take
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// sigma_range as a parameter to avoid repeated computation
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// when beam_{min, max}_sigma are runtime shader parameters
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// Optional: Users may set beam_spot_shape_function to 1 to define the
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// inner f(color) subfunction (see below) as:
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// f(color) = sqrt(1.0 - (color - 1.0)*(color - 1.0))
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// Otherwise (technically, if beam_spot_shape_function < 0.5):
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// f(color) = pow(color, beam_spot_power)
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// Returns: The standard deviation of the Gaussian beam for "color:"
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// sigma = beam_min_sigma + sigma_range * f(color)
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// Details/Discussion:
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// The beam's spot shape vaguely resembles an aspect-corrected f() in the
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// range [0, 1] (not quite, but it's related). f(color) = color makes
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// spots look like diamonds, and a spherical function or cube balances
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// between variable width and a soft/realistic shape. A beam_spot_power
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// > 1.0 can produce an ugly spot shape and more initial clipping, but the
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// final shape also differs based on the horizontal resampling filter and
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// the phosphor bloom. For instance, resampling horizontally in nonlinear
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// light and/or with a sharp (e.g. Lanczos) filter will sharpen the spot
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// shape, but a sixth root is still quite soft. A power function (default
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// 1.0/3.0 beam_spot_power) is most flexible, but a fixed spherical curve
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// has the highest variability without an awful spot shape.
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//
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// beam_min_sigma affects scanline sharpness/aliasing in dim areas, and its
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// difference from beam_max_sigma affects beam width variability. It only
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// affects clipping [for pure Gaussians] if beam_spot_power > 1.0 (which is
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// a conservative estimate for a more complex constraint).
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//
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// beam_max_sigma affects clipping and increasing scanline width/softness
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// as color increases. The wider this is, the more scanlines need to be
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// evaluated to avoid distortion. For a pure Gaussian, the max_beam_sigma
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// at which the first unused scanline always has a weight < 1.0/255.0 is:
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// num scanlines = 2, max_beam_sigma = 0.2089; distortions begin ~0.34
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// num scanlines = 3, max_beam_sigma = 0.3879; distortions begin ~0.52
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// num scanlines = 4, max_beam_sigma = 0.5723; distortions begin ~0.70
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// num scanlines = 5, max_beam_sigma = 0.7591; distortions begin ~0.89
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// num scanlines = 6, max_beam_sigma = 0.9483; distortions begin ~1.08
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// Generalized Gaussians permit more leeway here as steepness increases.
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if(beam_spot_shape_function < 0.5)
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{
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// Use a power function:
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return beam_min_sigma.xxx + sigma_range *
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pow(color, beam_spot_power);
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}
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else
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{
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// Use a spherical function:
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const float3 color_minus_1 = color - 1.0.xxx;
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return beam_min_sigma.xxx + sigma_range *
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sqrt(1.0.xxx - color_minus_1*color_minus_1);
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}
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}
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float3 get_generalized_gaussian_beta(const float3 color,
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const float shape_range)
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{
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// Requires: Globals:
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// 1.) beam_min_shape and beam_max_shape are global floats
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// containing the desired min/max generalized Gaussian
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// beta parameters, for dim and bright colors respectively.
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// 2.) beam_max_shape must be >= 2.0
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// 3.) beam_min_shape must be in [2.0, beam_max_shape]
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// 4.) beam_shape_power must be defined as a global float.
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// Parameters:
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// 1.) color is the underlying source color along a scanline
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// 2.) shape_range = beam_max_shape - beam_min_shape; we take
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// shape_range as a parameter to avoid repeated computation
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// when beam_{min, max}_shape are runtime shader parameters
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// Returns: The type-I generalized Gaussian "shape" parameter beta for
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// the given color.
