forked from bartvdbraak/blender
Brecht Van Lommel
2d92988f6b
While cubic interpolation is quite expensive on the CPU compared to linear interpolation, the difference on the GPU is quite small.
78 lines
2.7 KiB
C
78 lines
2.7 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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/* Volume Primitive
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*
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* Volumes are just regions inside meshes with the mesh surface as boundaries.
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* There isn't as much data to access as for surfaces, there is only a position
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* to do lookups in 3D voxel or procedural textures.
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*
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* 3D voxel textures can be assigned as attributes per mesh, which means the
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* same shader can be used for volume objects with different densities, etc. */
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CCL_NAMESPACE_BEGIN
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#ifdef __VOLUME__
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/* Return position normalized to 0..1 in mesh bounds */
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ccl_device_inline float3 volume_normalized_position(KernelGlobals *kg,
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const ShaderData *sd,
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float3 P)
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{
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/* todo: optimize this so it's just a single matrix multiplication when
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* possible (not motion blur), or perhaps even just translation + scale */
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const AttributeDescriptor desc = find_attribute(kg, sd, ATTR_STD_GENERATED_TRANSFORM);
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object_inverse_position_transform(kg, sd, &P);
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if(desc.offset != ATTR_STD_NOT_FOUND) {
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Transform tfm = primitive_attribute_matrix(kg, sd, desc);
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P = transform_point(&tfm, P);
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}
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return P;
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}
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ccl_device float volume_attribute_float(KernelGlobals *kg, const ShaderData *sd, const AttributeDescriptor desc, float *dx, float *dy)
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{
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float3 P = volume_normalized_position(kg, sd, sd->P);
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InterpolationType interp = (sd->flag & SD_VOLUME_CUBIC)? INTERPOLATION_CUBIC: INTERPOLATION_NONE;
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float4 r = kernel_tex_image_interp_3d(kg, desc.offset, P.x, P.y, P.z, interp);
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if(dx) *dx = 0.0f;
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if(dy) *dy = 0.0f;
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return average(float4_to_float3(r));
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}
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ccl_device float3 volume_attribute_float3(KernelGlobals *kg, const ShaderData *sd, const AttributeDescriptor desc, float3 *dx, float3 *dy)
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{
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float3 P = volume_normalized_position(kg, sd, sd->P);
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InterpolationType interp = (sd->flag & SD_VOLUME_CUBIC)? INTERPOLATION_CUBIC: INTERPOLATION_NONE;
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float4 r = kernel_tex_image_interp_3d(kg, desc.offset, P.x, P.y, P.z, interp);
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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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return float4_to_float3(r);
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}
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#endif
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CCL_NAMESPACE_END
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