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mutter/clutter/clutter/clutter-color-state.c
Joan Torres 3b53f7cb6c clutter/color-state: Drop using default colorspace and default tf 
Use the defaults explicitliy, which is SRGB for both.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/4020>
2024-10-01 10:55:02 +00:00

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/*
* Clutter.
*
* An OpenGL based 'interactive canvas' library.
*
* Copyright (C) 2022 Intel Corporation.
* Copyright (C) 2023-2024 Red Hat
*
* This library 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 of the License, or (at your option) any later version.
*
* This library 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 this library. If not, see <http://www.gnu.org/licenses/>.
*
* Author:
* Naveen Kumar <naveen1.kumar@intel.com>
* Jonas Ådahl <jadahl@redhat.com>
*/
/**
* ClutterColorState:
*
* Color state of each ClutterActor
*
* The #ClutterColorState class contains the colorspace of each color
* states (e.g. sRGB colorspace).
*
* Each [class@Actor] would own such an object.
*
* A single #ClutterColorState object can be shared by multiple [class@Actor]
* or maybe a separate color state for each [class@Actor] (depending on whether
* #ClutterColorState would be statefull or stateless).
*
* #ClutterColorState, if not set during construction, it will default to sRGB
* color state
*
* The #ClutterColorState would have API to get the colorspace, whether the
* actor content is in pq or not, and things like that
*/
#include "config.h"
#include "clutter/clutter-color-state-private.h"
#include "clutter/clutter-color-manager-private.h"
#include "clutter/clutter-debug.h"
#include "clutter/clutter-enum-types.h"
#include "clutter/clutter-private.h"
#define UNIFORM_NAME_LUMINANCE_MAPPING "luminance_mapping"
#define UNIFORM_NAME_COLOR_SPACE_MAPPING "color_space_mapping"
struct _ClutterColorState
{
GObject parent_instance;
};
typedef struct _ClutterColorStatePrivate
{
ClutterContext *context;
unsigned int id;
ClutterColorimetry colorimetry;
ClutterEOTF eotf;
ClutterLuminance luminance;
} ClutterColorStatePrivate;
G_DEFINE_TYPE_WITH_PRIVATE (ClutterColorState,
clutter_color_state,
G_TYPE_OBJECT)
guint
clutter_color_transform_key_hash (gconstpointer data)
{
const ClutterColorTransformKey *key = data;
return (key->source.transfer_function ^
key->target.transfer_function);
}
gboolean
clutter_color_transform_key_equal (gconstpointer data1,
gconstpointer data2)
{
const ClutterColorTransformKey *key1 = data1;
const ClutterColorTransformKey *key2 = data2;
return (key1->source.transfer_function == key2->source.transfer_function &&
key1->target.transfer_function == key2->target.transfer_function);
}
void
clutter_color_transform_key_init (ClutterColorTransformKey *key,
ClutterColorState *color_state,
ClutterColorState *target_color_state)
{
ClutterColorStatePrivate *priv =
clutter_color_state_get_instance_private (color_state);
ClutterColorStatePrivate *target_priv =
clutter_color_state_get_instance_private (target_color_state);
key->source.transfer_function = priv->eotf.tf_name;
key->target.transfer_function = target_priv->eotf.tf_name;
}
static const char *
clutter_colorspace_to_string (ClutterColorspace colorspace)
{
switch (colorspace)
{
case CLUTTER_COLORSPACE_SRGB:
return "sRGB";
case CLUTTER_COLORSPACE_BT2020:
return "BT.2020";
}
g_assert_not_reached ();
}
static const char *
clutter_eotf_to_string (ClutterEOTF eotf)
{
switch (eotf.tf_name)
{
case CLUTTER_TRANSFER_FUNCTION_SRGB:
return "sRGB";
case CLUTTER_TRANSFER_FUNCTION_PQ:
return "PQ";
case CLUTTER_TRANSFER_FUNCTION_LINEAR:
return "linear";
}
g_assert_not_reached ();
}
unsigned int
clutter_color_state_get_id (ClutterColorState *color_state)
{
ClutterColorStatePrivate *priv;
g_return_val_if_fail (CLUTTER_IS_COLOR_STATE (color_state), 0);
priv = clutter_color_state_get_instance_private (color_state);
