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/*
* Copyright 2011, Blender Foundation.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include "stdosl.h"
#include "node_color.h"
color image_texture_lookup(string filename, string color_space, float u, float v, output float Alpha)
{
color rgb = (color)texture(filename, u, 1.0 - v, "wrap", "periodic", "alpha", Alpha);
if (color_space == "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 color_space = "sRGB",
string projection = "Flat",
float projection_blend = 0.0,
output color Color = color(0.0, 0.0, 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, color_space, p[0], p[1], Alpha);
}
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);
}
}
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, color_space, p[1], p[2], tmp_alpha);
Alpha += weight[0]*tmp_alpha;
}
if (weight[1] > 0.0) {
Color += weight[1]*image_texture_lookup(filename, color_space, p[0], p[2], tmp_alpha);
Alpha += weight[1]*tmp_alpha;
}
if (weight[2] > 0.0) {
Color += weight[2]*image_texture_lookup(filename, color_space, p[1], p[0], tmp_alpha);
Alpha += weight[2]*tmp_alpha;
}
}
}
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