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mpv/video/out/gpu/video_shaders.c

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/*
* This file is part of mpv.
*
* mpv is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* mpv is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with mpv. If not, see <http://www.gnu.org/licenses/>.
*/
#include <math.h>
#include "video_shaders.h"
#include "video.h"
#define GLSL(x) gl_sc_add(sc, #x "\n");
#define GLSLF(...) gl_sc_addf(sc, __VA_ARGS__)
#define GLSLH(x) gl_sc_hadd(sc, #x "\n");
#define GLSLHF(...) gl_sc_haddf(sc, __VA_ARGS__)
// Set up shared/commonly used variables and macros
void sampler_prelude(struct gl_shader_cache *sc, int tex_num)
{
GLSLF("#undef tex\n");
GLSLF("#undef texmap\n");
GLSLF("#define tex texture%d\n", tex_num);
GLSLF("#define texmap texmap%d\n", tex_num);
GLSLF("vec2 pos = texcoord%d;\n", tex_num);
GLSLF("vec2 size = texture_size%d;\n", tex_num);
GLSLF("vec2 pt = pixel_size%d;\n", tex_num);
}
static void pass_sample_separated_get_weights(struct gl_shader_cache *sc,
struct scaler *scaler)
{
gl_sc_uniform_texture(sc, "lut", scaler->lut);
GLSLF("float ypos = LUT_POS(fcoord, %d.0);\n", scaler->lut_size);
int N = scaler->kernel->size;
int width = (N + 3) / 4; // round up
GLSLF("float weights[%d];\n", N);
for (int i = 0; i < N; i++) {
if (i % 4 == 0)
GLSLF("c = texture(lut, vec2(%f, ypos));\n", (i / 4 + 0.5) / width);
GLSLF("weights[%d] = c[%d];\n", i, i % 4);
}
}
// Handle a single pass (either vertical or horizontal). The direction is given
// by the vector (d_x, d_y). If the vector is 0, then planar interpolation is
// used instead (samples from texture0 through textureN)
void pass_sample_separated_gen(struct gl_shader_cache *sc, struct scaler *scaler,
int d_x, int d_y)
{
int N = scaler->kernel->size;
bool use_ar = scaler->conf.antiring > 0;
bool planar = d_x == 0 && d_y == 0;
GLSL(color = vec4(0.0);)
GLSLF("{\n");
if (!planar) {
GLSLF("vec2 dir = vec2(%d.0, %d.0);\n", d_x, d_y);
GLSL(pt *= dir;)
GLSL(float fcoord = dot(fract(pos * size - vec2(0.5)), dir);)
GLSLF("vec2 base = pos - fcoord * pt - pt * vec2(%d.0);\n", N / 2 - 1);
}
GLSL(vec4 c;)
if (use_ar) {
GLSL(vec4 hi = vec4(0.0);)
GLSL(vec4 lo = vec4(1.0);)
}
pass_sample_separated_get_weights(sc, scaler);
GLSLF("// scaler samples\n");
for (int n = 0; n < N; n++) {
if (planar) {
GLSLF("c = texture(texture%d, texcoord%d);\n", n, n);
} else {
GLSLF("c = texture(tex, base + pt * vec2(%d.0));\n", n);
}
GLSLF("color += vec4(weights[%d]) * c;\n", n);
if (use_ar && (n == N/2-1 || n == N/2)) {
GLSL(lo = min(lo, c);)
GLSL(hi = max(hi, c);)
}
}
if (use_ar)
GLSLF("color = mix(color, clamp(color, lo, hi), %f);\n",
scaler->conf.antiring);
GLSLF("}\n");
}
// Subroutine for computing and adding an individual texel contribution
// If planar is false, samples directly
// If planar is true, takes the pixel from inX[idx] where X is the component and
// `idx` must be defined by the caller
static void polar_sample(struct gl_shader_cache *sc, struct scaler *scaler,
int x, int y, int components, bool planar)
{
double radius = scaler->kernel->f.radius * scaler->kernel->filter_scale;
double radius_cutoff = scaler->kernel->radius_cutoff;
// Since we can't know the subpixel position in advance, assume a
// worst case scenario
int yy = y > 0 ? y-1 : y;
int xx = x > 0 ? x-1 : x;
double dmax = sqrt(xx*xx + yy*yy);
// Skip samples definitely outside the radius
if (dmax >= radius_cutoff)
return;
GLSLF("d = length(vec2(%d.0, %d.0) - fcoord);\n", x, y);
// Check for samples that might be skippable
bool maybe_skippable = dmax >= radius_cutoff - M_SQRT2;
if (maybe_skippable)
GLSLF("if (d < %f) {\n", radius_cutoff);
// get the weight for this pixel
if (scaler->lut->params.dimensions == 1) {