return priv->id;
}
const ClutterColorimetry *
clutter_color_state_get_colorimetry (ClutterColorState *color_state)
{
ClutterColorStatePrivate *priv;
g_return_val_if_fail (CLUTTER_IS_COLOR_STATE (color_state), NULL);
priv = clutter_color_state_get_instance_private (color_state);
return &priv->colorimetry;
}
const ClutterEOTF *
clutter_color_state_get_eotf (ClutterColorState *color_state)
{
ClutterColorStatePrivate *priv;
g_return_val_if_fail (CLUTTER_IS_COLOR_STATE (color_state), NULL);
priv = clutter_color_state_get_instance_private (color_state);
return &priv->eotf;
}
static const ClutterLuminance sdr_default_luminance = {
.type = CLUTTER_LUMINANCE_TYPE_DERIVED,
.min = 0.2f,
.max = 80.0f,
.ref = 80.0f,
};
static const ClutterLuminance pq_default_luminance = {
.type = CLUTTER_LUMINANCE_TYPE_DERIVED,
.min = 0.005f,
.max = 10000.0f,
.ref = 203.0f,
};
const ClutterLuminance *
clutter_eotf_get_default_luminance (ClutterEOTF eotf)
{
switch (eotf.tf_name)
{
case CLUTTER_TRANSFER_FUNCTION_SRGB:
case CLUTTER_TRANSFER_FUNCTION_LINEAR:
return &sdr_default_luminance;
case CLUTTER_TRANSFER_FUNCTION_PQ:
return &pq_default_luminance;
}
g_assert_not_reached ();
}
const ClutterLuminance *
clutter_color_state_get_luminance (ClutterColorState *color_state)
{
ClutterColorStatePrivate *priv;
g_return_val_if_fail (CLUTTER_IS_COLOR_STATE (color_state), NULL);
priv = clutter_color_state_get_instance_private (color_state);
switch (priv->luminance.type)
{
case CLUTTER_LUMINANCE_TYPE_DERIVED:
return clutter_eotf_get_default_luminance (priv->eotf);
case CLUTTER_LUMINANCE_TYPE_EXPLICIT:
return &priv->luminance;
}
}
void
clutter_primaries_ensure_normalized_range (ClutterPrimaries *primaries)
{
if (!primaries)
return;
primaries->r_x = CLAMP (primaries->r_x, 0.0f, 1.0f);
primaries->r_y = CLAMP (primaries->r_y, 0.0f, 1.0f);
primaries->g_x = CLAMP (primaries->g_x, 0.0f, 1.0f);
primaries->g_y = CLAMP (primaries->g_y, 0.0f, 1.0f);
primaries->b_x = CLAMP (primaries->b_x, 0.0f, 1.0f);
primaries->b_y = CLAMP (primaries->b_y, 0.0f, 1.0f);
primaries->w_x = CLAMP (primaries->w_x, 0.0f, 1.0f);
primaries->w_y = CLAMP (primaries->w_y, 0.0f, 1.0f);
}
static void
clutter_color_state_finalize (GObject *object)
{
ClutterColorState *color_state = CLUTTER_COLOR_STATE (object);
ClutterColorStatePrivate *priv =
clutter_color_state_get_instance_private (color_state);
if (priv->colorimetry.type == CLUTTER_COLORIMETRY_TYPE_PRIMARIES)
g_clear_pointer (&priv->colorimetry.primaries, g_free);
G_OBJECT_CLASS (clutter_color_state_parent_class)->finalize (object);
}
static void
clutter_color_state_class_init (ClutterColorStateClass *klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
gobject_class->finalize = clutter_color_state_finalize;
}
static void
clutter_color_state_init (ClutterColorState *color_state)
{
}
/**
* clutter_color_state_new:
*
* Create a new ClutterColorState object.
*
* Return value: A new ClutterColorState object.
**/
ClutterColorState *
clutter_color_state_new (ClutterContext *context,
ClutterColorspace colorspace,
ClutterTransferFunction transfer_function)
{
return clutter_color_state_new_full (context,
colorspace, transfer_function, NULL,
-1.0f, -1.0f, -1.0f);
}
/**
* clutter_color_state_new_full:
*
* Create a new ClutterColorState object with all possible parameters. Some
* arguments might not be valid to set with other arguments.
*
* Return value: A new ClutterColorState object.
**/
ClutterColorState *
clutter_color_state_new_full (ClutterContext *context,
ClutterColorspace colorspace,
ClutterTransferFunction transfer_function,
ClutterPrimaries *primaries,
float min_lum,
float max_lum,
float ref_lum)
{
ClutterColorState *color_state;
ClutterColorStatePrivate *priv;
ClutterColorManager *color_manager;
color_state = g_object_new (CLUTTER_TYPE_COLOR_STATE, NULL);
priv = clutter_color_state_get_instance_private (color_state);
color_manager = clutter_context_get_color_manager (context);
