diff options
Diffstat (limited to 'intern/cycles/kernel/svm/ies.h')
| -rw-r--r-- | intern/cycles/kernel/svm/ies.h | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/intern/cycles/kernel/svm/ies.h b/intern/cycles/kernel/svm/ies.h new file mode 100644 index 00000000000..f0923720878 --- /dev/null +++ b/intern/cycles/kernel/svm/ies.h @@ -0,0 +1,122 @@ +/* + * 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 + +/* IES Light */ + +ccl_device_inline float interpolate_ies_vertical( + KernelGlobals kg, int ofs, int v, int v_num, float v_frac, int h) +{ + /* Since lookups are performed in spherical coordinates, clamping the coordinates at the low end + * of v (corresponding to the north pole) would result in artifacts. The proper way of dealing + * with this would be to lookup the corresponding value on the other side of the pole, but since + * the horizontal coordinates might be nonuniform, this would require yet another interpolation. + * Therefore, the assumption is made that the light is going to be symmetrical, which means that + * we can just take the corresponding value at the current horizontal coordinate. */ + +#define IES_LOOKUP(v) kernel_tex_fetch(__ies, ofs + h * v_num + (v)) + /* If v is zero, assume symmetry and read at v=1 instead of v=-1. */ + float a = IES_LOOKUP((v == 0) ? 1 : v - 1); + float b = IES_LOOKUP(v); + float c = IES_LOOKUP(v + 1); + float d = IES_LOOKUP(min(v + 2, v_num - 1)); +#undef IES_LOOKUP + + return cubic_interp(a, b, c, d, v_frac); +} + +ccl_device_inline float kernel_ies_interp(KernelGlobals kg, int slot, float h_angle, float v_angle) +{ + /* Find offset of the IES data in the table. */ + int ofs = __float_as_int(kernel_tex_fetch(__ies, slot)); + if (ofs == -1) { + return 100.0f; + } + + int h_num = __float_as_int(kernel_tex_fetch(__ies, ofs++)); + int v_num = __float_as_int(kernel_tex_fetch(__ies, ofs++)); + +#define IES_LOOKUP_ANGLE_H(h) kernel_tex_fetch(__ies, ofs + (h)) +#define IES_LOOKUP_ANGLE_V(v) kernel_tex_fetch(__ies, ofs + h_num + (v)) + + /* Check whether the angle is within the bounds of the IES texture. */ + if (v_angle >= IES_LOOKUP_ANGLE_V(v_num - 1)) { + return 0.0f; + } + kernel_assert(v_angle >= IES_LOOKUP_ANGLE_V(0)); + kernel_assert(h_angle >= IES_LOOKUP_ANGLE_H(0)); + kernel_assert(h_angle <= IES_LOOKUP_ANGLE_H(h_num - 1)); + + /* Lookup the angles to find the table position. */ + int h_i, v_i; + /* TODO(lukas): Consider using bisection. + * Probably not worth it for the vast majority of IES files. */ + for (h_i = 0; IES_LOOKUP_ANGLE_H(h_i + 1) < h_angle; h_i++) + ; + for (v_i = 0; IES_LOOKUP_ANGLE_V(v_i + 1) < v_angle; v_i++) + ; + + float h_frac = inverse_lerp(IES_LOOKUP_ANGLE_H(h_i), IES_LOOKUP_ANGLE_H(h_i + 1), h_angle); + float v_frac = inverse_lerp(IES_LOOKUP_ANGLE_V(v_i), IES_LOOKUP_ANGLE_V(v_i + 1), v_angle); + +#undef IES_LOOKUP_ANGLE_H +#undef IES_LOOKUP_ANGLE_V + + /* Skip forward to the actual intensity data. */ + ofs += h_num + v_num; + + /* Perform cubic interpolation along the horizontal coordinate to get the intensity value. + * If h_i is zero, just wrap around since the horizontal angles always go over the full circle. + * However, the last entry (360°) equals the first one, so we need to wrap around to the one + * before that. */ + float a = interpolate_ies_vertical( + kg, ofs, v_i, v_num, v_frac, (h_i == 0) ? h_num - 2 : h_i - 1); + float b = interpolate_ies_vertical(kg, ofs, v_i, v_num, v_frac, h_i); + float c = interpolate_ies_vertical(kg, ofs, v_i, v_num, v_frac, h_i + 1); + /* Same logic here, wrap around to the second element if necessary. */ + float d = interpolate_ies_vertical( + kg, ofs, v_i, v_num, v_frac, (h_i + 2 == h_num) ? 1 : h_i + 2); + + /* Cubic interpolation can result in negative values, so get rid of them. */ + return max(cubic_interp(a, b, c, d, h_frac), 0.0f); +} + +ccl_device_noinline void svm_node_ies(KernelGlobals kg, + ccl_private ShaderData *sd, + ccl_private float *stack, + uint4 node) +{ + uint vector_offset, strength_offset, fac_offset, slot = node.z; + svm_unpack_node_uchar3(node.y, &strength_offset, &vector_offset, &fac_offset); + + float3 vector = stack_load_float3(stack, vector_offset); + float strength = stack_load_float_default(stack, strength_offset, node.w); + + vector = normalize(vector); + float v_angle = safe_acosf(-vector.z); + float h_angle = atan2f(vector.x, vector.y) + M_PI_F; + + float fac = strength * kernel_ies_interp(kg, slot, h_angle, v_angle); + + if (stack_valid(fac_offset)) { + stack_store_float(stack, fac_offset, fac); + } +} + +CCL_NAMESPACE_END |