forked from bartvdbraak/blender
Brecht Van Lommel
27043b8e40
These are internally stored as a 3D image textures, but accessible like e.g. UV coordinates though the attribute node and getattribute(). This is convenient for rendering e.g. smoke objects where data like density is really a property of the mesh, and it avoids having to specify the smoke object in a texture node, instead the material will work with any smoke domain.
76 lines
2.4 KiB
C
76 lines
2.4 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 float3 volume_normalized_position(KernelGlobals *kg, const ShaderData *sd, 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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AttributeElement attr_elem;
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int attr_offset = find_attribute(kg, sd, ATTR_STD_GENERATED_TRANSFORM, &attr_elem);
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object_inverse_position_transform(kg, sd, &P);
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if(attr_offset != ATTR_STD_NOT_FOUND) {
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Transform tfm = primitive_attribute_matrix(kg, sd, attr_offset);
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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, AttributeElement elem, int id, 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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float4 r = kernel_tex_image_interp_3d(id, P.x, P.y, P.z);
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if(dx) *dx = 0.0f;
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if(dx) *dy = 0.0f;
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/* todo: support float textures to lower memory usage for single floats */
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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, AttributeElement elem, int id, 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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float4 r = kernel_tex_image_interp_3d(id, P.x, P.y, P.z);
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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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