GLSLF("w = tex1D(lut, LUT_POS(d * 1.0/%f, %d.0)).r;\n",
radius, scaler->lut_size);
} else {
GLSLF("w = texture(lut, vec2(0.5, LUT_POS(d * 1.0/%f, %d.0))).r;\n",
radius, scaler->lut_size);
}
GLSL(wsum += w;)
if (planar) {
for (int n = 0; n < components; n++)
GLSLF("color[%d] += w * in%d[idx];\n", n, n);
} else {
GLSLF("in0 = texture(tex, base + pt * vec2(%d.0, %d.0));\n", x, y);
GLSL(color += vec4(w) * in0;)
}
if (maybe_skippable)
GLSLF("}\n");
}
void pass_sample_polar(struct gl_shader_cache *sc, struct scaler *scaler,
int components, bool sup_gather)
{
GLSL(color = vec4(0.0);)
GLSLF("{\n");
GLSL(vec2 fcoord = fract(pos * size - vec2(0.5));)
GLSL(vec2 base = pos - fcoord * pt;)
GLSLF("float w, d, wsum = 0.0;\n");
for (int n = 0; n < components; n++)
GLSLF("vec4 in%d;\n", n);
GLSL(int idx;)
gl_sc_uniform_texture(sc, "lut", scaler->lut);
GLSLF("// scaler samples\n");
int bound = ceil(scaler->kernel->radius_cutoff);
for (int y = 1-bound; y <= bound; y += 2) {
for (int x = 1-bound; x <= bound; x += 2) {
// First we figure out whether it's more efficient to use direct
// sampling or gathering. The problem is that gathering 4 texels
// only to discard some of them is very wasteful, so only do it if
// we suspect it will be a win rather than a loss. This is the case
// exactly when all four texels are within bounds
bool use_gather = sqrt(x*x + y*y) < scaler->kernel->radius_cutoff;
if (!sup_gather)
use_gather = false;
if (use_gather) {
// Gather the four surrounding texels simultaneously
for (int n = 0; n < components; n++) {
GLSLF("in%d = textureGatherOffset(tex, base, "
"ivec2(%d, %d), %d);\n", n, x, y, n);
}
// Mix in all of the points with their weights
for (int p = 0; p < 4; p++) {
// The four texels are gathered counterclockwise starting
// from the bottom left
static const int xo[4] = {0, 1, 1, 0};
static const int yo[4] = {1, 1, 0, 0};
if (x+xo[p] > bound || y+yo[p] > bound)
continue;
GLSLF("idx = %d;\n", p);
polar_sample(sc, scaler, x+xo[p], y+yo[p], components, true);
}
} else {
// switch to direct sampling instead, for efficiency/compatibility
for (int yy = y; yy <= bound && yy <= y+1; yy++) {
for (int xx = x; xx <= bound && xx <= x+1; xx++)
polar_sample(sc, scaler, xx, yy, components, false);
}
}
}
}
GLSL(color = color / vec4(wsum);)
GLSLF("}\n");
}
// bw/bh: block size
// iw/ih: input size (pre-calculated to fit all required texels)
void pass_compute_polar(struct gl_shader_cache *sc, struct scaler *scaler,
int components, int bw, int bh, int iw, int ih)
{
int bound = ceil(scaler->kernel->radius_cutoff);
int offset = bound - 1; // padding top/left
GLSL(color = vec4(0.0);)
GLSLF("{\n");
GLSL(vec2 wpos = texmap(gl_WorkGroupID * gl_WorkGroupSize);)
GLSL(vec2 wbase = wpos - pt * fract(wpos * size - vec2(0.5));)
GLSL(vec2 fcoord = fract(pos * size - vec2(0.5));)
GLSL(vec2 base = pos - pt * fcoord;)
GLSL(ivec2 rel = ivec2(round((base - wbase) * size));)
GLSL(int idx;)
GLSLF("float w, d, wsum = 0.0;\n");
gl_sc_uniform_texture(sc, "lut", scaler->lut);
// Load all relevant texels into shmem
for (int c = 0; c < components; c++)
GLSLHF("shared float in%d[%d];\n", c, ih * iw);
GLSL(vec4 c;)
GLSLF("for (int y = int(gl_LocalInvocationID.y); y < %d; y += %d) {\n", ih, bh);
GLSLF("for (int x = int(gl_LocalInvocationID.x); x < %d; x += %d) {\n", iw, bw);
GLSLF("c = texture(tex, wbase + pt * vec2(x - %d, y - %d));\n", offset, offset);
for (int c = 0; c < components; c++)
GLSLF("in%d[%d * y + x] = c[%d];\n", c, iw, c);
GLSLF("}}\n");
GLSL(groupMemoryBarrier();)
GLSL(barrier();)
// Dispatch the actual samples
GLSLF("// scaler samples\n");
for (int y = 1-bound; y <= bound; y++) {
for (int x = 1-bound; x <= bound; x++) {
GLSLF("idx = %d * rel.y + rel.x + %d;\n", iw,
iw * (y + offset) + x + offset);
polar_sample(sc, scaler, x, y, components, true);
}
