/* 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); } }