blender/intern/cycles/kernel/svm/svm_fresnel.h
Brecht Van Lommel eff3bd4e98 Fix T38439: allow IOR in range [0, inf] instead of [1, inf] in Cycles.
The same can be achieved by flipping normals on the mesh, but it can be
convenient to do this in the shader.
2014-02-03 17:08:34 +01:00

75 lines
2.2 KiB
C

/*
* Copyright 2011-2013 Blender Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License
*/
CCL_NAMESPACE_BEGIN
/* Fresnel Node */
ccl_device void svm_node_fresnel(ShaderData *sd, float *stack, uint ior_offset, uint ior_value, uint node)
{
uint normal_offset, out_offset;
decode_node_uchar4(node, &normal_offset, &out_offset, NULL, NULL);
float eta = (stack_valid(ior_offset))? stack_load_float(stack, ior_offset): __uint_as_float(ior_value);
float3 normal_in = stack_valid(normal_offset)? stack_load_float3(stack, normal_offset): sd->N;
eta = fmaxf(eta, 1e-5f);
eta = (sd->flag & SD_BACKFACING)? 1.0f/eta: eta;
float f = fresnel_dielectric_cos(dot(sd->I, normal_in), eta);
stack_store_float(stack, out_offset, f);
}
/* Layer Weight Node */
ccl_device void svm_node_layer_weight(ShaderData *sd, float *stack, uint4 node)
{
uint blend_offset = node.y;
uint blend_value = node.z;
uint type, normal_offset, out_offset;
decode_node_uchar4(node.w, &type, &normal_offset, &out_offset, NULL);
float blend = (stack_valid(blend_offset))? stack_load_float(stack, blend_offset): __uint_as_float(blend_value);
float3 normal_in = (stack_valid(normal_offset))? stack_load_float3(stack, normal_offset): sd->N;
float f;
if(type == NODE_LAYER_WEIGHT_FRESNEL) {
float eta = fmaxf(1.0f - blend, 1e-5f);
eta = (sd->flag & SD_BACKFACING)? eta: 1.0f/eta;
f = fresnel_dielectric_cos(dot(sd->I, normal_in), eta);
}
else {
f = fabsf(dot(sd->I, normal_in));
if(blend != 0.5f) {
blend = clamp(blend, 0.0f, 1.0f-1e-5f);
blend = (blend < 0.5f)? 2.0f*blend: 0.5f/(1.0f - blend);
f = powf(f, blend);
}
f = 1.0f - f;
}
stack_store_float(stack, out_offset, f);
}
CCL_NAMESPACE_END