Implement adaptive depth control.

11 files changed, 48 insertions, 7 deletions

diff --git a/dimension/common.terminals b/dimension/common.terminals
index f96a1f6..567267b 100644
--- a/dimension/common.terminals
+++ b/dimension/common.terminals
@@ -71,7 +71,7 @@
 %token DMNSN_T_ACOS                     "acos"
 %token DMNSN_T_ACOSH                    "acosh"
 %token DMNSN_T_ADAPTIVE
-%token DMNSN_T_ADC_BAILOUT
+%token DMNSN_T_ADC_BAILOUT              "adc_bailout"
 %token DMNSN_T_AGATE
 %token DMNSN_T_AGATE_TURB
 %token DMNSN_T_ALL
diff --git a/dimension/grammar.epilogue b/dimension/grammar.epilogue
index ffa93bf..9b2fa29 100644
--- a/dimension/grammar.epilogue
+++ b/dimension/grammar.epilogue
@@ -117,6 +117,7 @@ dmnsn_astnode_string(dmnsn_astnode_type astnode_type)
   dmnsn_astnode_map(DMNSN_AST_NONE, "none");
 
   dmnsn_astnode_map(DMNSN_AST_GLOBAL_SETTINGS,   "global_settings");
+  dmnsn_astnode_map(DMNSN_AST_ADC_BAILOUT,       "adc_bailout");
   dmnsn_astnode_map(DMNSN_AST_ASSUMED_GAMMA,     "assumed_gamma");
   dmnsn_astnode_map(DMNSN_AST_CHARSET,           "charset");
   dmnsn_astnode_map(DMNSN_AST_ASCII,             "ascii");
diff --git a/dimension/grammar.rules b/dimension/grammar.rules
index 5f08e20..148e082 100644
--- a/dimension/grammar.rules
+++ b/dimension/grammar.rules
@@ -55,7 +55,10 @@ GLOBAL_SETTINGS_ITEMS: /* empty */ {
                      }
 ;
 
-GLOBAL_SETTINGS_ITEM: "ambient_light" COLOR {
+GLOBAL_SETTINGS_ITEM: "adc_bailout" FLOAT {
+                      $$ = dmnsn_new_astnode1(DMNSN_AST_ADC_BAILOUT, @$, $2);
+                    }
+                    | "ambient_light" COLOR {
                       $$ = dmnsn_new_astnode1(DMNSN_AST_AMBIENT, @$, $2);
                     }
                     | "assumed_gamma" FLOAT {
diff --git a/dimension/lexer.l b/dimension/lexer.l
index dbafec2..89cc0a7 100644
--- a/dimension/lexer.l
+++ b/dimension/lexer.l
@@ -168,6 +168,7 @@ unsigned int wchar;
 "abs"                   RETURN_TOKEN(DMNSN_T_ABS);
 "acos"                  RETURN_TOKEN(DMNSN_T_ACOS);
 "acosh"                 RETURN_TOKEN(DMNSN_T_ACOSH);
+"adc_bailout"           RETURN_TOKEN(DMNSN_T_ADC_BAILOUT);
 "ambient"               RETURN_TOKEN(DMNSN_T_AMBIENT);
 "ambient_light"         RETURN_TOKEN(DMNSN_T_AMBIENT_LIGHT);
 "angle"                 RETURN_TOKEN(DMNSN_T_ANGLE);
diff --git a/dimension/parse.h b/dimension/parse.h
index 4471edf..a357324 100644
--- a/dimension/parse.h
+++ b/dimension/parse.h
@@ -31,6 +31,7 @@ typedef enum {
   DMNSN_AST_NONE,
 
   DMNSN_AST_GLOBAL_SETTINGS,
+  DMNSN_AST_ADC_BAILOUT,
   DMNSN_AST_ASSUMED_GAMMA,
   DMNSN_AST_CHARSET,
   DMNSN_AST_ASCII,
diff --git a/dimension/realize.c b/dimension/realize.c
index 2603ba1..c9a507d 100644
--- a/dimension/realize.c
+++ b/dimension/realize.c
@@ -232,6 +232,11 @@ dmnsn_realize_global_settings(dmnsn_astnode astnode, dmnsn_scene *scene)
     dmnsn_astnode child;
 
     switch (item->type) {
+    case DMNSN_AST_ADC_BAILOUT:
+      dmnsn_array_get(item->children, 0, &child);
+      scene->adc_bailout = dmnsn_realize_float(child);
+      break;
+
     case DMNSN_AST_AMBIENT:
       dmnsn_array_get(item->children, 0, &child);
       scene->ambient = dmnsn_realize_color(child);
diff --git a/libdimension/dimension/scene.h b/libdimension/dimension/scene.h
index 747c764..7b44231 100644
--- a/libdimension/dimension/scene.h
+++ b/libdimension/dimension/scene.h
@@ -66,6 +66,9 @@ typedef struct dmnsn_scene {
   /** Recursion limit. */
   unsigned int reclimit;
 
+  /** Adaptive depth control bailout. */
+  double adc_bailout;
+
   /** Number of parallel threads. */
   unsigned int nthreads;
 
diff --git a/libdimension/raytrace.c b/libdimension/raytrace.c
index a35b1e6..f5c68e6 100644
--- a/libdimension/raytrace.c
+++ b/libdimension/raytrace.c
@@ -109,7 +109,7 @@ typedef struct dmnsn_raytrace_state {
 
   const dmnsn_scene *scene;
   const dmnsn_intersection *intersection;
-  dmnsn_prtree *prtree;
+  const dmnsn_prtree *prtree;
   unsigned int reclevel;
 
   dmnsn_vector r;
@@ -121,6 +121,8 @@ typedef struct dmnsn_raytrace_state {
   dmnsn_color additional;
 
   double ior;
+
+  dmnsn_color adc_value;
 } dmnsn_raytrace_state;
 