priv->context = context;
priv->id = clutter_color_manager_get_next_id (color_manager);
if (primaries)
{
priv->colorimetry.type = CLUTTER_COLORIMETRY_TYPE_PRIMARIES;
priv->colorimetry.primaries = g_memdup2 (primaries, sizeof (*primaries));
}
else
{
priv->colorimetry.type = CLUTTER_COLORIMETRY_TYPE_COLORSPACE;
priv->colorimetry.colorspace = colorspace;
}
priv->eotf.type = CLUTTER_EOTF_TYPE_NAMED;
priv->eotf.tf_name = transfer_function;
if (min_lum >= 0.0f && max_lum > 0.0f && ref_lum >= 0.0f)
{
priv->luminance.type = CLUTTER_LUMINANCE_TYPE_EXPLICIT;
priv->luminance.min = min_lum;
priv->luminance.max = max_lum;
priv->luminance.ref = ref_lum;
}
else
{
priv->luminance.type = CLUTTER_LUMINANCE_TYPE_DERIVED;
}
return color_state;
}
static const char pq_eotf_source[] =
"// pq_eotf:\n"
"// @color: Normalized ([0,1]) electrical signal value\n"
"// Returns: tristimulus values ([0,1])\n"
"vec3 pq_eotf (vec3 color)\n"
"{\n"
" const float c1 = 0.8359375;\n"
" const float c2 = 18.8515625;\n"
" const float c3 = 18.6875;\n"
"\n"
" const float oo_m1 = 1.0 / 0.1593017578125;\n"
" const float oo_m2 = 1.0 / 78.84375;\n"
"\n"
" vec3 num = max (pow (color, vec3 (oo_m2)) - c1, vec3 (0.0));\n"
" vec3 den = c2 - c3 * pow (color, vec3 (oo_m2));\n"
"\n"
" return pow (num / den, vec3 (oo_m1));\n"
"}\n"
"\n"
"vec4 pq_eotf (vec4 color)\n"
"{\n"
" return vec4 (pq_eotf (color.rgb), color.a);\n"
"}\n";
static const char pq_inv_eotf_source[] =
"// pq_inv_eotf:\n"
"// @color: Normalized tristimulus values ([0,1])"
"// Returns: Normalized ([0,1]) electrical signal value\n"
"vec3 pq_inv_eotf (vec3 color)\n"
"{\n"
" float m1 = 0.1593017578125;\n"
" float m2 = 78.84375;\n"
" float c1 = 0.8359375;\n"
" float c2 = 18.8515625;\n"
" float c3 = 18.6875;\n"
" vec3 color_pow_m1 = pow (color, vec3 (m1));\n"
" vec3 num = vec3 (c1) + c2 * color_pow_m1;\n"
" vec3 denum = vec3 (1.0) + c3 * color_pow_m1;\n"
" return pow (num / denum, vec3 (m2));\n"
"}\n"
"\n"
"vec4 pq_inv_eotf (vec4 color)\n"
"{\n"
" return vec4 (pq_inv_eotf (color.rgb), color.a);\n"
"}\n";
static const char srgb_eotf_source[] =
"// srgb_eotf:\n"
"// @color: Normalized ([0,1]) electrical signal value.\n"
"// Returns: Normalized tristimulus values ([0,1])\n"
"vec3 srgb_eotf (vec3 color)\n"
"{\n"
" bvec3 is_low = lessThanEqual (color, vec3 (0.04045));\n"
" vec3 lo_part = color / 12.92;\n"
" vec3 hi_part = pow ((color + 0.055) / 1.055, vec3 (12.0 / 5.0));\n"
" return mix (hi_part, lo_part, is_low);\n"
"}\n"
"\n"
"vec4 srgb_eotf (vec4 color)\n"
"{\n"
" return vec4 (srgb_eotf (color.rgb), color.a);\n"
"}\n";
static const char srgb_inv_eotf_source[] =
"// srgb_inv_eotf:\n"
"// @color: Normalized ([0,1]) tristimulus values\n"
"// Returns: Normalized ([0,1]) electrical signal value\n"
"vec3 srgb_inv_eotf (vec3 color)\n"
"{\n"
" bvec3 is_lo = lessThanEqual (color, vec3 (0.0031308));\n"
"\n"
" vec3 lo_part = color * 12.92;\n"
" vec3 hi_part = pow (color, vec3 (5.0 / 12.0)) * 1.055 - 0.055;\n"
" return mix (hi_part, lo_part, is_lo);\n"
"}\n"
"\n"
"vec4 srgb_inv_eotf (vec4 color)\n"
"{\n"
" return vec4 (srgb_inv_eotf (color.rgb), color.a);\n"
"}\n";
typedef struct _TransferFunction
{
const char *source;
const char *name;
} TransferFunction;
static const TransferFunction pq_eotf = {
.source = pq_eotf_source,
.name = "pq_eotf",
};
static const TransferFunction pq_inv_eotf = {
.source = pq_inv_eotf_source,
.name = "pq_inv_eotf",
};
static const TransferFunction srgb_eotf = {
.source = srgb_eotf_source,
.name = "srgb_eotf",
};
static const TransferFunction srgb_inv_eotf = {
.source = srgb_inv_eotf_source,
.name = "srgb_inv_eotf",
};
static void
append_shader_description (GString *snippet_source,
ClutterColorState *color_state,
ClutterColorState *target_color_state)
{
ClutterColorStatePrivate *priv =
clutter_color_state_get_instance_private (color_state);
ClutterColorStatePrivate *target_priv =