}
GLSL(color = color / vec4(wsum);)
GLSLF("}\n");
}
static void bicubic_calcweights(struct gl_shader_cache *sc, const char *t, const char *s)
{
// Explanation of how bicubic scaling with only 4 texel fetches is done:
// http://www.mate.tue.nl/mate/pdfs/10318.pdf
// 'Efficient GPU-Based Texture Interpolation using Uniform B-Splines'
// Explanation why this algorithm normally always blurs, even with unit
// scaling:
// http://bigwww.epfl.ch/preprints/ruijters1001p.pdf
// 'GPU Prefilter for Accurate Cubic B-spline Interpolation'
GLSLF("vec4 %s = vec4(-0.5, 0.1666, 0.3333, -0.3333) * %s"
" + vec4(1, 0, -0.5, 0.5);\n", t, s);
GLSLF("%s = %s * %s + vec4(0, 0, -0.5, 0.5);\n", t, t, s);
GLSLF("%s = %s * %s + vec4(-0.6666, 0, 0.8333, 0.1666);\n", t, t, s);
GLSLF("%s.xy *= vec2(1, 1) / vec2(%s.z, %s.w);\n", t, t, t);
GLSLF("%s.xy += vec2(1.0 + %s, 1.0 - %s);\n", t, s, s);
}
void pass_sample_bicubic_fast(struct gl_shader_cache *sc)
{
GLSLF("{\n");
GLSL(vec2 fcoord = fract(pos * size + vec2(0.5, 0.5));)
bicubic_calcweights(sc, "parmx", "fcoord.x");
bicubic_calcweights(sc, "parmy", "fcoord.y");
GLSL(vec4 cdelta;)
GLSL(cdelta.xz = parmx.rg * vec2(-pt.x, pt.x);)
GLSL(cdelta.yw = parmy.rg * vec2(-pt.y, pt.y);)
// first y-interpolation
GLSL(vec4 ar = texture(tex, pos + cdelta.xy);)
GLSL(vec4 ag = texture(tex, pos + cdelta.xw);)
GLSL(vec4 ab = mix(ag, ar, parmy.b);)
// second y-interpolation
GLSL(vec4 br = texture(tex, pos + cdelta.zy);)
GLSL(vec4 bg = texture(tex, pos + cdelta.zw);)
GLSL(vec4 aa = mix(bg, br, parmy.b);)
// x-interpolation
GLSL(color = mix(aa, ab, parmx.b);)
GLSLF("}\n");
}
void pass_sample_oversample(struct gl_shader_cache *sc, struct scaler *scaler,
int w, int h)
{
GLSLF("{\n");
GLSL(vec2 pos = pos - vec2(0.5) * pt;) // round to nearest
GLSL(vec2 fcoord = fract(pos * size - vec2(0.5));)
// Determine the mixing coefficient vector
gl_sc_uniform_vec2(sc, "output_size", (float[2]){w, h});
GLSL(vec2 coeff = fcoord * output_size/size;)
float threshold = scaler->conf.kernel.params[0];
threshold = isnan(threshold) ? 0.0 : threshold;
GLSLF("coeff = (coeff - %f) * 1.0/%f;\n", threshold, 1.0 - 2 * threshold);
GLSL(coeff = clamp(coeff, 0.0, 1.0);)
// Compute the right blend of colors
GLSL(color = texture(tex, pos + pt * (coeff - fcoord));)
GLSLF("}\n");
}
// Common constants for SMPTE ST.2084 (HDR)
static const float PQ_M1 = 2610./4096 * 1./4,
PQ_M2 = 2523./4096 * 128,
PQ_C1 = 3424./4096,
PQ_C2 = 2413./4096 * 32,
PQ_C3 = 2392./4096 * 32;
// Common constants for ARIB STD-B67 (HLG)
static const float HLG_A = 0.17883277,
HLG_B = 0.28466892,
HLG_C = 0.55991073;
// Common constants for Panasonic V-Log
static const float VLOG_B = 0.00873,
VLOG_C = 0.241514,
VLOG_D = 0.598206;
// Common constants for Sony S-Log
static const float SLOG_A = 0.432699,
SLOG_B = 0.037584,
SLOG_C = 0.616596 + 0.03,
SLOG_P = 3.538813,
SLOG_Q = 0.030001,
SLOG_K2 = 155.0 / 219.0;
// Linearize (expand), given a TRC as input. In essence, this is the ITU-R
// EOTF, calculated on an idealized (reference) monitor with a white point of
// MP_REF_WHITE and infinite contrast.
//
// These functions always output to a normalized scale of [0,1], for
// convenience of the video.c code that calls it. To get the values in an
// absolute scale, multiply the result by `mp_trc_nom_peak(trc)`
void pass_linearize(struct gl_shader_cache *sc, enum mp_csp_trc trc)
{
if (trc == MP_CSP_TRC_LINEAR)
return;
GLSLF("// linearize\n");
// Note that this clamp may technically violate the definition of
// ITU-R BT.2100, which allows for sub-blacks and super-whites to be
// displayed on the display where such would be possible. That said, the
// problem is that not all gamma curves are well-defined on the values
// outside this range, so we ignore it and just clip anyway for sanity.
