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/* SPDX-License-Identifier: Apache-2.0
* Copyright 2011-2022 Blender Foundation */
#include "node_color.h"
#include "stdcycles.h"
point texco_remap_square(point co)
{
return (co - point(0.5, 0.5, 0.5)) * 2.0;
}
point map_to_tube(vector dir)
{
float u, v;
v = (dir[2] + 1.0) * 0.5;
float len = sqrt(dir[0] * dir[0] + dir[1] * dir[1]);
if (len > 0.0) {
u = (1.0 - (atan2(dir[0] / len, dir[1] / len) / M_PI)) * 0.5;
}
else {
v = u = 0.0; /* To avoid un-initialized variables. */
}
return point(u, v, 0.0);
}
point map_to_sphere(vector dir)
{
float len = length(dir);
float v, u;
if (len > 0.0) {
if (dir[0] == 0.0 && dir[1] == 0.0) {
u = 0.0; /* Otherwise domain error. */
}
else {
u = (1.0 - atan2(dir[0], dir[1]) / M_PI) / 2.0;
}
v = 1.0 - acos(dir[2] / len) / M_PI;
}
else {
v = u = 0.0; /* To avoid un-initialized variables. */
}
return point(u, v, 0.0);
}
color image_texture_lookup(string filename,
float u,
float v,
output float Alpha,
int compress_as_srgb,
int ignore_alpha,
int unassociate_alpha,
int is_float,
int is_tiled,
string interpolation,
string extension)
{
/* Flip the y coordinate, but preserve UDIM tiles. */
float flip_v;
if (is_tiled) {
float v_i = (int)v;
flip_v = v_i + (1.0 - (v - v_i));
}
else {
flip_v = 1.0 - v;
}
color rgb = (color)texture(
filename, u, flip_v, "wrap", extension, "interp", interpolation, "alpha", Alpha);
if (ignore_alpha) {
Alpha = 1.0;
}
else if (unassociate_alpha) {
rgb = color_unpremultiply(rgb, Alpha);
if (!is_float)
rgb = min(rgb, 1.0);
}
if (compress_as_srgb) {
rgb = color_srgb_to_scene_linear(rgb);
}
return rgb;
}
shader node_image_texture(int use_mapping = 0,
matrix mapping = matrix(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0),
point Vector = P,
string filename = "",
string projection = "flat",
string interpolation = "smartcubic",
string extension = "periodic",
float projection_blend = 0.0,
int compress_as_srgb = 0,
int ignore_alpha = 0,
int unassociate_alpha = 0,
int is_tiled = 0,
int is_float = 1,
output color Color = 0.0,
output float Alpha = 1.0)
{
point p = Vector;
if (use_mapping)
p = transform(mapping, p);
if (projection == "flat") {
Color = image_texture_lookup(filename,
p[0],
p[1],
Alpha,
compress_as_srgb,
ignore_alpha,
unassociate_alpha,
is_float,
is_tiled,
interpolation,
extension);
}
else if (projection == "box") {
/* object space normal */
vector Nob = transform("world", "object", N);
/* project from direction vector to barycentric coordinates in triangles */
Nob = vector(fabs(Nob[0]), fabs(Nob[1]), fabs(Nob[2]));
Nob /= (Nob[0] + Nob[1] + Nob[2]);
/* basic idea is to think of this as a triangle, each corner representing
* one of the 3 faces of the cube. in the corners we have single textures,
* in between we blend between two textures, and in the middle we a blend
* between three textures.
*
* the `Nxyz` values are the barycentric coordinates in an equilateral
* triangle, which in case of blending, in the middle has a smaller
* equilateral triangle where 3 textures blend. this divides things into
* 7 zones, with an if () test for each zone. */
vector weight = vector(0.0, 0.0, 0.0);
float blend = projection_blend;
float limit = 0.5 * (1.0 + blend);
/* first test for corners with single texture */
if (Nob[0] > limit * (Nob[0] + Nob[1]) && Nob[0] > limit * (Nob[0] + Nob[2])) {
weight[0] = 1.0;
}
else if (Nob[1] > limit * (Nob[0] + Nob[1]) && Nob[1] > limit * (Nob[1] + Nob[2])) {
weight[1] = 1.0;
}
else if (Nob[2] > limit * (Nob[0] + Nob[2]) && Nob[2] > limit * (Nob[1] + Nob[2])) {
weight[2] = 1.0;
}
else if (blend > 0.0) {
/* in case of blending, test for mixes between two textures */
if (Nob[2] < (1.0 - limit) * (Nob[1] + Nob[0])) {
weight[0] = Nob[0] / (Nob[0] + Nob[1]);
weight[0] = clamp((weight[0] - 0.5 * (1.0 - blend)) / blend, 0.0, 1.0);
weight[1] = 1.0 - weight[0];
}
else if (Nob[0] < (1.0 - limit) * (Nob[1] + Nob[2])) {
weight[1] = Nob[1] / (Nob[1] + Nob[2]);
weight[1] = clamp((weight[1] - 0.5 * (1.0 - blend)) / blend, 0.0, 1.0);
weight[2] = 1.0 - weight[1];
}
else if (Nob[1] < (1.0 - limit) * (Nob[0] + Nob[2])) {
weight[0] = Nob[0] / (Nob[0] + Nob[2]);
weight[0] = clamp((weight[0] - 0.5 * (1.0 - blend)) / blend, 0.0, 1.0);
weight[2] = 1.0 - weight[0];
}
else {
/* last case, we have a mix between three */
weight[0] = ((2.0 - limit) * Nob[0] + (limit - 1.0)) / (2.0 * limit - 1.0);
weight[1] = ((2.0 - limit) * Nob[1] + (limit - 1.0)) / (2.0 * limit - 1.0);
weight[2] = ((2.0 - limit) * Nob[2] + (limit - 1.0)) / (2.0 * limit - 1.0);
}
}
else {
/* Desperate mode, no valid choice anyway, fallback to one side.*/
weight[0] = 1.0;
}
Color = color(0.0, 0.0, 0.0);
Alpha = 0.0;
float tmp_alpha;
if (weight[0] > 0.0) {
Color += weight[0] * image_texture_lookup(filename,
p[1],
p[2],
tmp_alpha,
compress_as_srgb,
ignore_alpha,
unassociate_alpha,
is_float,
0,
interpolation,
extension);
Alpha += weight[0] * tmp_alpha;
}
if (weight[1] > 0.0) {
Color += weight[1] * image_texture_lookup(filename,
p[0],
p[2],
tmp_alpha,
compress_as_srgb,
ignore_alpha,
unassociate_alpha,
is_float,
0,
interpolation,
extension);
Alpha += weight[1] * tmp_alpha;
}
if (weight[2] > 0.0) {
Color += weight[2] * image_texture_lookup(filename,
p[1],
p[0],
tmp_alpha,
compress_as_srgb,
ignore_alpha,
unassociate_alpha,
is_float,
0,
interpolation,
extension);
Alpha += weight[2] * tmp_alpha;
}
}
else if (projection == "sphere") {
point projected = map_to_sphere(texco_remap_square(p));
Color = image_texture_lookup(filename,
projected[0],
projected[1],
Alpha,
compress_as_srgb,
ignore_alpha,
unassociate_alpha,
is_float,
0,
interpolation,
extension);
}
else if (projection == "tube") {
point projected = map_to_tube(texco_remap_square(p));
Color = image_texture_lookup(filename,
projected[0],
projected[1],
Alpha,
compress_as_srgb,
ignore_alpha,
unassociate_alpha,
is_float,
0,
interpolation,
extension);
}
}
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