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// Details/Discussion:
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// Beta affects the scanline distribution as follows:
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// a.) beta < 2.0 narrows the peak to a spike with a discontinuous slope
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// b.) beta == 2.0 just degenerates to a Gaussian
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// c.) beta > 2.0 flattens and widens the peak, then drops off more steeply
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// than a Gaussian. Whereas high sigmas widen and soften peaks, high
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// beta widen and sharpen peaks at the risk of aliasing.
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// Unlike high beam_spot_powers, high beam_shape_powers actually soften shape
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// transitions, whereas lower ones sharpen them (at the risk of aliasing).
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return beam_min_shape + shape_range * pow(color, beam_shape_power);
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}
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float3 scanline_gaussian_integral_contrib(const float3 dist,
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const float3 color, const float pixel_height, const float sigma_range)
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{
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// Requires: 1.) dist is the distance of the [potentially separate R/G/B]
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// point(s) from a scanline in units of scanlines, where
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// 1.0 means the sample point straddles the next scanline.
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// 2.) color is the underlying source color along a scanline.
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// 3.) pixel_height is the output pixel height in scanlines.
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// 4.) Requirements of get_gaussian_sigma() must be met.
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// Returns: Return a scanline's light output over a given pixel.
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// Details:
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// The CRT beam profile follows a roughly Gaussian distribution which is
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// wider for bright colors than dark ones. The integral over the full
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// range of a Gaussian function is always 1.0, so we can vary the beam
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// with a standard deviation without affecting brightness. 'x' = distance:
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// gaussian sample = 1/(sigma*sqrt(2*pi)) * e**(-(x**2)/(2*sigma**2))
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// gaussian integral = 0.5 (1.0 + erf(x/(sigma * sqrt(2))))
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// Use a numerical approximation of the "error function" (the Gaussian
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// indefinite integral) to find the definite integral of the scanline's
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// average brightness over a given pixel area. Even if curved coords were
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// used in this pass, a flat scalar pixel height works almost as well as a
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// pixel height computed from a full pixel-space to scanline-space matrix.
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const float3 sigma = get_gaussian_sigma(color, sigma_range);
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const float3 ph_offset = (pixel_height.xxx) * 0.5;
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const float3 denom_inv = 1.0/(sigma*sqrt(2.0));
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const float3 integral_high = erf((dist + ph_offset)*denom_inv);
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const float3 integral_low = erf((dist - ph_offset)*denom_inv);
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return color * 0.5*(integral_high - integral_low)/pixel_height;
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}
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float3 scanline_generalized_gaussian_integral_contrib(const float3 dist,
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const float3 color, const float pixel_height, const float sigma_range,
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const float shape_range)
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{
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// Requires: 1.) Requirements of scanline_gaussian_integral_contrib()
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// must be met.
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// 2.) Requirements of get_gaussian_sigma() must be met.
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// 3.) Requirements of get_generalized_gaussian_beta() must be
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// met.
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// Returns: Return a scanline's light output over a given pixel.
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// A generalized Gaussian distribution allows the shape (beta) to vary
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// as well as the width (alpha). "gamma" refers to the gamma function:
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// generalized sample =
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// beta/(2*alpha*gamma(1/beta)) * e**(-(|x|/alpha)**beta)
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// ligamma(s, z) is the lower incomplete gamma function, for which we only
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// implement two of four branches (because we keep 1/beta <= 0.5):
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// generalized integral = 0.5 + 0.5* sign(x) *
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// ligamma(1/beta, (|x|/alpha)**beta)/gamma(1/beta)
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// See get_generalized_gaussian_beta() for a discussion of beta.
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// We base alpha on the intended Gaussian sigma, but it only strictly
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// models models standard deviation at beta == 2, because the standard
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// deviation depends on both alpha and beta (keeping alpha independent is
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// faster and preserves intuitive behavior and a full spectrum of results).
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const float3 alpha = sqrt(2.0) * get_gaussian_sigma(color, sigma_range);
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const float3 beta = get_generalized_gaussian_beta(color, shape_range);
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const float3 alpha_inv = 1.0.xxx/alpha;
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const float3 s = 1.0.xxx/beta;
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const float3 ph_offset = (pixel_height.xxx) * 0.5;
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// Pass beta to gamma_impl to avoid repeated divides. Similarly pass
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// beta (i.e. 1/s) and 1/gamma(s) to normalized_ligamma_impl.