GLSL(color.rgb = clamp(color.rgb, 0.0, 1.0);)
switch (trc) {
case MP_CSP_TRC_SRGB:
GLSL(color.rgb = mix(color.rgb * vec3(1.0/12.92),
pow((color.rgb + vec3(0.055))/vec3(1.055), vec3(2.4)),
lessThan(vec3(0.04045), color.rgb));)
break;
case MP_CSP_TRC_BT_1886:
GLSL(color.rgb = pow(color.rgb, vec3(2.4));)
break;
case MP_CSP_TRC_GAMMA18:
GLSL(color.rgb = pow(color.rgb, vec3(1.8));)
break;
case MP_CSP_TRC_GAMMA22:
GLSL(color.rgb = pow(color.rgb, vec3(2.2));)
break;
case MP_CSP_TRC_GAMMA28:
GLSL(color.rgb = pow(color.rgb, vec3(2.8));)
break;
case MP_CSP_TRC_PRO_PHOTO:
GLSL(color.rgb = mix(color.rgb * vec3(1.0/16.0),
pow(color.rgb, vec3(1.8)),
lessThan(vec3(0.03125), color.rgb));)
break;
case MP_CSP_TRC_PQ:
GLSLF("color.rgb = pow(color.rgb, vec3(1.0/%f));\n", PQ_M2);
GLSLF("color.rgb = max(color.rgb - vec3(%f), vec3(0.0)) \n"
" / (vec3(%f) - vec3(%f) * color.rgb);\n",
PQ_C1, PQ_C2, PQ_C3);
GLSLF("color.rgb = pow(color.rgb, vec3(1.0/%f));\n", PQ_M1);
// PQ's output range is 0-10000, but we need it to be relative to to
// MP_REF_WHITE instead, so rescale
GLSLF("color.rgb *= vec3(%f);\n", 10000 / MP_REF_WHITE);
break;
case MP_CSP_TRC_HLG:
GLSLF("color.rgb = mix(vec3(4.0) * color.rgb * color.rgb,\n"
" exp((color.rgb - vec3(%f)) * vec3(1.0/%f)) + vec3(%f),\n"
" lessThan(vec3(0.5), color.rgb));\n",
HLG_C, HLG_A, HLG_B);
break;
case MP_CSP_TRC_V_LOG:
GLSLF("color.rgb = mix((color.rgb - vec3(0.125)) * vec3(1.0/5.6), \n"
" pow(vec3(10.0), (color.rgb - vec3(%f)) * vec3(1.0/%f)) \n"
" - vec3(%f), \n"
" lessThanEqual(vec3(0.181), color.rgb)); \n",
VLOG_D, VLOG_C, VLOG_B);
break;
case MP_CSP_TRC_S_LOG1:
GLSLF("color.rgb = pow(vec3(10.0), (color.rgb - vec3(%f)) * vec3(1.0/%f))\n"
" - vec3(%f);\n",
SLOG_C, SLOG_A, SLOG_B);
break;
case MP_CSP_TRC_S_LOG2:
GLSLF("color.rgb = mix((color.rgb - vec3(%f)) * vec3(1.0/%f), \n"
" (pow(vec3(10.0), (color.rgb - vec3(%f)) * vec3(1.0/%f)) \n"
" - vec3(%f)) * vec3(1.0/%f), \n"
" lessThanEqual(vec3(%f), color.rgb)); \n",
SLOG_Q, SLOG_P, SLOG_C, SLOG_A, SLOG_B, SLOG_K2, SLOG_Q);
break;
default:
abort();
}
// Rescale to prevent clipping on non-float textures
GLSLF("color.rgb *= vec3(1.0/%f);\n", mp_trc_nom_peak(trc));
}
// Delinearize (compress), given a TRC as output. This corresponds to the
// inverse EOTF (not the OETF) in ITU-R terminology, again assuming a
// reference monitor.
//
// Like pass_linearize, this functions ingests values on an normalized scale
void pass_delinearize(struct gl_shader_cache *sc, enum mp_csp_trc trc)
{
if (trc == MP_CSP_TRC_LINEAR)
return;
GLSLF("// delinearize\n");
GLSL(color.rgb = clamp(color.rgb, 0.0, 1.0);)
GLSLF("color.rgb *= vec3(%f);\n", mp_trc_nom_peak(trc));
switch (trc) {
case MP_CSP_TRC_SRGB:
GLSL(color.rgb = mix(color.rgb * vec3(12.92),
vec3(1.055) * pow(color.rgb, vec3(1.0/2.4))
- vec3(0.055),
lessThanEqual(vec3(0.0031308), color.rgb));)
break;
case MP_CSP_TRC_BT_1886:
GLSL(color.rgb = pow(color.rgb, vec3(1.0/2.4));)
break;
case MP_CSP_TRC_GAMMA18:
GLSL(color.rgb = pow(color.rgb, vec3(1.0/1.8));)
break;
case MP_CSP_TRC_GAMMA22:
GLSL(color.rgb = pow(color.rgb, vec3(1.0/2.2));)
break;
case MP_CSP_TRC_GAMMA28:
GLSL(color.rgb = pow(color.rgb, vec3(1.0/2.8));)
break;
case MP_CSP_TRC_PRO_PHOTO:
GLSL(color.rgb = mix(color.rgb * vec3(16.0),
pow(color.rgb, vec3(1.0/1.8)),
lessThanEqual(vec3(0.001953), color.rgb));)
break;
case MP_CSP_TRC_PQ:
GLSLF("color.rgb *= vec3(1.0/%f);\n", 10000 / MP_REF_WHITE);
GLSLF("color.rgb = pow(color.rgb, vec3(%f));\n", PQ_M1);
GLSLF("color.rgb = (vec3(%f) + vec3(%f) * color.rgb) \n"
" / (vec3(1.0) + vec3(%f) * color.rgb);\n",
PQ_C1, PQ_C2, PQ_C3);
GLSLF("color.rgb = pow(color.rgb, vec3(%f));\n", PQ_M2);
break;
case MP_CSP_TRC_HLG:
GLSLF("color.rgb = mix(vec3(0.5) * sqrt(color.rgb),\n"
" vec3(%f) * log(color.rgb - vec3(%f)) + vec3(%f),\n"
" lessThan(vec3(1.0), color.rgb));\n",
HLG_A, HLG_B, HLG_C);
break;
case MP_CSP_TRC_V_LOG:
GLSLF("color.rgb = mix(vec3(5.6) * color.rgb + vec3(0.125), \n"
" vec3(%f) * log(color.rgb + vec3(%f)) \n"
" + vec3(%f), \n"
" lessThanEqual(vec3(0.01), color.rgb)); \n",
VLOG_C / M_LN10, VLOG_B, VLOG_D);
break;
case MP_CSP_TRC_S_LOG1:
GLSLF("color.rgb = vec3(%f) * log(color.rgb + vec3(%f)) + vec3(%f);\n",
SLOG_A / M_LN10, SLOG_B, SLOG_C);
break;
case MP_CSP_TRC_S_LOG2:
GLSLF("color.rgb = mix(vec3(%f) * color.rgb + vec3(%f), \n"
" vec3(%f) * log(vec3(%f) * color.rgb + vec3(%f)) \n"
" + vec3(%f), \n"
" lessThanEqual(vec3(0.0), color.rgb)); \n",
SLOG_P, SLOG_Q, SLOG_A / M_LN10, SLOG_K2, SLOG_B, SLOG_C);
break;
default:
abort();
}
}
// Apply the OOTF mapping from a given light type to display-referred light.