clutter_color_state_get_instance_private (target_color_state);
g_string_append_printf (snippet_source,
" // %s to %s\n",
clutter_eotf_to_string (priv->eotf),
clutter_eotf_to_string (target_priv->eotf));
}
static const TransferFunction *
get_eotf (ClutterColorState *color_state)
{
ClutterColorStatePrivate *priv =
clutter_color_state_get_instance_private (color_state);
switch (priv->eotf.tf_name)
{
case CLUTTER_TRANSFER_FUNCTION_PQ:
return &pq_eotf;
case CLUTTER_TRANSFER_FUNCTION_SRGB:
return &srgb_eotf;
case CLUTTER_TRANSFER_FUNCTION_LINEAR:
return NULL;
}
g_warning ("Unhandled tranfer function %s",
clutter_eotf_to_string (priv->eotf));
return NULL;
}
static const TransferFunction *
get_inv_eotf (ClutterColorState *color_state)
{
ClutterColorStatePrivate *priv =
clutter_color_state_get_instance_private (color_state);
switch (priv->eotf.tf_name)
{
case CLUTTER_TRANSFER_FUNCTION_PQ:
return &pq_inv_eotf;
case CLUTTER_TRANSFER_FUNCTION_SRGB:
return &srgb_inv_eotf;
case CLUTTER_TRANSFER_FUNCTION_LINEAR:
return NULL;
}
g_warning ("Unhandled tranfer function %s",
clutter_eotf_to_string (priv->eotf));
return NULL;
}
static void
get_transfer_functions (ClutterColorState *color_state,
ClutterColorState *target_color_state,
const TransferFunction **pre_transfer_function,
const TransferFunction **post_transfer_function)
{
if (clutter_color_state_equals (color_state, target_color_state))
return;
*pre_transfer_function = get_eotf (color_state);
*post_transfer_function = get_inv_eotf (target_color_state);
}
/* Primaries and white point retrieved from:
* https://www.color.org */
static const ClutterPrimaries srgb_primaries = {
.r_x = 0.64f, .r_y = 0.33f,
.g_x = 0.30f, .g_y = 0.60f,
.b_x = 0.15f, .b_y = 0.06f,
.w_x = 0.3127f, .w_y = 0.3290f,
};
static const ClutterPrimaries bt2020_primaries = {
.r_x = 0.708f, .r_y = 0.292f,
.g_x = 0.170f, .g_y = 0.797f,
.b_x = 0.131f, .b_y = 0.046f,
.w_x = 0.3127f, .w_y = 0.3290f,
};
static const ClutterPrimaries *
get_primaries (ClutterColorState *color_state)
{
ClutterColorStatePrivate *priv;
priv = clutter_color_state_get_instance_private (color_state);
switch (priv->colorimetry.type)
{
case CLUTTER_COLORIMETRY_TYPE_PRIMARIES:
return priv->colorimetry.primaries;
case CLUTTER_COLORIMETRY_TYPE_COLORSPACE:
switch (priv->colorimetry.colorspace)
{
case CLUTTER_COLORSPACE_SRGB:
return &srgb_primaries;
case CLUTTER_COLORSPACE_BT2020:
return &bt2020_primaries;
}
g_warning ("Unhandled colorspace %s",
clutter_colorspace_to_string (priv->colorimetry.colorspace));
}
return &srgb_primaries;
}
static gboolean
chromaticity_equal (float x1,
float y1,
float x2,
float y2)
{
return G_APPROX_VALUE (x1, x2, 0.000001f) &&
G_APPROX_VALUE (y1, y2, 0.000001f);
}
static gboolean
primaries_white_point_equal (ClutterColorState *color_state,
ClutterColorState *other_color_state)
{
const ClutterPrimaries *primaries;
const ClutterPrimaries *other_primaries;
primaries = get_primaries (color_state);
other_primaries = get_primaries (other_color_state);
return chromaticity_equal (primaries->w_x, primaries->w_y,
other_primaries->w_x, other_primaries->w_y);
}
static void
get_white_chromaticity_in_XYZ (float x,
float y,
graphene_vec3_t *chromaticity_XYZ)
{
if (y == 0.0f)
{
/* Avoid a division by 0 */
y = FLT_EPSILON;
g_warning ("White point y coordinate is 0, something is probably wrong");
}
graphene_vec3_init (chromaticity_XYZ,
x / y,
1,
(1 - x - y) / y);
}
/*
* Get the matrix rgb_to_xyz that makes:
*
* color_XYZ = rgb_to_xyz * color_RGB
*
* Steps:
*
* (1) white_point_XYZ = rgb_to_xyz * white_point_RGB
*
* Breaking down rgb_to_xyz: rgb_to_xyz = primaries_mat * coefficients_mat
*
* (2) white_point_XYZ = primaries_mat * coefficients_mat * white_point_RGB
*
* white_point_RGB is (1, 1, 1) and coefficients_mat is a diagonal matrix:
* coefficients_vec = coefficients_mat * white_point_RGB
*
* (3) white_point_XYZ = primaries_mat * coefficients_vec
*