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const float3 gamma_s_inv = 1.0.xxx/gamma_impl(s, beta);
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const float3 dist1 = dist + ph_offset;
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const float3 dist0 = dist - ph_offset;
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const float3 integral_high = sign(dist1) * normalized_ligamma_impl(
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s, pow(abs(dist1)*alpha_inv, beta), beta, gamma_s_inv);
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const float3 integral_low = sign(dist0) * normalized_ligamma_impl(
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s, pow(abs(dist0)*alpha_inv, beta), beta, gamma_s_inv);
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return color * 0.5*(integral_high - integral_low)/pixel_height;
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}
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float3 scanline_gaussian_sampled_contrib(const float3 dist, const float3 color,
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const float pixel_height, const float sigma_range)
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{
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// See scanline_gaussian integral_contrib() for detailed comments!
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// gaussian sample = 1/(sigma*sqrt(2*pi)) * e**(-(x**2)/(2*sigma**2))
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const float3 sigma = get_gaussian_sigma(color, sigma_range);
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// Avoid repeated divides:
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const float3 sigma_inv = 1.0.xxx/sigma;
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const float3 inner_denom_inv = 0.5 * sigma_inv * sigma_inv;
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const float3 outer_denom_inv = sigma_inv/sqrt(2.0*pi);
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if(beam_antialias_level > 0.5)
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{
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// Sample 1/3 pixel away in each direction as well:
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const float3 sample_offset = pixel_height.xxx/3.0;
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const float3 dist2 = dist + sample_offset;
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const float3 dist3 = abs(dist - sample_offset);
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// Average three pure Gaussian samples:
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const float3 scale = color/3.0 * outer_denom_inv;
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const float3 weight1 = exp(-(dist*dist)*inner_denom_inv);
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const float3 weight2 = exp(-(dist2*dist2)*inner_denom_inv);
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const float3 weight3 = exp(-(dist3*dist3)*inner_denom_inv);
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return scale * (weight1 + weight2 + weight3);
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}
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else
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{
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return color*exp(-(dist*dist)*inner_denom_inv)*outer_denom_inv;
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}
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}
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float3 scanline_generalized_gaussian_sampled_contrib(const float3 dist,
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const float3 color, const float pixel_height, const float sigma_range,
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const float shape_range)
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{
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// See scanline_generalized_gaussian_integral_contrib() for details!
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// generalized sample =
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// beta/(2*alpha*gamma(1/beta)) * e**(-(|x|/alpha)**beta)
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const float3 alpha = sqrt(2.0) * get_gaussian_sigma(color, sigma_range);
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const float3 beta = get_generalized_gaussian_beta(color, shape_range);
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// Avoid repeated divides:
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const float3 alpha_inv = 1.0.xxx/alpha;
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const float3 beta_inv = 1.0.xxx/beta;
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const float3 scale = color * beta * 0.5 * alpha_inv /
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gamma_impl(beta_inv, beta);
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if(beam_antialias_level > 0.5)
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{
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// Sample 1/3 pixel closer to and farther from the scanline too.
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const float3 sample_offset = pixel_height.xxx/3.0;
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const float3 dist2 = dist + sample_offset;
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const float3 dist3 = abs(dist - sample_offset);
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// Average three generalized Gaussian samples:
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const float3 weight1 = exp(-pow(abs(dist*alpha_inv), beta));
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const float3 weight2 = exp(-pow(abs(dist2*alpha_inv), beta));
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const float3 weight3 = exp(-pow(abs(dist3*alpha_inv), beta));
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return scale/3.0 * (weight1 + weight2 + weight3);
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}
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else
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{
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return scale * exp(-pow(abs(dist*alpha_inv), beta));
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}
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}
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float3 scanline_contrib(float3 dist, float3 color,
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float pixel_height, const float sigma_range, const float shape_range)
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{
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// Requires: 1.) Requirements of scanline_gaussian_integral_contrib()
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// must be met.
