Cycles: better path termination for transparency.
[blender.git] / intern / cycles / kernel / closure / bsdf_transparent.h
1 /*
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32
33 #ifndef __BSDF_TRANSPARENT_H__
34 #define __BSDF_TRANSPARENT_H__
35
36 CCL_NAMESPACE_BEGIN
37
38 ccl_device void bsdf_transparent_setup(ShaderData *sd, const float3 weight, int path_flag)
39 {
40         if(sd->flag & SD_TRANSPARENT) {
41                 sd->closure_transparent_extinction += weight;
42
43                 for(int i = 0; i < sd->num_closure; i++) {
44                         ShaderClosure *sc = &sd->closure[i];
45
46                         if(sc->type == CLOSURE_BSDF_TRANSPARENT_ID) {
47                                 sc->weight += weight;
48                                 sc->sample_weight += fabsf(average(weight));
49                                 break;
50                         }
51                 }
52         }
53         else {
54                 sd->flag |= SD_BSDF|SD_TRANSPARENT;
55                 sd->closure_transparent_extinction = weight;
56
57                 if(path_flag & PATH_RAY_TERMINATE) {
58                         /* In this case the number of closures is set to zero to disable
59                          * all others, but we still want to get transparency so increase
60                          * the number just for this. */
61                         sd->num_closure_left = 1;
62                 }
63
64                 ShaderClosure *bsdf = bsdf_alloc(sd, sizeof(ShaderClosure), weight);
65
66                 if(bsdf) {
67                         bsdf->N = sd->N;
68                         bsdf->type = CLOSURE_BSDF_TRANSPARENT_ID;
69                 }
70         }
71 }
72
73 ccl_device float3 bsdf_transparent_eval_reflect(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
74 {
75         return make_float3(0.0f, 0.0f, 0.0f);
76 }
77
78 ccl_device float3 bsdf_transparent_eval_transmit(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
79 {
80         return make_float3(0.0f, 0.0f, 0.0f);
81 }
82
83 ccl_device int bsdf_transparent_sample(const ShaderClosure *sc, float3 Ng, float3 I, float3 dIdx, float3 dIdy, float randu, float randv, float3 *eval, float3 *omega_in, float3 *domega_in_dx, float3 *domega_in_dy, float *pdf)
84 {
85         // only one direction is possible
86         *omega_in = -I;
87 #ifdef __RAY_DIFFERENTIALS__
88         *domega_in_dx = -dIdx;
89         *domega_in_dy = -dIdy;
90 #endif
91         *pdf = 1;
92         *eval = make_float3(1, 1, 1);
93         return LABEL_TRANSMIT|LABEL_TRANSPARENT;
94 }
95
96 CCL_NAMESPACE_END
97
98 #endif /* __BSDF_TRANSPARENT_H__ */
99