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Diffstat (limited to 'intern/cycles/kernel/sample/sample_lcg.h')
-rw-r--r-- | intern/cycles/kernel/sample/sample_lcg.h | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/intern/cycles/kernel/sample/sample_lcg.h b/intern/cycles/kernel/sample/sample_lcg.h new file mode 100644 index 00000000000..92cfff639b4 --- /dev/null +++ b/intern/cycles/kernel/sample/sample_lcg.h @@ -0,0 +1,51 @@ +/* + * Copyright 2011-2013 Blender Foundation + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +#pragma once + +CCL_NAMESPACE_BEGIN + +/* Linear Congruential Generator */ + +ccl_device uint lcg_step_uint(uint *rng) +{ + /* implicit mod 2^32 */ + *rng = (1103515245 * (*rng) + 12345); + return *rng; +} + +ccl_device float lcg_step_float(uint *rng) +{ + /* implicit mod 2^32 */ + *rng = (1103515245 * (*rng) + 12345); + return (float)*rng * (1.0f / (float)0xFFFFFFFF); +} + +ccl_device uint lcg_init(uint seed) +{ + uint rng = seed; + lcg_step_uint(&rng); + return rng; +} + +ccl_device_inline uint lcg_state_init(const uint rng_hash, + const uint rng_offset, + const uint sample, + const uint scramble) +{ + return lcg_init(rng_hash + rng_offset + sample * scramble); +} + +CCL_NAMESPACE_END |