Brecht Van Lommel
006025ead0
This is not yet fully supported by automatic volume bounds but works fine in most cases that will have mostly matching bounds. Ref T73201
87 lines
3.1 KiB
C++
87 lines
3.1 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,
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const ShaderData *sd,
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const AttributeDescriptor desc)
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{
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/* todo: optimize this so we don't have to transform both here and in
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* kernel_tex_image_interp_3d when possible. Also could optimize for the
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* common case where transform is translation/scale only. */
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float3 P = sd->P;
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object_inverse_position_transform(kg, sd, &P);
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InterpolationType interp = (sd->flag & SD_VOLUME_CUBIC) ? INTERPOLATION_CUBIC :
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INTERPOLATION_NONE;
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float4 r = kernel_tex_image_interp_3d(kg, desc.offset, P, interp);
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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,
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const ShaderData *sd,
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const AttributeDescriptor desc)
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{
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float3 P = sd->P;
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object_inverse_position_transform(kg, sd, &P);
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InterpolationType interp = (sd->flag & SD_VOLUME_CUBIC) ? INTERPOLATION_CUBIC :
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INTERPOLATION_NONE;
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float4 r = kernel_tex_image_interp_3d(kg, desc.offset, P, interp);
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if (r.w > 1e-6f && r.w != 1.0f) {
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/* For RGBA colors, unpremultiply after interpolation. */
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return float4_to_float3(r) / r.w;
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}
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else {
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return float4_to_float3(r);
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}
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}
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#endif
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CCL_NAMESPACE_END
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