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// 2.) Requirements of get_gaussian_sigma() must be met.
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// 3.) Requirements of get_generalized_gaussian_beta() must be
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// met.
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// Returns: Return a scanline's light output over a given pixel, using
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// a generalized or pure Gaussian distribution and sampling or
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// integrals as desired by user codepath choices.
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if(beam_generalized_gaussian)
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{
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if(beam_antialias_level > 1.5)
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{
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return scanline_generalized_gaussian_integral_contrib(
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dist, color, pixel_height, sigma_range, shape_range);
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}
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else
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{
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return scanline_generalized_gaussian_sampled_contrib(
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dist, color, pixel_height, sigma_range, shape_range);
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}
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}
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else
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{
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if(beam_antialias_level > 1.5)
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{
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return scanline_gaussian_integral_contrib(
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dist, color, pixel_height, sigma_range);
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}
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else
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{
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return scanline_gaussian_sampled_contrib(
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dist, color, pixel_height, sigma_range);
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}
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}
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}
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float3 get_raw_interpolated_color(const float3 color0,
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const float3 color1, const float3 color2, const float3 color3,
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const float4 weights)
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{
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// Use max to avoid bizarre artifacts from negative colors:
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return max(mul(weights, float4x3(color0, color1, color2, color3)), 0.0);
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}
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float3 get_interpolated_linear_color(const float3 color0, const float3 color1,
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const float3 color2, const float3 color3, const float4 weights)
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{
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// Requires: 1.) Requirements of include/gamma-management.h must be met:
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// intermediate_gamma must be globally defined, and input
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// colors are interpreted as linear RGB unless you #define
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// GAMMA_ENCODE_EVERY_FBO (in which case they are
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// interpreted as gamma-encoded with intermediate_gamma).
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// 2.) color0-3 are colors sampled from a texture with tex2D().
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// They are interpreted as defined in requirement 1.
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// 3.) weights contains weights for each color, summing to 1.0.
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// 4.) beam_horiz_linear_rgb_weight must be defined as a global
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// float in [0.0, 1.0] describing how much blending should
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// be done in linear RGB (rest is gamma-corrected RGB).
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// 5.) RUNTIME_SCANLINES_HORIZ_FILTER_COLORSPACE must be #defined
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// if beam_horiz_linear_rgb_weight is anything other than a
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// static constant, or we may try branching at runtime
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// without dynamic branches allowed (slow).
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// Returns: Return an interpolated color lookup between the four input
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// colors based on the weights in weights. The final color will
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// be a linear RGB value, but the blending will be done as
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// indicated above.
