forked from bartvdbraak/blender
Brecht Van Lommel
eff3bd4e98
The same can be achieved by flipping normals on the mesh, but it can be convenient to do this in the shader.
75 lines
2.2 KiB
C
75 lines
2.2 KiB
C
/*
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* Copyright 2011-2013 Blender Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License
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*/
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CCL_NAMESPACE_BEGIN
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/* Fresnel Node */
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ccl_device void svm_node_fresnel(ShaderData *sd, float *stack, uint ior_offset, uint ior_value, uint node)
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{
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uint normal_offset, out_offset;
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decode_node_uchar4(node, &normal_offset, &out_offset, NULL, NULL);
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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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float3 normal_in = stack_valid(normal_offset)? stack_load_float3(stack, normal_offset): sd->N;
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eta = fmaxf(eta, 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, normal_in), eta);
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stack_store_float(stack, out_offset, f);
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}
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/* Layer Weight Node */
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ccl_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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uint type, normal_offset, out_offset;
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decode_node_uchar4(node.w, &type, &normal_offset, &out_offset, NULL);
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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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float3 normal_in = (stack_valid(normal_offset))? stack_load_float3(stack, normal_offset): sd->N;
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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, normal_in), eta);
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}
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else {
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f = fabsf(dot(sd->I, normal_in));
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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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