* (4) primaries_mat^-1 * white_point_XYZ = coefficients_vec
*
* When coefficients_vec is calculated, coefficients_mat can be composed to
* finally solve:
*
* (5) rgb_to_xyz = primaries_mat * coefficients_mat
*
* Notes:
*
* white_point_XYZ: xy white point coordinates transformed to XYZ space
* using the maximum luminance: Y = 1
*
* primaries_mat: matrix made from xy chromaticities transformed to xyz
* considering x + y + z = 1
*
* xyz_to_rgb = rgb_to_xyz^-1
*
* Reference:
* https://www.ryanjuckett.com/rgb-color-space-conversion/
*/
static gboolean
get_color_space_trans_matrices (ClutterColorState *color_state,
graphene_matrix_t *rgb_to_xyz,
graphene_matrix_t *xyz_to_rgb)
{
const ClutterPrimaries *primaries = get_primaries (color_state);
graphene_matrix_t coefficients_mat;
graphene_matrix_t inv_primaries_mat;
graphene_matrix_t primaries_mat;
graphene_vec3_t white_point_XYZ;
graphene_vec3_t coefficients;
graphene_matrix_init_from_float (
&primaries_mat,
(float [16]) {
primaries->r_x, primaries->r_y, 1 - primaries->r_x - primaries->r_y, 0,
primaries->g_x, primaries->g_y, 1 - primaries->g_x - primaries->g_y, 0,
primaries->b_x, primaries->b_y, 1 - primaries->b_x - primaries->b_y, 0,
0, 0, 0, 1,
});
if (!graphene_matrix_inverse (&primaries_mat, &inv_primaries_mat))
return FALSE;
get_white_chromaticity_in_XYZ (primaries->w_x, primaries->w_y, &white_point_XYZ);
graphene_matrix_transform_vec3 (&inv_primaries_mat, &white_point_XYZ, &coefficients);
graphene_matrix_init_from_float (
&coefficients_mat,
(float [16]) {
graphene_vec3_get_x (&coefficients), 0, 0, 0,
0, graphene_vec3_get_y (&coefficients), 0, 0,
0, 0, graphene_vec3_get_z (&coefficients), 0,
0, 0, 0, 1,
});
graphene_matrix_multiply (&coefficients_mat, &primaries_mat, rgb_to_xyz);
if (!graphene_matrix_inverse (rgb_to_xyz, xyz_to_rgb))
return FALSE;
return TRUE;
}
/*
* Get the matrix that converts XYZ chromaticity relative to src_white_point
* to XYZ chromaticity relative to dst_white_point:
*
* dst_XYZ = chromatic_adaptation * src_XYZ
*
* Steps:
*
* chromatic_adaptation = bradford_mat^-1 * coefficients_mat * bradford_mat
*
* coefficients_mat = diag (coefficients)
*
* coefficients = dst_white_LMS / src_white_LMS
*
* dst_white_LMS = bradford_mat * dst_white_XYZ
* src_white_LMS = bradford_mat * src_white_XYZ
*
* Notes:
*
* *_white_XYZ: xy white point coordinates transformed to XYZ space
* using the maximum luminance: Y = 1
*
* Bradford matrix and reference:
* http://www.brucelindbloom.com/index.html?Eqn_ChromAdapt.html
*/
static void
get_chromatic_adaptation (ClutterColorState *color_state,
ClutterColorState *target_color_state,
graphene_matrix_t *chromatic_adaptation)
{
const ClutterPrimaries *source_primaries = get_primaries (color_state);
const ClutterPrimaries *target_primaries = get_primaries (target_color_state);
graphene_matrix_t coefficients_mat;
graphene_matrix_t bradford_mat, inv_bradford_mat;
graphene_vec3_t src_white_point_XYZ, dst_white_point_XYZ;
graphene_vec3_t src_white_point_LMS, dst_white_point_LMS;
graphene_vec3_t coefficients;
graphene_matrix_init_from_float (
&bradford_mat,
(float [16]) {
0.8951f, -0.7502f, 0.0389f, 0,
0.2664f, 1.7135f, -0.0685f, 0,
-0.1614f, 0.0367f, 1.0296f, 0,
0, 0, 0, 1,
});
graphene_matrix_init_from_float (
&inv_bradford_mat,
(float [16]) {
0.9869929f, 0.4323053f, -0.0085287f, 0,
-0.1470543f, 0.5183603f, 0.0400428f, 0,
0.1599627f, 0.0492912f, 0.9684867f, 0,
0, 0, 0, 1,
});
get_white_chromaticity_in_XYZ (source_primaries->w_x, source_primaries->w_y,
&src_white_point_XYZ);
get_white_chromaticity_in_XYZ (target_primaries->w_x, target_primaries->w_y,
&dst_white_point_XYZ);
graphene_matrix_transform_vec3 (&bradford_mat, &src_white_point_XYZ,
&src_white_point_LMS);
graphene_matrix_transform_vec3 (&bradford_mat, &dst_white_point_XYZ,
&dst_white_point_LMS);
graphene_vec3_divide (&dst_white_point_LMS, &src_white_point_LMS,
&coefficients);
graphene_matrix_init_from_float (