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const float intermediate_gamma = get_intermediate_gamma();
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// Branch if beam_horiz_linear_rgb_weight is static (for free) or if the
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// profile allows dynamic branches (faster than computing extra pows):
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#ifndef RUNTIME_SCANLINES_HORIZ_FILTER_COLORSPACE
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#define SCANLINES_BRANCH_FOR_LINEAR_RGB_WEIGHT
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#else
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#ifdef DRIVERS_ALLOW_DYNAMIC_BRANCHES
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#define SCANLINES_BRANCH_FOR_LINEAR_RGB_WEIGHT
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#endif
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#endif
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#ifdef SCANLINES_BRANCH_FOR_LINEAR_RGB_WEIGHT
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// beam_horiz_linear_rgb_weight is static, so we can branch:
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#ifdef GAMMA_ENCODE_EVERY_FBO
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const float3 gamma_mixed_color = pow(get_raw_interpolated_color(
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color0, color1, color2, color3, weights), intermediate_gamma);
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if(beam_horiz_linear_rgb_weight > 0.0)
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{
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const float3 linear_mixed_color = get_raw_interpolated_color(
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pow(color0, intermediate_gamma),
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pow(color1, intermediate_gamma),
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pow(color2, intermediate_gamma),
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pow(color3, intermediate_gamma),
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weights);
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return lerp(gamma_mixed_color, linear_mixed_color,
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beam_horiz_linear_rgb_weight);
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}
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else
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{
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return gamma_mixed_color;
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}
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#else
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const float3 linear_mixed_color = get_raw_interpolated_color(
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color0, color1, color2, color3, weights);
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if(beam_horiz_linear_rgb_weight < 1.0)
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{
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const float3 gamma_mixed_color = get_raw_interpolated_color(
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pow(color0, 1.0/intermediate_gamma),
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pow(color1, 1.0/intermediate_gamma),
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pow(color2, 1.0/intermediate_gamma),
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pow(color3, 1.0/intermediate_gamma),
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weights);
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return lerp(gamma_mixed_color, linear_mixed_color,
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beam_horiz_linear_rgb_weight);
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}
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else
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{
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return linear_mixed_color;
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}
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#endif // GAMMA_ENCODE_EVERY_FBO
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#else
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#ifdef GAMMA_ENCODE_EVERY_FBO
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// Inputs: color0-3 are colors in gamma-encoded RGB.
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const float3 gamma_mixed_color = pow(get_raw_interpolated_color(
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color0, color1, color2, color3, weights), intermediate_gamma);
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const float3 linear_mixed_color = get_raw_interpolated_color(
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pow(color0, intermediate_gamma),
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pow(color1, intermediate_gamma),
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pow(color2, intermediate_gamma),
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pow(color3, intermediate_gamma),
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weights);
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return lerp(gamma_mixed_color, linear_mixed_color,
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beam_horiz_linear_rgb_weight);
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#else
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// Inputs: color0-3 are colors in linear RGB.
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const float3 linear_mixed_color = get_raw_interpolated_color(
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color0, color1, color2, color3, weights);
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const float3 gamma_mixed_color = get_raw_interpolated_color(
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pow(color0, 1.0/intermediate_gamma),
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pow(color1, 1.0/intermediate_gamma),
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pow(color2, 1.0/intermediate_gamma),
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pow(color3, 1.0/intermediate_gamma),
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weights);
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return lerp(gamma_mixed_color, linear_mixed_color,
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beam_horiz_linear_rgb_weight);
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#endif // GAMMA_ENCODE_EVERY_FBO
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#endif // SCANLINES_BRANCH_FOR_LINEAR_RGB_WEIGHT
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|
}
|
|
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float3 get_scanline_color(const sampler2D Source, const float2 scanline_uv,
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|
const float2 uv_step_x, const float4 weights)
|
|
{
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|
// Requires: 1.) scanline_uv must be vertically snapped to the caller's
|
|
// desired line or scanline and horizontally snapped to the
|
|
// texel just left of the output pixel (color1)
|
|
// 2.) uv_step_x must contain the horizontal uv distance
|
|
// between texels.
|
|
// 3.) weights must contain interpolation filter weights for
|
|
// color0, color1, color2, and color3, where color1 is just
|
|
// left of the output pixel.
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|
// Returns: Return a horizontally interpolated texture lookup using 2-4
|
|
// nearby texels, according to weights and the conventions of
|
|
// get_interpolated_linear_color().
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|
// We can ignore the outside texture lookups for Quilez resampling.
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|
const float3 color1 = tex2D(Source, scanline_uv).rgb;
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|
const float3 color2 = tex2D(Source, scanline_uv + uv_step_x).rgb;
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float3 color0 = 0.0.xxx;
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|
float3 color3 = 0.0.xxx;
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if(beam_horiz_filter > 0.5)
|
|
{
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|
color0 = tex2D(Source, scanline_uv - uv_step_x).rgb;
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|
color3 = tex2D(Source, scanline_uv + 2.0 * uv_step_x).rgb;
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|
}
|
|
// Sample the texture as-is, whether it's linear or gamma-encoded:
|
|
// get_interpolated_linear_color() will handle the difference.