// Assumes absolute scale values. `peak` is used to tune the OOTF where
// applicable (currently only HLG).
static void pass_ootf(struct gl_shader_cache *sc, enum mp_csp_light light,
float peak)
{
if (light == MP_CSP_LIGHT_DISPLAY)
return;
GLSLF("// apply ootf\n");
switch (light)
{
case MP_CSP_LIGHT_SCENE_HLG: {
// HLG OOTF from BT.2100, scaled to the chosen display peak
float gamma = MPMAX(1.0, 1.2 + 0.42 * log10(peak * MP_REF_WHITE / 1000.0));
GLSLF("color.rgb *= vec3(%f * pow(dot(src_luma, color.rgb), %f));\n",
peak / pow(12, gamma), gamma - 1.0);
break;
}
case MP_CSP_LIGHT_SCENE_709_1886:
// This OOTF is defined by encoding the result as 709 and then decoding
// it as 1886; although this is called 709_1886 we actually use the
// more precise (by one decimal) values from BT.2020 instead
GLSL(color.rgb = mix(color.rgb * vec3(4.5),
vec3(1.0993) * pow(color.rgb, vec3(0.45)) - vec3(0.0993),
lessThan(vec3(0.0181), color.rgb));)
GLSL(color.rgb = pow(color.rgb, vec3(2.4));)
break;
case MP_CSP_LIGHT_SCENE_1_2:
GLSL(color.rgb = pow(color.rgb, vec3(1.2));)
break;
default:
abort();
}
}
// Inverse of the function pass_ootf, for completeness' sake.
static void pass_inverse_ootf(struct gl_shader_cache *sc, enum mp_csp_light light,
float peak)
{
if (light == MP_CSP_LIGHT_DISPLAY)
return;
GLSLF("// apply inverse ootf\n");
switch (light)
{
case MP_CSP_LIGHT_SCENE_HLG: {
float gamma = MPMAX(1.0, 1.2 + 0.42 * log10(peak * MP_REF_WHITE / 1000.0));
GLSLF("color.rgb *= vec3(1.0/%f);\n", peak / pow(12, gamma));
GLSLF("color.rgb /= vec3(max(1e-6, pow(dot(src_luma, color.rgb), %f)));\n",
(gamma - 1.0) / gamma);
break;
}
case MP_CSP_LIGHT_SCENE_709_1886:
GLSL(color.rgb = pow(color.rgb, vec3(1.0/2.4));)
GLSL(color.rgb = mix(color.rgb * vec3(1.0/4.5),
pow((color.rgb + vec3(0.0993)) * vec3(1.0/1.0993),
vec3(1/0.45)),
lessThan(vec3(0.08145), color.rgb));)
break;
case MP_CSP_LIGHT_SCENE_1_2:
GLSL(color.rgb = pow(color.rgb, vec3(1.0/1.2));)
break;
default:
abort();
}
}
// Average light level for SDR signals. This is equal to a signal level of 0.5
// under a typical presentation gamma of about 2.0.
static const float sdr_avg = 0.25;
// The threshold for which to consider an average luminance difference to be
// a sign of a scene change.
static const int scene_threshold = 0.2 * MP_REF_WHITE;
static void hdr_update_peak(struct gl_shader_cache *sc)
{
// For performance, we want to do as few atomic operations on global
// memory as possible, so use an atomic in shmem for the work group.
GLSLH(shared uint wg_sum;);
GLSL(wg_sum = 0;)
// Have each thread update the work group sum with the local value
GLSL(barrier();)
GLSLF("atomicAdd(wg_sum, uint(sig * %f));\n", MP_REF_WHITE);
// Have one thread per work group update the global atomics. We use the
// work group average even for the global sum, to make the values slightly
// more stable and smooth out tiny super-highlights.