&coefficients_mat,
(float [16]) {
graphene_vec3_get_x (&coefficients), 0, 0, 0,
0, graphene_vec3_get_y (&coefficients), 0, 0,
0, 0, graphene_vec3_get_z (&coefficients), 0,
0, 0, 0, 1,
});
graphene_matrix_multiply (&bradford_mat, &coefficients_mat,
chromatic_adaptation);
graphene_matrix_multiply (chromatic_adaptation, &inv_bradford_mat,
chromatic_adaptation);
}
static void
get_color_space_mapping_matrix (ClutterColorState *color_state,
ClutterColorState *target_color_state,
float out_color_space_mapping[9])
{
graphene_matrix_t matrix;
graphene_matrix_t src_rgb_to_xyz, src_xyz_to_rgb;
graphene_matrix_t target_rgb_to_xyz, target_xyz_to_rgb;
graphene_matrix_t chromatic_adaptation;
if (!get_color_space_trans_matrices (color_state,
&src_rgb_to_xyz,
&src_xyz_to_rgb) ||
!get_color_space_trans_matrices (target_color_state,
&target_rgb_to_xyz,
&target_xyz_to_rgb))
{
graphene_matrix_init_identity (&matrix);
}
else
{
if (!primaries_white_point_equal (color_state, target_color_state))
{
get_chromatic_adaptation (color_state, target_color_state,
&chromatic_adaptation);
graphene_matrix_multiply (&src_rgb_to_xyz, &chromatic_adaptation,
&matrix);
graphene_matrix_multiply (&matrix, &target_xyz_to_rgb,
&matrix);
}
else
{
graphene_matrix_multiply (&src_rgb_to_xyz, &target_xyz_to_rgb, &matrix);
}
}
out_color_space_mapping[0] = graphene_matrix_get_value (&matrix, 0, 0);
out_color_space_mapping[1] = graphene_matrix_get_value (&matrix, 0, 1);
out_color_space_mapping[2] = graphene_matrix_get_value (&matrix, 0, 2);
out_color_space_mapping[3] = graphene_matrix_get_value (&matrix, 1, 0);
out_color_space_mapping[4] = graphene_matrix_get_value (&matrix, 1, 1);
out_color_space_mapping[5] = graphene_matrix_get_value (&matrix, 1, 2);
out_color_space_mapping[6] = graphene_matrix_get_value (&matrix, 2, 0);
out_color_space_mapping[7] = graphene_matrix_get_value (&matrix, 2, 1);
out_color_space_mapping[8] = graphene_matrix_get_value (&matrix, 2, 2);
}
static CoglSnippet *
clutter_color_state_get_transform_snippet (ClutterColorState *color_state,
ClutterColorState *target_color_state)
{
ClutterColorStatePrivate *priv;
ClutterColorManager *color_manager;
ClutterColorTransformKey transform_key;
CoglSnippet *snippet;
const TransferFunction *pre_transfer_function = NULL;
const TransferFunction *post_transfer_function = NULL;
g_autoptr (GString) globals_source = NULL;
g_autoptr (GString) snippet_source = NULL;
priv = clutter_color_state_get_instance_private (color_state);
color_manager = clutter_context_get_color_manager (priv->context);
clutter_color_transform_key_init (&transform_key,
color_state,
target_color_state);
snippet = clutter_color_manager_lookup_snippet (color_manager,
&transform_key);
if (snippet)
return g_object_ref (snippet);
get_transfer_functions (color_state, target_color_state,
&pre_transfer_function,
&post_transfer_function);
globals_source = g_string_new (NULL);
if (pre_transfer_function)
g_string_append_printf (globals_source, "%s\n", pre_transfer_function->source);
if (post_transfer_function)
g_string_append_printf (globals_source, "%s\n", post_transfer_function->source);
g_string_append (globals_source,
"uniform float " UNIFORM_NAME_LUMINANCE_MAPPING ";\n");
g_string_append (globals_source,
"uniform mat3 " UNIFORM_NAME_COLOR_SPACE_MAPPING ";\n");
/*
* The following statements generate a shader snippet that transforms colors
* from one color state (transfer function, color space, color encoding) into
* another. When the target color state is optically encoded, we always draw
* into an intermediate 64 bit half float typed pixel.
*
* The value stored in this pixel is roughly the luminance expected by the
* target color state's transfer function.
*
* For sRGB that means luminance relative the reference display as defined by
* the sRGB specification, i.e. a value typically between 0.0 and 1.0. For PQ
* this means absolute luminance in cd/m² (nits).