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|
return get_interpolated_linear_color(color0, color1, color2, color3, weights);
|
|
}
|
|
|
|
float3 sample_single_scanline_horizontal(const sampler2D Source,
|
|
const float2 tex_uv, const float2 texture_size,
|
|
const float2 texture_size_inv)
|
|
{
|
|
// TODO: Add function requirements.
|
|
// Snap to the previous texel and get sample dists from 2/4 nearby texels:
|
|
const float2 curr_texel = tex_uv * texture_size;
|
|
// Use under_half to fix a rounding bug right around exact texel locations.
|
|
const float2 prev_texel =
|
|
floor(curr_texel - under_half.xx) + 0.5.xx;
|
|
const float2 prev_texel_hor = float2(prev_texel.x, curr_texel.y);
|
|
const float2 prev_texel_hor_uv = prev_texel_hor * texture_size_inv;
|
|
const float prev_dist = curr_texel.x - prev_texel_hor.x;
|
|
const float4 sample_dists = float4(1.0 + prev_dist, prev_dist,
|
|
1.0 - prev_dist, 2.0 - prev_dist);
|
|
// Get Quilez, Lanczos2, or Gaussian resize weights for 2/4 nearby texels:
|
|
float4 weights;
|
|
if(beam_horiz_filter < 0.5)
|
|
{
|
|
// Quilez:
|
|
const float x = sample_dists.y;
|
|
const float w2 = x*x*x*(x*(x*6.0 - 15.0) + 10.0);
|
|
weights = float4(0.0, 1.0 - w2, w2, 0.0);
|
|
}
|
|
else if(beam_horiz_filter < 1.5)
|
|
{
|
|
// Gaussian:
|
|
float inner_denom_inv = 1.0/(2.0*beam_horiz_sigma*beam_horiz_sigma);
|
|
weights = exp(-(sample_dists*sample_dists)*inner_denom_inv);
|
|
}
|
|
else
|
|
{
|
|
// Lanczos2:
|
|
const float4 pi_dists = FIX_ZERO(sample_dists * pi);
|
|
weights = 2.0 * sin(pi_dists) * sin(pi_dists * 0.5) /
|
|
(pi_dists * pi_dists);
|
|
}
|
|
// Ensure the weight sum == 1.0:
|
|
const float4 final_weights = weights/dot(weights, 1.0.xxxx);
|
|
// Get the interpolated horizontal scanline color:
|
|
const float2 uv_step_x = float2(texture_size_inv.x, 0.0);
|
|
return get_scanline_color(
|
|
Source, prev_texel_hor_uv, uv_step_x, final_weights);
|
|
}
|
|
|
|
float3 sample_rgb_scanline_horizontal(const sampler2D Source,
|
|
const float2 tex_uv, const float2 texture_size,
|
|
const float2 texture_size_inv)
|
|
{
|
|
// TODO: Add function requirements.
|
|
// Rely on a helper to make convergence easier.