GLSL(memoryBarrierShared();)
GLSL(barrier();)
GLSL(if (gl_LocalInvocationIndex == 0) {)
GLSL( uint wg_avg = wg_sum / (gl_WorkGroupSize.x * gl_WorkGroupSize.y);)
GLSL( atomicMax(frame_max[frame_idx], wg_avg);)
GLSL( atomicAdd(frame_avg[frame_idx], wg_avg);)
GLSL(})
const float refi = 1.0 / MP_REF_WHITE;
// Update the sig_peak/sig_avg from the old SSBO state
GLSL(uint num_wg = gl_NumWorkGroups.x * gl_NumWorkGroups.y;)
GLSL(if (frame_num > 0) {)
GLSLF(" float peak = %f * float(total_max) / float(frame_num);\n", refi);
GLSLF(" float avg = %f * float(total_avg) / float(frame_num);\n", refi);
GLSLF(" sig_peak = max(1.0, peak);\n");
GLSLF(" sig_avg = max(%f, avg);\n", sdr_avg);
GLSL(});
// Finally, to update the global state, we increment a counter per dispatch
GLSL(memoryBarrierBuffer();)
GLSL(barrier();)
GLSL(if (gl_LocalInvocationIndex == 0 && atomicAdd(counter, 1) == num_wg - 1) {)
// Since we sum up all the workgroups, we also still need to divide the
// average by the number of work groups
GLSL( counter = 0;)
GLSL( frame_avg[frame_idx] /= num_wg;)
GLSL( uint cur_max = frame_max[frame_idx];)
GLSL( uint cur_avg = frame_avg[frame_idx];)
// Scene change detection
GLSL( int diff = int(frame_num * cur_avg) - int(total_avg);)
GLSLF(" if (abs(diff) > frame_num * %d) {\n", scene_threshold);
GLSL( frame_num = 0;)
GLSL( total_max = total_avg = 0;)
GLSLF(" for (uint i = 0; i < %d; i++)\n", PEAK_DETECT_FRAMES+1);
GLSL( frame_max[i] = frame_avg[i] = 0;)
GLSL( frame_max[frame_idx] = cur_max;)
GLSL( frame_avg[frame_idx] = cur_avg;)
GLSL( })
// Add the current frame, then subtract and reset the next frame
GLSLF(" uint next = (frame_idx + 1) %% %d;\n", PEAK_DETECT_FRAMES+1);
GLSL( total_max += cur_max - frame_max[next];)
GLSL( total_avg += cur_avg - frame_avg[next];)
GLSL( frame_max[next] = frame_avg[next] = 0;)
// Update the index and count
GLSL( frame_idx = next;)
GLSLF(" frame_num = min(frame_num + 1, %d);\n", PEAK_DETECT_FRAMES);
GLSL( memoryBarrierBuffer();)
GLSL(})
}
// Tone map from a known peak brightness to the range [0,1]. If ref_peak
// is 0, we will use peak detection instead
static void pass_tone_map(struct gl_shader_cache *sc, bool detect_peak,
float src_peak, float dst_peak,
enum tone_mapping algo, float param, float desat)
{
GLSLF("// HDR tone mapping\n");
// To prevent discoloration due to out-of-bounds clipping, we need to make
// sure to reduce the value range as far as necessary to keep the entire
// signal in range, so tone map based on the brightest component.
GLSL(float sig = max(max(color.r, color.g), color.b);)
GLSLF("float sig_peak = %f;\n", src_peak);
GLSLF("float sig_avg = %f;\n", sdr_avg);
if (detect_peak)
hdr_update_peak(sc);
// Rescale the variables in order to bring it into a representation where
// 1.0 represents the dst_peak. This is because all of the tone mapping
// algorithms are defined in such a way that they map to the range [0.0, 1.0].
if (dst_peak > 1.0) {
GLSLF("sig *= %f;\n", 1.0 / dst_peak);
GLSLF("sig_peak *= %f;\n", 1.0 / dst_peak);
}
GLSL(float sig_orig = sig;)
GLSLF("float slope = min(1.0, %f / sig_avg);\n", sdr_avg);
GLSL(sig *= slope;)
GLSL(sig_peak *= slope;)
// Desaturate the color using a coefficient dependent on the signal.
// Do this after peak detection in order to prevent over-desaturating
// overly bright souces
if (desat > 0) {
float base = 0.18 * dst_peak;
GLSL(float luma = dot(dst_luma, color.rgb);)
GLSLF("float coeff = max(sig - %f, 1e-6) / max(sig, 1e-6);\n", base);
GLSLF("coeff = pow(coeff, %f);\n", 10.0 / desat);
GLSL(color.rgb = mix(color.rgb, vec3(luma), coeff);)
GLSL(sig = mix(sig, luma * slope, coeff);) // also make sure to update `sig`
}
switch (algo) {
case TONE_MAPPING_CLIP:
GLSLF("sig = %f * sig;\n", isnan(param) ? 1.0 : param);
break;
case TONE_MAPPING_MOBIUS:
GLSLF("if (sig_peak > (1.0 + 1e-6)) {\n");
GLSLF("const float j = %f;\n", isnan(param) ? 0.3 : param);
// solve for M(j) = j; M(sig_peak) = 1.0; M'(j) = 1.0
// where M(x) = scale * (x+a)/(x+b)
GLSLF("float a = -j*j * (sig_peak - 1.0) / (j*j - 2.0*j + sig_peak);\n");
GLSLF("float b = (j*j - 2.0*j*sig_peak + sig_peak) / "
"max(1e-6, sig_peak - 1.0);\n");
GLSLF("float scale = (b*b + 2.0*b*j + j*j) / (b-a);\n");
GLSL(sig = sig > j ? scale * (sig + a) / (sig + b) : sig;)
GLSLF("}\n");
break;