*
* The snippet contains a pipeline that roughly looks like this:
*
* color = pre_transfer_function (color)
* color *= luminance_gain
* color = color_space_mapping_matrix * color
* color = post_transfer_function (color)
*
*/
snippet_source = g_string_new (NULL);
append_shader_description (snippet_source, color_state, target_color_state);
g_string_append (snippet_source,
" vec3 color_state_color = cogl_color_out.rgb;\n");
if (pre_transfer_function)
{
g_string_append_printf (snippet_source,
" color_state_color = %s (color_state_color);\n",
pre_transfer_function->name);
}
g_string_append (snippet_source,
" color_state_color = "
UNIFORM_NAME_LUMINANCE_MAPPING " * color_state_color;\n");
g_string_append (snippet_source,
" color_state_color = "
UNIFORM_NAME_COLOR_SPACE_MAPPING " * color_state_color;\n");
if (post_transfer_function)
{
g_string_append_printf (snippet_source,
" // Post transfer function\n"
" color_state_color = %s (color_state_color);\n",
post_transfer_function->name);
}
g_string_append (snippet_source,
" cogl_color_out = vec4 (color_state_color, cogl_color_out.a);\n");
snippet = cogl_snippet_new (COGL_SNIPPET_HOOK_FRAGMENT,
globals_source->str,
snippet_source->str);
cogl_snippet_set_capability (snippet,
CLUTTER_PIPELINE_CAPABILITY,
CLUTTER_PIPELINE_CAPABILITY_COLOR_STATE);
clutter_color_manager_add_snippet (color_manager,
&transform_key,
g_object_ref (snippet));
return snippet;
}
static float
get_luminance_mapping (ClutterColorState *color_state,
ClutterColorState *target_color_state)
{
const ClutterLuminance *lum;
const ClutterLuminance *target_lum;
lum = clutter_color_state_get_luminance (color_state);
target_lum = clutter_color_state_get_luminance (target_color_state);
/* this is a very basic, non-contrast preserving way of matching the reference
* luminance level */
return (target_lum->ref / lum->ref) * (lum->max / target_lum->max);
}
void
clutter_color_state_update_uniforms (ClutterColorState *color_state,
ClutterColorState *target_color_state,
CoglPipeline *pipeline)
{
float luminance_mapping;
float color_space_mapping[9] = { 0 };
int uniform_location_luminance_mapping;
int uniform_location_color_space_mapping;
luminance_mapping = get_luminance_mapping (color_state, target_color_state);
uniform_location_luminance_mapping =
cogl_pipeline_get_uniform_location (pipeline,
UNIFORM_NAME_LUMINANCE_MAPPING);
cogl_pipeline_set_uniform_1f (pipeline,
uniform_location_luminance_mapping,
luminance_mapping);
get_color_space_mapping_matrix (color_state, target_color_state,
color_space_mapping);
uniform_location_color_space_mapping =
cogl_pipeline_get_uniform_location (pipeline,
UNIFORM_NAME_COLOR_SPACE_MAPPING);
cogl_pipeline_set_uniform_matrix (pipeline,
uniform_location_color_space_mapping,
3,
1,
FALSE,
color_space_mapping);
}
void
clutter_color_state_add_pipeline_transform (ClutterColorState *color_state,
ClutterColorState *target_color_state,
CoglPipeline *pipeline)
{
g_autoptr (CoglSnippet) snippet = NULL;
g_return_if_fail (CLUTTER_IS_COLOR_STATE (color_state));
g_return_if_fail (CLUTTER_IS_COLOR_STATE (target_color_state));
snippet = clutter_color_state_get_transform_snippet (color_state,
target_color_state);
cogl_pipeline_add_snippet (pipeline, snippet);
clutter_color_state_update_uniforms (color_state,
target_color_state,
pipeline);
}
static gboolean
luminance_value_approx_equal (float lum,
float other_lum,
float epsilon)
{
if (lum == 0.0f || other_lum == 0.0f)
return lum == other_lum;
return G_APPROX_VALUE (lum / other_lum, 1.0f, epsilon);
}
static gboolean
luminances_equal (ClutterColorState *color_state,
ClutterColorState *other_color_state)
{
const ClutterLuminance *lum;
const ClutterLuminance *other_lum;
lum = clutter_color_state_get_luminance (color_state);
other_lum = clutter_color_state_get_luminance (other_color_state);
return luminance_value_approx_equal (lum->min, other_lum->min, 0.1f) &&
luminance_value_approx_equal (lum->max, other_lum->max, 0.1f) &&
luminance_value_approx_equal (lum->ref, other_lum->ref, 0.1f);
}
static gboolean
colorimetry_equal (ClutterColorState *color_state,
ClutterColorState *other_color_state)
{
ClutterColorStatePrivate *priv;
ClutterColorStatePrivate *other_priv;
const ClutterPrimaries *primaries;
const ClutterPrimaries *other_primaries;
priv = clutter_color_state_get_instance_private (color_state);
other_priv = clutter_color_state_get_instance_private (other_color_state);
if (priv->colorimetry.type == CLUTTER_COLORIMETRY_TYPE_COLORSPACE &&
other_priv->colorimetry.type == CLUTTER_COLORIMETRY_TYPE_COLORSPACE)
return priv->colorimetry.colorspace == other_priv->colorimetry.colorspace;
primaries = get_primaries (color_state);
other_primaries = get_primaries (other_color_state);
return chromaticity_equal (primaries->r_x, primaries->r_y,
other_primaries->r_x, other_primaries->r_y) &&
chromaticity_equal (primaries->g_x, primaries->g_y,
other_primaries->g_x, other_primaries->g_y) &&
chromaticity_equal (primaries->b_x, primaries->b_y,
