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/*
* 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
#ifdef __HAIR__
/* curve attributes */
ccl_device float curve_attribute_float(KernelGlobals *kg, const ShaderData *sd, AttributeElement elem, int offset, float *dx, float *dy)
{
if(elem == ATTR_ELEMENT_CURVE) {
#ifdef __RAY_DIFFERENTIALS__
if(dx) *dx = 0.0f;
if(dy) *dy = 0.0f;
#endif
return kernel_tex_fetch(__attributes_float, offset + sd->prim);
}
else if(elem == ATTR_ELEMENT_CURVE_KEY) {
float4 curvedata = kernel_tex_fetch(__curves, sd->prim);
int k0 = __float_as_int(curvedata.x) + sd->segment;
int k1 = k0 + 1;
float f0 = kernel_tex_fetch(__attributes_float, offset + k0);
float f1 = kernel_tex_fetch(__attributes_float, offset + k1);
#ifdef __RAY_DIFFERENTIALS__
if(dx) *dx = sd->du.dx*(f1 - f0);
if(dy) *dy = 0.0f;
#endif
return (1.0f - sd->u)*f0 + sd->u*f1;
}
else {
#ifdef __RAY_DIFFERENTIALS__
if(dx) *dx = 0.0f;
if(dy) *dy = 0.0f;
#endif
return 0.0f;
}
}
ccl_device float3 curve_attribute_float3(KernelGlobals *kg, const ShaderData *sd, AttributeElement elem, int offset, float3 *dx, float3 *dy)
{
if(elem == ATTR_ELEMENT_CURVE) {
/* idea: we can't derive any useful differentials here, but for tiled
* mipmap image caching it would be useful to avoid reading the highest
* detail level always. maybe a derivative based on the hair density
* could be computed somehow? */
#ifdef __RAY_DIFFERENTIALS__
if(dx) *dx = make_float3(0.0f, 0.0f, 0.0f);
if(dy) *dy = make_float3(0.0f, 0.0f, 0.0f);
#endif
return float4_to_float3(kernel_tex_fetch(__attributes_float3, offset + sd->prim));
}
else if(elem == ATTR_ELEMENT_CURVE_KEY) {
float4 curvedata = kernel_tex_fetch(__curves, sd->prim);
int k0 = __float_as_int(curvedata.x) + sd->segment;
int k1 = k0 + 1;
float3 f0 = float4_to_float3(kernel_tex_fetch(__attributes_float3, offset + k0));
float3 f1 = float4_to_float3(kernel_tex_fetch(__attributes_float3, offset + k1));
#ifdef __RAY_DIFFERENTIALS__
if(dx) *dx = sd->du.dx*(f1 - f0);
if(dy) *dy = make_float3(0.0f, 0.0f, 0.0f);
#endif
return (1.0f - sd->u)*f0 + sd->u*f1;
}
else {
#ifdef __RAY_DIFFERENTIALS__
if(dx) *dx = make_float3(0.0f, 0.0f, 0.0f);
if(dy) *dy = make_float3(0.0f, 0.0f, 0.0f);
#endif
return make_float3(0.0f, 0.0f, 0.0f);
}
}
/* hair info node functions */
ccl_device float curve_thickness(KernelGlobals *kg, ShaderData *sd)
{
float r = 0.0f;
if(sd->segment != ~0) {
float4 curvedata = kernel_tex_fetch(__curves, sd->prim);
int k0 = __float_as_int(curvedata.x) + sd->segment;
int k1 = k0 + 1;
float4 P1 = kernel_tex_fetch(__curve_keys, k0);
float4 P2 = kernel_tex_fetch(__curve_keys, k1);
r = (P2.w - P1.w) * sd->u + P1.w;
}
return r*2.0f;
}
ccl_device float3 curve_tangent_normal(KernelGlobals *kg, ShaderData *sd)
{
float3 tgN = make_float3(0.0f,0.0f,0.0f);
if(sd->segment != ~0) {
tgN = -(-sd->I - sd->dPdu * (dot(sd->dPdu,-sd->I) / len_squared(sd->dPdu)));
tgN = normalize(tgN);
/* need to find suitable scaled gd for corrected normal */
#if 0
tgN = normalize(tgN - gd * sd->dPdu);
#endif
}
return tgN;
}
#endif
CCL_NAMESPACE_END
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