 /** Main helper for dmnsn_raytrace_scene_impl - shoot a ray. */
@@ -156,6 +158,7 @@ dmnsn_raytrace_scene_concurrent(void *ptr, unsigned int thread,
       /* Shoot a ray */
       state.reclevel = scene->reclimit;
       state.ior = 1.0;
+      state.adc_value = dmnsn_white;
       dmnsn_color color = dmnsn_raytrace_shoot(&state, ray);
 
       dmnsn_set_pixel(scene->canvas, x, y, color);
@@ -253,7 +256,9 @@ dmnsn_raytrace_light_ray(const dmnsn_raytrace_state *state,
   dmnsn_color color = light->light_fn(light, state->r);
 
   unsigned int reclevel = state->reclevel;
-  while (reclevel > 0) {
+  while (reclevel > 0
+         && dmnsn_color_intensity(color) >= state->scene->adc_bailout)
+  {
     dmnsn_intersection shadow_caster;
     bool shadow_casted = dmnsn_prtree_intersection(state->prtree, shadow_ray,
                                                    &shadow_caster, false);
@@ -268,7 +273,8 @@ dmnsn_raytrace_light_ray(const dmnsn_raytrace_state *state,
 
     dmnsn_raytrace_pigment(&shadow_state);
     if ((state->scene->quality & DMNSN_RENDER_TRANSLUCENCY)
-        && (shadow_state.pigment.filter || shadow_state.pigment.trans)) {
+        && (shadow_state.pigment.filter || shadow_state.pigment.trans))
+    {
       color = dmnsn_filter_light(color, shadow_state.pigment);
       shadow_ray.x0 = dmnsn_line_point(shadow_ray, shadow_caster.t);
       shadow_ray.n  = dmnsn_vector_sub(light->x0, shadow_ray.x0);
@@ -339,6 +345,11 @@ dmnsn_raytrace_reflection(const dmnsn_raytrace_state *state)
     refl_ray = dmnsn_line_add_epsilon(refl_ray);
 
     dmnsn_raytrace_state recursive_state = *state;
+    recursive_state.adc_value = TEXTURE_CALLBACK(
+      state, finish, reflection_fn, dmnsn_black,
+      state->adc_value, state->pigment, state->reflected,
+      state->intersection->normal
+    );
     dmnsn_color rec = dmnsn_raytrace_shoot(&recursive_state, refl_ray);
     reflected = TEXTURE_CALLBACK(
       state, finish, reflection_fn, dmnsn_black,
@@ -396,6 +407,9 @@ dmnsn_raytrace_translucency(dmnsn_raytrace_state *state)
       );
     }
 
+    recursive_state.adc_value
+      = dmnsn_filter_light(state->adc_value, state->pigment);
+
     dmnsn_color rec = dmnsn_raytrace_shoot(&recursive_state, trans_ray);
     dmnsn_color filtered = dmnsn_filter_light(rec, state->pigment);
     state->diffuse.filter = state->pigment.filter;
@@ -408,8 +422,12 @@ dmnsn_raytrace_translucency(dmnsn_raytrace_state *state)
 static dmnsn_color
 dmnsn_raytrace_shoot(dmnsn_raytrace_state *state, dmnsn_line ray)
 {
-  if (state->reclevel == 0)
+  if (state->reclevel == 0
+      || dmnsn_color_intensity(state->adc_value) < state->scene->adc_bailout)
+  {
     return dmnsn_black;
+  }
+
   --state->reclevel;
 
   /* Calculate the background color */
diff --git a/libdimension/scene.c b/libdimension/scene.c
index 95c8f32..fadd077 100644
--- a/libdimension/scene.c
+++ b/libdimension/scene.c
@@ -42,6 +42,7 @@ dmnsn_new_scene(void)
   scene->lights          = dmnsn_new_array(sizeof(dmnsn_light *));
   scene->quality         = DMNSN_RENDER_FULL;
   scene->reclimit        = 5;
+  scene->adc_bailout     = 1.0/255.0;
   scene->nthreads        = dmnsn_ncpus();
   scene->bounding_timer  = NULL;
   scene->render_timer    = NULL;
diff --git a/tests/dimension/demo.pov b/tests/dimension/demo.pov
index 390c4c6..91be9d2 100644
--- a/tests/dimension/demo.pov
+++ b/tests/dimension/demo.pov
@@ -19,6 +19,11 @@
 
 // Render demo scene
 
+global_settings {
+  max_trace_level 5
+  adc_bailout 1/255
+}
+
 camera {
   perspective
   location <0, 0.25, -4>
diff --git a/tests/dimension/demo.sh b/tests/dimension/demo.sh
index 10cf13b..233b880 100755
--- a/tests/dimension/demo.sh
+++ b/tests/dimension/demo.sh
@@ -21,7 +21,10 @@
 
 demo=$(${top_builddir}/dimension/dimension ${dimension_flags} -w768 -h480 --parse ${srcdir}/demo.pov)
 demo_exp=$(echo -n \
-'((camera
+'((global_settings
+    (max_trace_level (integer 5))
+    (adc_bailout (float 0.00392157)))
+  (camera
     perspective
     (location (vector (integer 0) (float 0.25) (integer -4)
                       (integer 0) (integer 0)))