|
|
if(beam_misconvergence)
|
|
{
|
|
const float3 convergence_offsets_rgb =
|
|
get_convergence_offsets_x_vector();
|
|
const float3 offset_u_rgb =
|
|
convergence_offsets_rgb * texture_size_inv.xxx;
|
|
const float2 scanline_uv_r = tex_uv - float2(offset_u_rgb.r, 0.0);
|
|
const float2 scanline_uv_g = tex_uv - float2(offset_u_rgb.g, 0.0);
|
|
const float2 scanline_uv_b = tex_uv - float2(offset_u_rgb.b, 0.0);
|
|
const float3 sample_r = sample_single_scanline_horizontal(
|
|
Source, scanline_uv_r, texture_size, texture_size_inv);
|
|
const float3 sample_g = sample_single_scanline_horizontal(
|
|
Source, scanline_uv_g, texture_size, texture_size_inv);
|
|
const float3 sample_b = sample_single_scanline_horizontal(
|
|
Source, scanline_uv_b, texture_size, texture_size_inv);
|
|
return float3(sample_r.r, sample_g.g, sample_b.b);
|
|
}
|
|
else
|
|
{
|
|
return sample_single_scanline_horizontal(Source, tex_uv, texture_size,
|
|
texture_size_inv);
|
|
}
|
|
}
|
|
|
|
float2 get_last_scanline_uv(const float2 tex_uv, const float2 texture_size,
|
|
const float2 texture_size_inv, const float2 il_step_multiple,
|
|
const float frame_count, out float dist)
|
|
{
|
|
// Compute texture coords for the last/upper scanline, accounting for
|
|
// interlacing: With interlacing, only consider even/odd scanlines every
|
|
// other frame. Top-field first (TFF) order puts even scanlines on even
|
|
// frames, and BFF order puts them on odd frames. Texels are centered at:
|
|
// frac(tex_uv * texture_size) == x.5
|
|
// Caution: If these coordinates ever seem incorrect, first make sure it's
|
|
// not because anisotropic filtering is blurring across field boundaries.
|
|
// Note: TFF/BFF won't matter for sources that double-weave or similar.
|
|
const float field_offset = floor(il_step_multiple.y * 0.75) *
|
|
fmod(frame_count + float(interlace_bff), 2.0);
|
|
const float2 curr_texel = tex_uv * texture_size;
|
|
// Use under_half to fix a rounding bug right around exact texel locations.
|
|
// This causes an insane bug on duckstation, so it's disabled here. (Hyllian, 2024)
|
|
// const float2 prev_texel_num = floor(curr_texel - under_half.xx);
|
|
const float2 prev_texel_num = curr_texel;
|
|
const float wrong_field = fmod(
|
|
prev_texel_num.y + field_offset, il_step_multiple.y);
|
|
const float2 scanline_texel_num = prev_texel_num - float2(0.0, wrong_field);
|
|
// Snap to the center of the previous scanline in the current field:
|
|
const float2 scanline_texel = scanline_texel_num + 0.5.xx;
|
|
const float2 scanline_uv = scanline_texel * texture_size_inv;
|
|
// Save the sample's distance from the scanline, in units of scanlines:
|
|
dist = (curr_texel.y - scanline_texel.y)/il_step_multiple.y;
|
|
return scanline_uv;
|
|
}
|
|
|
|
bool is_interlaced(float num_lines)
|
|
{
|
|
// Detect interlacing based on the number of lines in the source.
|
|
if(interlace_detect)
|
|
{
|
|
// NTSC: 525 lines, 262.5/field; 486 active (2 half-lines), 243/field
|
|
// NTSC Emulators: Typically 224 or 240 lines
|
|
// PAL: 625 lines, 312.5/field; 576 active (typical), 288/field
|
|
// PAL Emulators: ?
|
|
// ATSC: 720p, 1080i, 1080p
|
|
// Where do we place our cutoffs? Assumptions:
|
|
// 1.) We only need to care about active lines.
|
|
// 2.) Anything > 288 and <= 576 lines is probably interlaced.
|
|
// 3.) Anything > 576 lines is probably not interlaced...
|
|
// 4.) ...except 1080 lines, which is a crapshoot (user decision).
|
|
// 5.) Just in case the main program uses calculated video sizes,
|
|
// we should nudge the float thresholds a bit.
|
|
const bool sd_interlace = ((num_lines > 288.5) && (num_lines < 576.5));
|
|
const bool hd_interlace = interlace_1080i ?
|
|
((num_lines > 1079.5) && (num_lines < 1080.5)) :
|
|
false;
|
|
return (sd_interlace || hd_interlace);
|
|
}
|
|
else
|
|
{
|
|
return false;
|
|
}
|
|
}
|
|
|
|
|
|
#endif // SCANLINE_FUNCTIONS_H
|
|
|