case TONE_MAPPING_REINHARD: {
float contrast = isnan(param) ? 0.5 : param,
offset = (1.0 - contrast) / contrast;
GLSLF("sig = sig / (sig + %f);\n", offset);
GLSLF("float scale = (sig_peak + %f) / sig_peak;\n", offset);
GLSL(sig *= scale;)
break;
}
case TONE_MAPPING_HABLE: {
float A = 0.15, B = 0.50, C = 0.10, D = 0.20, E = 0.02, F = 0.30;
GLSLHF("float hable(float x) {\n");
GLSLHF("return ((x * (%f*x + %f)+%f)/(x * (%f*x + %f) + %f)) - %f;\n",
A, C*B, D*E, A, B, D*F, E/F);
GLSLHF("}\n");
GLSL(sig = hable(sig) / hable(sig_peak);)
break;
}
case TONE_MAPPING_GAMMA: {
float gamma = isnan(param) ? 1.8 : param;
GLSLF("const float cutoff = 0.05, gamma = %f;\n", 1.0/gamma);
GLSL(float scale = pow(cutoff / sig_peak, gamma) / cutoff;)
GLSL(sig = sig > cutoff ? pow(sig / sig_peak, gamma) : scale * sig;)
break;
}
case TONE_MAPPING_LINEAR: {
float coeff = isnan(param) ? 1.0 : param;
GLSLF("sig = %f / sig_peak * sig;\n", coeff);
break;
}
default:
abort();
}
// Apply the computed scale factor to the color, linearly to prevent
// discoloration
GLSL(sig = min(sig, 1.0);)
GLSL(color.rgb *= vec3(sig / sig_orig);)
}
// Map colors from one source space to another. These source spaces must be
// known (i.e. not MP_CSP_*_AUTO), as this function won't perform any
// auto-guessing. If is_linear is true, we assume the input has already been
// linearized (e.g. for linear-scaling). If `detect_peak` is true, we will
// detect the peak instead of relying on metadata. Note that this requires
// the caller to have already bound the appropriate SSBO and set up the
// compute shader metadata
void pass_color_map(struct gl_shader_cache *sc,
struct mp_colorspace src, struct mp_colorspace dst,
enum tone_mapping algo, float tone_mapping_param,
float tone_mapping_desat, bool detect_peak,
bool gamut_warning, bool is_linear)
{
GLSLF("// color mapping\n");
// Some operations need access to the video's luma coefficients, so make
// them available
float rgb2xyz[3][3];
mp_get_rgb2xyz_matrix(mp_get_csp_primaries(src.primaries), rgb2xyz);
gl_sc_uniform_vec3(sc, "src_luma", rgb2xyz[1]);
mp_get_rgb2xyz_matrix(mp_get_csp_primaries(dst.primaries), rgb2xyz);
gl_sc_uniform_vec3(sc, "dst_luma", rgb2xyz[1]);
bool need_ootf = src.light != dst.light;
if (src.light == MP_CSP_LIGHT_SCENE_HLG && src.sig_peak != dst.sig_peak)
need_ootf = true;
// All operations from here on require linear light as a starting point,
// so we linearize even if src.gamma == dst.gamma when one of the other
// operations needs it
bool need_linear = src.gamma != dst.gamma ||
src.primaries != dst.primaries ||
src.sig_peak > dst.sig_peak ||
need_ootf;
if (need_linear && !is_linear) {
// We also pull it up so that 1.0 is the reference white
pass_linearize(sc, src.gamma);
is_linear = true;
}
// Pre-scale the incoming values into an absolute scale
GLSLF("color.rgb *= vec3(%f);\n", mp_trc_nom_peak(src.gamma));
if (need_ootf)
pass_ootf(sc, src.light, src.sig_peak);
// Adapt to the right colorspace if necessary
if (src.primaries != dst.primaries) {
struct mp_csp_primaries csp_src = mp_get_csp_primaries(src.primaries),
csp_dst = mp_get_csp_primaries(dst.primaries);
float m[3][3] = {{0}};
mp_get_cms_matrix(csp_src, csp_dst, MP_INTENT_RELATIVE_COLORIMETRIC, m);
gl_sc_uniform_mat3(sc, "cms_matrix", true, &m[0][0]);
GLSL(color.rgb = cms_matrix * color.rgb;)
}
// Tone map to prevent clipping when the source signal peak exceeds the
// encodable range or we've reduced the gamut
if (src.sig_peak > dst.sig_peak) {
pass_tone_map(sc, detect_peak, src.sig_peak, dst.sig_peak, algo,
tone_mapping_param, tone_mapping_desat);
}
if (need_ootf)
pass_inverse_ootf(sc, dst.light, dst.sig_peak);
// Post-scale the outgoing values from absolute scale to normalized.
// For SDR, we normalize to the chosen signal peak. For HDR, we normalize
// to the encoding range of the transfer function.
float dst_range = dst.sig_peak;
if (mp_trc_is_hdr(dst.gamma))
dst_range = mp_trc_nom_peak(dst.gamma);
GLSLF("color.rgb *= vec3(%f);\n", 1.0 / dst_range);
// Warn for remaining out-of-gamut colors is enabled
if (gamut_warning) {
GLSL(if (any(greaterThan(color.rgb, vec3(1.01)))))
GLSL(color.rgb = vec3(1.0) - color.rgb;) // invert
}
if (is_linear)
pass_delinearize(sc, dst.gamma);
}
// Wide usage friendly PRNG, shamelessly stolen from a GLSL tricks forum post.
