diff options
Diffstat (limited to 'intern/cycles/kernel/bvh/bvh_util.h')
| -rw-r--r-- | intern/cycles/kernel/bvh/bvh_util.h | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/intern/cycles/kernel/bvh/bvh_util.h b/intern/cycles/kernel/bvh/bvh_util.h index 869311b38e2..309f0eeb1e2 100644 --- a/intern/cycles/kernel/bvh/bvh_util.h +++ b/intern/cycles/kernel/bvh/bvh_util.h @@ -195,4 +195,32 @@ ccl_device_inline int intersection_find_attribute(KernelGlobals kg, return (attr_map.y == ATTR_ELEMENT_NONE) ? (int)ATTR_STD_NOT_FOUND : (int)attr_map.z; } +/* Transparent Shadows */ + +/* Cut-off value to stop transparent shadow tracing when practically opaque. */ +#define CURVE_SHADOW_TRANSPARENCY_CUTOFF 0.001f + +ccl_device_inline float intersection_curve_shadow_transparency(KernelGlobals kg, + const int object, + const int prim, + const float u) +{ + /* Find attribute. */ + const int offset = intersection_find_attribute(kg, object, ATTR_STD_SHADOW_TRANSPARENCY); + if (offset == ATTR_STD_NOT_FOUND) { + /* If no shadow transparency attribute, assume opaque. */ + return 0.0f; + } + + /* Interpolate transparency between curve keys. */ + const KernelCurve kcurve = kernel_tex_fetch(__curves, prim); + const int k0 = kcurve.first_key + PRIMITIVE_UNPACK_SEGMENT(kcurve.type); + const int k1 = k0 + 1; + + const float f0 = kernel_tex_fetch(__attributes_float, offset + k0); + const float f1 = kernel_tex_fetch(__attributes_float, offset + k1); + + return (1.0f - u) * f0 + u * f1; +} + CCL_NAMESPACE_END |