other_primaries->b_x, other_primaries->b_y) &&
chromaticity_equal (primaries->w_x, primaries->w_y,
other_primaries->w_x, other_primaries->w_y);
}
static gboolean
eotf_equal (ClutterColorState *color_state,
ClutterColorState *other_color_state)
{
ClutterColorStatePrivate *priv;
ClutterColorStatePrivate *other_priv;
priv = clutter_color_state_get_instance_private (color_state);
other_priv = clutter_color_state_get_instance_private (other_color_state);
if (priv->eotf.type == CLUTTER_EOTF_TYPE_NAMED &&
other_priv->eotf.type == CLUTTER_EOTF_TYPE_NAMED)
return priv->eotf.tf_name == other_priv->eotf.tf_name;
return FALSE;
}
gboolean
clutter_color_state_equals (ClutterColorState *color_state,
ClutterColorState *other_color_state)
{
if (color_state == other_color_state)
return TRUE;
if (color_state == NULL || other_color_state == NULL)
return FALSE;
g_return_val_if_fail (CLUTTER_IS_COLOR_STATE (color_state), FALSE);
g_return_val_if_fail (CLUTTER_IS_COLOR_STATE (other_color_state), FALSE);
return colorimetry_equal (color_state, other_color_state) &&
eotf_equal (color_state, other_color_state) &&
luminances_equal (color_state, other_color_state);
}
static char *
clutter_colorimetry_to_string (ClutterColorimetry colorimetry)
{
const ClutterPrimaries *primaries;
switch (colorimetry.type)
{
case CLUTTER_COLORIMETRY_TYPE_COLORSPACE:
return g_strdup (clutter_colorspace_to_string (colorimetry.colorspace));
case CLUTTER_COLORIMETRY_TYPE_PRIMARIES:
primaries = colorimetry.primaries;
return g_strdup_printf ("[R: %f, %f G: %f, %f B: %f, %f W: %f, %f]",
primaries->r_x, primaries->r_y,
primaries->g_x, primaries->g_y,
primaries->b_x, primaries->b_y,
primaries->w_x, primaries->w_y);
}
}
char *
clutter_color_state_to_string (ClutterColorState *color_state)
{
ClutterColorStatePrivate *priv;
g_autofree char *primaries_name = NULL;
const char *transfer_function_name;
const ClutterLuminance *lum;
g_return_val_if_fail (CLUTTER_IS_COLOR_STATE (color_state), FALSE);
priv = clutter_color_state_get_instance_private (color_state);
primaries_name = clutter_colorimetry_to_string (priv->colorimetry);
transfer_function_name = clutter_eotf_to_string (priv->eotf);
lum = clutter_color_state_get_luminance (color_state);
return g_strdup_printf ("ClutterColorState %d "
"(primaries: %s, transfer function: %s, "
"min lum: %f, max lum: %f, ref lum: %f)",
priv->id,
primaries_name,
transfer_function_name,
lum->min,
lum->max,
lum->ref);
}
ClutterEncodingRequiredFormat
clutter_color_state_required_format (ClutterColorState *color_state)
{
ClutterColorStatePrivate *priv;
g_return_val_if_fail (CLUTTER_IS_COLOR_STATE (color_state), FALSE);
priv = clutter_color_state_get_instance_private (color_state);
switch (priv->eotf.tf_name)
{
case CLUTTER_TRANSFER_FUNCTION_LINEAR:
return CLUTTER_ENCODING_REQUIRED_FORMAT_FP16;
case CLUTTER_TRANSFER_FUNCTION_PQ:
return CLUTTER_ENCODING_REQUIRED_FORMAT_UINT10;
case CLUTTER_TRANSFER_FUNCTION_SRGB:
return CLUTTER_ENCODING_REQUIRED_FORMAT_UINT8;
}
g_assert_not_reached ();
}
/**
* clutter_color_state_get_blending:
* @color_state: a #ClutterColorState
* @force: if a linear variant should be forced
*
* Retrieves a variant of @color_state that is suitable for blending. This
* usually is a variant with linear transfer characteristics. If @color_state
* already is a #ClutterColorState suitable for blending, then @color_state is
* returned.
*
* Currently sRGB content is blended with sRGB and not with linear transfer
* characteristics.
*
* If @force is TRUE then linear transfer characteristics are used always.
*
* Returns: (transfer full): the #ClutterColorState suitable for blending
*/
ClutterColorState *
clutter_color_state_get_blending (ClutterColorState *color_state,
gboolean force)
{
ClutterColorStatePrivate *priv;
ClutterTransferFunction blending_tf;
ClutterColorspace colorspace;
ClutterPrimaries *primaries;
g_return_val_if_fail (CLUTTER_IS_COLOR_STATE (color_state), FALSE);
priv = clutter_color_state_get_instance_private (color_state);
switch (priv->eotf.tf_name)
{
case CLUTTER_TRANSFER_FUNCTION_PQ:
case CLUTTER_TRANSFER_FUNCTION_LINEAR:
blending_tf = CLUTTER_TRANSFER_FUNCTION_LINEAR;
break;
/* effectively this means we will blend sRGB content in sRGB, not linear */
case CLUTTER_TRANSFER_FUNCTION_SRGB:
blending_tf = priv->eotf.tf_name;
break;
default:
g_assert_not_reached ();
}
if (force)
blending_tf = CLUTTER_TRANSFER_FUNCTION_LINEAR;
if (priv->eotf.tf_name == blending_tf)
return g_object_ref (color_state);
switch (priv->colorimetry.type)
{
case CLUTTER_COLORIMETRY_TYPE_COLORSPACE:
colorspace = priv->colorimetry.colorspace;
primaries = NULL;
break;
case CLUTTER_COLORIMETRY_TYPE_PRIMARIES:
colorspace = CLUTTER_COLORSPACE_SRGB;
primaries = priv->colorimetry.primaries;
break;
}
return clutter_color_state_new_full (priv->context,
colorspace,
blending_tf,
primaries,
priv->luminance.min,
priv->luminance.max,
priv->luminance.ref);
}
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