// Obtain random numbers by calling rand(h), followed by h = permute(h) to
// update the state. Assumes the texture was hooked.
// permute() was modified from the original to avoid "large" numbers in
// calculations, since low-end mobile GPUs choke on them (overflow).
static void prng_init(struct gl_shader_cache *sc, AVLFG *lfg)
{
GLSLH(float mod289(float x) { return x - floor(x * 1.0/289.0) * 289.0; })
GLSLHF("float permute(float x) {\n");
GLSLH(return mod289( mod289(34.0*x + 1.0) * (fract(x) + 1.0) );)
GLSLHF("}\n");
GLSLH(float rand(float x) { return fract(x * 1.0/41.0); })
// Initialize the PRNG by hashing the position + a random uniform
GLSL(vec3 _m = vec3(HOOKED_pos, random) + vec3(1.0);)
GLSL(float h = permute(permute(permute(_m.x)+_m.y)+_m.z);)
gl_sc_uniform_dynamic(sc);
gl_sc_uniform_f(sc, "random", (double)av_lfg_get(lfg) / UINT32_MAX);
}
struct deband_opts {
int enabled;
int iterations;
float threshold;
float range;
float grain;
};
const struct deband_opts deband_opts_def = {
.iterations = 1,
.threshold = 64.0,
.range = 16.0,
.grain = 48.0,
};
#define OPT_BASE_STRUCT struct deband_opts
const struct m_sub_options deband_conf = {
.opts = (const m_option_t[]) {
OPT_INTRANGE("iterations", iterations, 0, 1, 16),
OPT_FLOATRANGE("threshold", threshold, 0, 0.0, 4096.0),
OPT_FLOATRANGE("range", range, 0, 1.0, 64.0),
OPT_FLOATRANGE("grain", grain, 0, 0.0, 4096.0),
{0}
},
.size = sizeof(struct deband_opts),
.defaults = &deband_opts_def,
};
// Stochastically sample a debanded result from a hooked texture.
void pass_sample_deband(struct gl_shader_cache *sc, struct deband_opts *opts,
AVLFG *lfg, enum mp_csp_trc trc)
{
// Initialize the PRNG
GLSLF("{\n");
prng_init(sc, lfg);
// Helper: Compute a stochastic approximation of the avg color around a
// pixel
GLSLHF("vec4 average(float range, inout float h) {\n");
// Compute a random rangle and distance
GLSLH(float dist = rand(h) * range; h = permute(h);)
GLSLH(float dir = rand(h) * 6.2831853; h = permute(h);)
GLSLH(vec2 o = dist * vec2(cos(dir), sin(dir));)
// Sample at quarter-turn intervals around the source pixel
GLSLH(vec4 ref[4];)
GLSLH(ref[0] = HOOKED_texOff(vec2( o.x, o.y));)
GLSLH(ref[1] = HOOKED_texOff(vec2(-o.y, o.x));)
GLSLH(ref[2] = HOOKED_texOff(vec2(-o.x, -o.y));)
GLSLH(ref[3] = HOOKED_texOff(vec2( o.y, -o.x));)
// Return the (normalized) average
GLSLH(return (ref[0] + ref[1] + ref[2] + ref[3])*0.25;)
GLSLHF("}\n");
// Sample the source pixel
GLSL(color = HOOKED_tex(HOOKED_pos);)
GLSLF("vec4 avg, diff;\n");
for (int i = 1; i <= opts->iterations; i++) {
// Sample the average pixel and use it instead of the original if
// the difference is below the given threshold
GLSLF("avg = average(%f, h);\n", i * opts->range);
GLSL(diff = abs(color - avg);)
GLSLF("color = mix(avg, color, greaterThan(diff, vec4(%f)));\n",
opts->threshold / (i * 16384.0));
}
// Add some random noise to smooth out residual differences
GLSL(vec3 noise;)
GLSL(noise.x = rand(h); h = permute(h);)
GLSL(noise.y = rand(h); h = permute(h);)
GLSL(noise.z = rand(h); h = permute(h);)
// Noise is scaled to the signal level to prevent extreme noise for HDR
float gain = opts->grain/8192.0 / mp_trc_nom_peak(trc);
GLSLF("color.xyz += %f * (noise - vec3(0.5));\n", gain);
GLSLF("}\n");
}
// Assumes the texture was hooked
void pass_sample_unsharp(struct gl_shader_cache *sc, float param) {
GLSLF("{\n");
GLSL(float st1 = 1.2;)
GLSL(vec4 p = HOOKED_tex(HOOKED_pos);)
GLSL(vec4 sum1 = HOOKED_texOff(st1 * vec2(+1, +1))
+ HOOKED_texOff(st1 * vec2(+1, -1))
+ HOOKED_texOff(st1 * vec2(-1, +1))
+ HOOKED_texOff(st1 * vec2(-1, -1));)
GLSL(float st2 = 1.5;)
GLSL(vec4 sum2 = HOOKED_texOff(st2 * vec2(+1, 0))
+ HOOKED_texOff(st2 * vec2( 0, +1))
+ HOOKED_texOff(st2 * vec2(-1, 0))
+ HOOKED_texOff(st2 * vec2( 0, -1));)
GLSL(vec4 t = p * 0.859375 + sum2 * -0.1171875 + sum1 * -0.09765625;)
GLSLF("color = p + t * %f;\n", param);
GLSLF("}\n");
}
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