forked from bartvdbraak/blender
b9ce231060
More information in this post: http://code.blender.org/ Thanks to all contributes for giving their permission!
138 lines
3.6 KiB
C
138 lines
3.6 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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#ifdef __HAIR__
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/* curve attributes */
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__device float curve_attribute_float(KernelGlobals *kg, const ShaderData *sd, AttributeElement elem, int offset, float *dx, float *dy)
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{
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if(elem == ATTR_ELEMENT_CURVE) {
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#ifdef __RAY_DIFFERENTIALS__
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if(dx) *dx = 0.0f;
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if(dy) *dy = 0.0f;
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#endif
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return kernel_tex_fetch(__attributes_float, offset + sd->prim);
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}
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else if(elem == ATTR_ELEMENT_CURVE_KEY) {
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float4 curvedata = kernel_tex_fetch(__curves, sd->prim);
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int k0 = __float_as_int(curvedata.x) + sd->segment;
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int k1 = k0 + 1;
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float f0 = kernel_tex_fetch(__attributes_float, offset + k0);
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float f1 = kernel_tex_fetch(__attributes_float, offset + k1);
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#ifdef __RAY_DIFFERENTIALS__
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if(dx) *dx = sd->du.dx*(f1 - f0);
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if(dy) *dy = 0.0f;
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#endif
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return (1.0f - sd->u)*f0 + sd->u*f1;
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}
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else {
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#ifdef __RAY_DIFFERENTIALS__
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if(dx) *dx = 0.0f;
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if(dy) *dy = 0.0f;
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#endif
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return 0.0f;
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}
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}
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__device float3 curve_attribute_float3(KernelGlobals *kg, const ShaderData *sd, AttributeElement elem, int offset, float3 *dx, float3 *dy)
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{
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if(elem == ATTR_ELEMENT_CURVE) {
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/* idea: we can't derive any useful differentials here, but for tiled
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* mipmap image caching it would be useful to avoid reading the highest
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* detail level always. maybe a derivative based on the hair density
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* could be computed somehow? */
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#ifdef __RAY_DIFFERENTIALS__
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if(dx) *dx = make_float3(0.0f, 0.0f, 0.0f);
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if(dy) *dy = make_float3(0.0f, 0.0f, 0.0f);
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#endif
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return float4_to_float3(kernel_tex_fetch(__attributes_float3, offset + sd->prim));
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}
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else if(elem == ATTR_ELEMENT_CURVE_KEY) {
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float4 curvedata = kernel_tex_fetch(__curves, sd->prim);
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int k0 = __float_as_int(curvedata.x) + sd->segment;
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int k1 = k0 + 1;
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float3 f0 = float4_to_float3(kernel_tex_fetch(__attributes_float3, offset + k0));
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float3 f1 = float4_to_float3(kernel_tex_fetch(__attributes_float3, offset + k1));
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#ifdef __RAY_DIFFERENTIALS__
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if(dx) *dx = sd->du.dx*(f1 - f0);
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if(dy) *dy = make_float3(0.0f, 0.0f, 0.0f);
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#endif
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return (1.0f - sd->u)*f0 + sd->u*f1;
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}
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else {
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#ifdef __RAY_DIFFERENTIALS__
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if(dx) *dx = make_float3(0.0f, 0.0f, 0.0f);
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if(dy) *dy = make_float3(0.0f, 0.0f, 0.0f);
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#endif
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return make_float3(0.0f, 0.0f, 0.0f);
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}
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}
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/* hair info node functions */
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__device float curve_thickness(KernelGlobals *kg, ShaderData *sd)
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{
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float r = 0.0f;
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if(sd->segment != ~0) {
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float4 curvedata = kernel_tex_fetch(__curves, sd->prim);
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int k0 = __float_as_int(curvedata.x) + sd->segment;
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int k1 = k0 + 1;
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float4 P1 = kernel_tex_fetch(__curve_keys, k0);
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float4 P2 = kernel_tex_fetch(__curve_keys, k1);
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r = (P2.w - P1.w) * sd->u + P1.w;
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}
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return r*2.0f;
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}
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__device float3 curve_tangent_normal(KernelGlobals *kg, ShaderData *sd)
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{
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float3 tgN = make_float3(0.0f,0.0f,0.0f);
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if(sd->segment != ~0) {
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tgN = -(-sd->I - sd->dPdu * (dot(sd->dPdu,-sd->I) / len_squared(sd->dPdu)));
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tgN = normalize(tgN);
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/* need to find suitable scaled gd for corrected normal */
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#if 0
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tgN = normalize(tgN - gd * sd->dPdu);
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#endif
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}
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return tgN;
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}
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#endif
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CCL_NAMESPACE_END
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