blender/intern/cycles/kernel/kernel_curve.h
Brecht Van Lommel bf25f1ea96 Cycles Hair: refactoring to store curves with the index of the first key and the
number of keys in the curve, rather than curve segments with the indices of two
keys. ShaderData.segment now stores the segment number in the curve.
2013-01-03 12:09:09 +00:00

142 lines
3.9 KiB
C

/*
* Copyright 2011, Blender Foundation.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
CCL_NAMESPACE_BEGIN
#ifdef __HAIR__
/* curve attributes */
__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;
}
}
__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 */
__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;
}
__device float3 curve_tangent_normal(KernelGlobals *kg, ShaderData *sd)
{
float3 tgN = make_float3(0.0f,0.0f,0.0f);
if(sd->segment != ~0) {
float normalmix = kernel_data.curve_kernel_data.normalmix;
tgN = -(-sd->I - sd->dPdu * (dot(sd->dPdu,-sd->I) * normalmix / len_squared(sd->dPdu)));
tgN = normalize(tgN);
/* need to find suitable scaled gd for corrected normal */
#if 0
if (kernel_data.curve_kernel_data.use_tangent_normal_correction)
tgN = normalize(tgN - gd * sd->dPdu);
#endif
}
return tgN;
}
#endif
CCL_NAMESPACE_END