forked from bartvdbraak/blender
85 lines
3.4 KiB
C
85 lines
3.4 KiB
C
/*
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* Adapted from Open Shading Language with this license:
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*
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* Copyright (c) 2009-2010 Sony Pictures Imageworks Inc., et al.
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* All Rights Reserved.
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*
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* Modifications Copyright 2013, Blender Foundation.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of Sony Pictures Imageworks nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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CCL_NAMESPACE_BEGIN
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/* Blackbody Node */
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ccl_device void svm_node_blackbody(KernelGlobals *kg, ShaderData *sd, float *stack, uint temperature_offset, uint col_offset)
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{
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/* Output */
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float3 color_rgb = make_float3(0.0f, 0.0f, 0.0f);
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/* Input */
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float temperature = stack_load_float(stack, temperature_offset);
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if (temperature < BB_DRAPER) {
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/* just return very very dim red */
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color_rgb = make_float3(1.0e-6f,0.0f,0.0f);
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}
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else if (temperature <= BB_MAX_TABLE_RANGE) {
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/* This is the overall size of the table */
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const int lookuptablesize = 956;
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const float lookuptablenormalize = 1.0f/956.0f;
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/* reconstruct a proper index for the table lookup, compared to OSL we don't look up two colors
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just one (the OSL-lerp is also automatically done for us by "lookup_table_read") */
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float t = powf((temperature - BB_DRAPER) * (1.0f / BB_TABLE_SPACING), (1.0f / BB_TABLE_XPOWER));
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int blackbody_table_offset = kernel_data.tables.blackbody_offset;
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/* Retrieve colors from the lookup table */
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float lutval = t*lookuptablenormalize;
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float R = lookup_table_read(kg, lutval, blackbody_table_offset, lookuptablesize);
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lutval = (t + 319.0f*1.0f)*lookuptablenormalize;
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float G = lookup_table_read(kg, lutval, blackbody_table_offset, lookuptablesize);
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lutval = (t + 319.0f*2.0f)*lookuptablenormalize;
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float B = lookup_table_read(kg, lutval, blackbody_table_offset, lookuptablesize);
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R = powf(R, BB_TABLE_YPOWER);
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G = powf(G, BB_TABLE_YPOWER);
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B = powf(B, BB_TABLE_YPOWER);
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color_rgb = make_float3(R, G, B);
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}
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/* Luminance */
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float l = linear_rgb_to_gray(color_rgb);
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if (l != 0.0f)
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color_rgb /= l;
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if (stack_valid(col_offset))
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stack_store_float3(stack, col_offset, color_rgb);
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}
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CCL_NAMESPACE_END
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