forked from bartvdbraak/blender
71 lines
2.0 KiB
C
71 lines
2.0 KiB
C
/*
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* Copyright 2011, Blender Foundation.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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CCL_NAMESPACE_BEGIN
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/* Fresnel Node */
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__device void svm_node_fresnel(ShaderData *sd, float *stack, uint ior_offset, uint ior_value, uint out_offset)
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{
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float eta = (stack_valid(ior_offset))? stack_load_float(stack, ior_offset): __uint_as_float(ior_value);
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eta = fmaxf(eta, 1.0f + 1e-5f);
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eta = (sd->flag & SD_BACKFACING)? 1.0f/eta: eta;
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float f = fresnel_dielectric_cos(dot(sd->I, sd->N), eta);
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stack_store_float(stack, out_offset, f);
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}
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/* Blend Weight Node */
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__device void svm_node_layer_weight(ShaderData *sd, float *stack, uint4 node)
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{
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uint blend_offset = node.y;
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uint blend_value = node.z;
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float blend = (stack_valid(blend_offset))? stack_load_float(stack, blend_offset): __uint_as_float(blend_value);
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uint type, out_offset;
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decode_node_uchar4(node.w, &type, &out_offset, NULL, NULL);
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float f;
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if(type == NODE_LAYER_WEIGHT_FRESNEL) {
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float eta = fmaxf(1.0f - blend, 1e-5f);
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eta = (sd->flag & SD_BACKFACING)? eta: 1.0f/eta;
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f = fresnel_dielectric_cos(dot(sd->I, sd->N), eta);
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}
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else {
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f = fabsf(dot(sd->I, sd->N));
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if(blend != 0.5f) {
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blend = clamp(blend, 0.0f, 1.0f-1e-5f);
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blend = (blend < 0.5f)? 2.0f*blend: 0.5f/(1.0f - blend);
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f = powf(f, blend);
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}
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f = 1.0f - f;
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}
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stack_store_float(stack, out_offset, f);
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}
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CCL_NAMESPACE_END
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