Cycles: add transparent shadow support, i.e. shadows through Transparent BSDF

[blender.git] / intern / cycles / kernel / kernel_path.h

diff --git a/intern/cycles/kernel/kernel_path.h b/intern/cycles/kernel/kernel_path.h
index e438780b1c84519edd9d31d84e332c5f7f372b35..c609f6f13fe3722b13beebeb1f631243f3b83747 100644 (file)
--- a/intern/cycles/kernel/kernel_path.h
+++ b/intern/cycles/kernel/kernel_path.h
@@ -70,7 +70,7 @@ typedef struct PathState {
 
 __device_inline void path_state_init(PathState *state)
 {
-       state->flag = PATH_RAY_CAMERA|PATH_RAY_SINGULAR;
+       state->flag = PATH_RAY_CAMERA|PATH_RAY_SINGULAR|PATH_RAY_MIS_SKIP;
        state->bounce = 0;
        state->diffuse_bounce = 0;
        state->glossy_bounce = 0;
@@ -78,7 +78,7 @@ __device_inline void path_state_init(PathState *state)
        state->transparent_bounce = 0;
 }
 
-__device_inline void path_state_next(PathState *state, int label)
+__device_inline void path_state_next(KernelGlobals *kg, PathState *state, int label)
 {
        /* ray through transparent keeps same flags from previous ray and is
           not counted as a regular bounce, transparent has separate max */
@@ -86,6 +86,9 @@ __device_inline void path_state_next(PathState *state, int label)
                state->flag |= PATH_RAY_TRANSPARENT;
                state->transparent_bounce++;
 
+               if(!kernel_data.integrator.transparent_shadows)
+                       state->flag |= PATH_RAY_MIS_SKIP;
+
                return;
        }
 
@@ -113,16 +116,16 @@ __device_inline void path_state_next(PathState *state, int label)
        /* diffuse/glossy/singular */
        if(label & LABEL_DIFFUSE) {
                state->flag |= PATH_RAY_DIFFUSE;
-               state->flag &= ~(PATH_RAY_GLOSSY|PATH_RAY_SINGULAR);
+               state->flag &= ~(PATH_RAY_GLOSSY|PATH_RAY_SINGULAR|PATH_RAY_MIS_SKIP);
        }
        else if(label & LABEL_GLOSSY) {
                state->flag |= PATH_RAY_GLOSSY;
-               state->flag &= ~(PATH_RAY_DIFFUSE|PATH_RAY_SINGULAR);
+               state->flag &= ~(PATH_RAY_DIFFUSE|PATH_RAY_SINGULAR|PATH_RAY_MIS_SKIP);
        }
        else {
                kernel_assert(label & LABEL_SINGULAR);
 
-               state->flag |= PATH_RAY_GLOSSY|PATH_RAY_SINGULAR;
+               state->flag |= PATH_RAY_GLOSSY|PATH_RAY_SINGULAR|PATH_RAY_MIS_SKIP;
                state->flag &= ~PATH_RAY_DIFFUSE;
        }
 }
@@ -167,7 +170,7 @@ __device_inline bool shadow_blocked(KernelGlobals *kg, PathState *state, Ray *ra
        if(ray->t == 0.0f)
                return false;
        
-       bool result = scene_intersect(kg, ray, PATH_RAY_SHADOW, isect);
+       bool result = scene_intersect(kg, ray, PATH_RAY_SHADOW_OPAQUE, isect);
 
 #ifdef __TRANSPARENT_SHADOWS__
        if(result && kernel_data.integrator.transparent_shadows) {
@@ -175,11 +178,11 @@ __device_inline bool shadow_blocked(KernelGlobals *kg, PathState *state, Ray *ra
                   in cases where we don't need them. after a regular shadow ray is
                   cast we check if the hit primitive was potentially transparent, and
                   only in that case start marching. this gives on extra ray cast for
-                  the cases were we do want transparency */
+                  the cases were we do want transparency.
+                  
+                  also note that for this to work correct, multi close sampling must
+                  be used, since we don't pass a random number to shader_eval_surface */
                if(shader_transparent_shadow(kg, isect)) {
-                       /* todo: fix double contribution from indirect for triangle lights */
-                       /* if(kernel_data.integrator.transparent_shadows && (path_flag & PATH_RAY_TRANSPARENT)) */
-
                        float3 throughput = make_float3(1.0f, 1.0f, 1.0f);
                        float3 Pend = ray->P + ray->D*ray->t;
                        int bounce = state->transparent_bounce;
@@ -192,7 +195,7 @@ __device_inline bool shadow_blocked(KernelGlobals *kg, PathState *state, Ray *ra
                                        /* todo: get random number somewhere for probabilistic terminate */
 #if 0
                                        float probability = average(throughput);
-                                       float terminate = 0.0f; /* todo: get this random number */
+                                       float terminate = 0.0f;
 
                                        if(terminate >= probability)
                                                return true;
@@ -201,22 +204,23 @@ __device_inline bool shadow_blocked(KernelGlobals *kg, PathState *state, Ray *ra
 #endif
                                }
 
-                               /* todo: fix it so we get first hit */
-                               if(!scene_intersect(kg, ray, PATH_RAY_SHADOW, isect)) {
+                               if(!scene_intersect(kg, ray, PATH_RAY_SHADOW_TRANSPARENT, isect)) {
                                        *light_L *= throughput;
                                        return false;
                                }
+
                                if(!shader_transparent_shadow(kg, isect))
                                        return true;
 
                                ShaderData sd;
                                shader_setup_from_ray(kg, &sd, isect, ray);
-                               shader_eval_surface(kg, &sd, 0.0f, PATH_RAY_SHADOW); /* todo: state flag? */
+                               shader_eval_surface(kg, &sd, 0.0f, PATH_RAY_SHADOW);
 
                                throughput *= shader_bsdf_transparency(kg, &sd);
 
                                ray->P = ray_offset(sd.P, -sd.Ng);
-                               ray->t = (ray->t == FLT_MAX)? FLT_MAX: len(Pend - ray->P);
+                               if(ray->t != FLT_MAX)
+                                       ray->D = normalize_len(Pend - ray->P, &ray->t);
 
                                bounce++;
                        }
@@ -360,7 +364,7 @@ __device float4 kernel_path_integrate(KernelGlobals *kg, RNG *rng, int sample, R
 #endif
 
                /* update path state */
-               path_state_next(&state, label);
+               path_state_next(kg, &state, label);
 
                /* setup ray */
                ray.P = ray_offset(sd.P, (label & LABEL_TRANSMIT)? -sd.Ng: sd.Ng);