Implement sky spheres.

7 files changed, 63 insertions, 1 deletions

diff --git a/dimension/common.terminals b/dimension/common.terminals
index 5a0d778..4e8e6d1 100644
--- a/dimension/common.terminals
+++ b/dimension/common.terminals
@@ -394,7 +394,7 @@
 %token DMNSN_T_SINH                     "sinh"
 %token DMNSN_T_SIZE
 %token DMNSN_T_SKY                      "sky"
-%token DMNSN_T_SKY_SPHERE
+%token DMNSN_T_SKY_SPHERE               "sky_sphere"
 %token DMNSN_T_SLICE
 %token DMNSN_T_SLOPE
 %token DMNSN_T_SLOPE_MAP
diff --git a/dimension/grammar.epilogue b/dimension/grammar.epilogue
index 0eace5e..77a782a 100644
--- a/dimension/grammar.epilogue
+++ b/dimension/grammar.epilogue
@@ -126,6 +126,7 @@ dmnsn_astnode_string(dmnsn_astnode_type astnode_type)
   dmnsn_astnode_map(DMNSN_AST_MAX_TRACE_LEVEL,   "max_trace_level");
 
   dmnsn_astnode_map(DMNSN_AST_BACKGROUND, "background");
+  dmnsn_astnode_map(DMNSN_AST_SKY_SPHERE, "sky_sphere");
 
   dmnsn_astnode_map(DMNSN_AST_CAMERA,      "camera");
   dmnsn_astnode_map(DMNSN_AST_PERSPECTIVE, "perspective");
diff --git a/dimension/grammar.nonterminals b/dimension/grammar.nonterminals
index 9ab8ee1..912b660 100644
--- a/dimension/grammar.nonterminals
+++ b/dimension/grammar.nonterminals
@@ -31,3 +31,5 @@
 /* Atmospheric effects */
 %type <astnode> ATMOSPHERIC_EFFECT
 %type <astnode> BACKGROUND
+%type <astnode> SKY_SPHERE
+%type <astnode> SKY_SPHERE_ITEMS
diff --git a/dimension/grammar.rules b/dimension/grammar.rules
index 0e9d6f1..8b110c0 100644
--- a/dimension/grammar.rules
+++ b/dimension/grammar.rules
@@ -94,9 +94,31 @@ GLOBAL_CHARSET: "ascii" {
 /* Atmospheric effects */
 
 ATMOSPHERIC_EFFECT: BACKGROUND
+                  | SKY_SPHERE
 ;
 
 BACKGROUND: "background" "{" COLOR "}" {
             $$ = dmnsn_new_astnode1(DMNSN_AST_BACKGROUND, @$, $3);
           }
 ;
+
+SKY_SPHERE: "sky_sphere" "{"
+              SKY_SPHERE_ITEMS
+            "}"
+          {
+            $$ = $3;
+          }
+;
+
+SKY_SPHERE_ITEMS: /* empty */ {
+                  $$ = dmnsn_new_astnode(DMNSN_AST_SKY_SPHERE, @$);
+                }
+                | SKY_SPHERE_ITEMS PIGMENT {
+                  $$ = $1;
+                  dmnsn_array_push($$.children, &$2);
+                }
+                | SKY_SPHERE_ITEMS TRANSFORMATION {
+                  $$ = $1;
+                  dmnsn_array_push($$.children, &$2);
+                }
+;
diff --git a/dimension/lexer.l b/dimension/lexer.l
index 5e1afa2..c5eeca7 100644
--- a/dimension/lexer.l
+++ b/dimension/lexer.l
@@ -258,6 +258,7 @@ unsigned long wchar;
 "sin"                   RETURN_TOKEN(DMNSN_T_SIN);
 "sinh"                  RETURN_TOKEN(DMNSN_T_SINH);
 "sky"                   RETURN_TOKEN(DMNSN_T_SKY);
+"sky_sphere"            RETURN_TOKEN(DMNSN_T_SKY_SPHERE);
 "sphere"                RETURN_TOKEN(DMNSN_T_SPHERE);
 "sqrt"                  RETURN_TOKEN(DMNSN_T_SQRT);
 "strcmp"                RETURN_TOKEN(DMNSN_T_STRCMP);
diff --git a/dimension/parse.h b/dimension/parse.h
index 38e4eef..7bff5ba 100644
--- a/dimension/parse.h
+++ b/dimension/parse.h
@@ -40,6 +40,7 @@ typedef enum {
   DMNSN_AST_MAX_INTERSECTIONS,
 
   DMNSN_AST_BACKGROUND,
+  DMNSN_AST_SKY_SPHERE,
 
   DMNSN_AST_CAMERA,
   DMNSN_AST_PERSPECTIVE,
diff --git a/dimension/realize.c b/dimension/realize.c
index d4b45cb..2f74ce0 100644
--- a/dimension/realize.c
+++ b/dimension/realize.c
@@ -680,6 +680,37 @@ dmnsn_realize_pigment(dmnsn_astnode astnode)
   return pigment;
 }
 
+static dmnsn_sky_sphere *
+dmnsn_realize_sky_sphere(dmnsn_astnode astnode)
+{
+  dmnsn_assert(astnode.type == DMNSN_AST_SKY_SPHERE, "Expected a sky sphere.");
+
+  dmnsn_sky_sphere *sky_sphere = dmnsn_new_sky_sphere();
+
+  DMNSN_ARRAY_FOREACH (dmnsn_astnode *, item, astnode.children) {
+    switch (item->type) {
+    case DMNSN_AST_PIGMENT:
+      {
+        dmnsn_pigment *pigment = dmnsn_realize_pigment(*item);
+        dmnsn_array_push(sky_sphere->pigments, &pigment);
+        break;
+      }
+
+    case DMNSN_AST_TRANSFORMATION:
+      sky_sphere->trans = dmnsn_matrix_mul(
+        dmnsn_realize_transformation(*item),
+        sky_sphere->trans
+      );
+      break;
+
+    default:
+      dmnsn_assert(false, "Invalid sky sphere item.");
+    }
+  }
+
+  return sky_sphere;
+}
+
 static dmnsn_finish *
 dmnsn_realize_reflection(dmnsn_astnode astnode)
 {
@@ -1295,6 +1326,10 @@ dmnsn_realize_astree(const dmnsn_astree *astree)
       dmnsn_array_get(astnode->children, 0, &child);
       scene->background = dmnsn_realize_color(child);
       break;
+    case DMNSN_AST_SKY_SPHERE:
+      dmnsn_delete_sky_sphere(scene->sky_sphere);
+      scene->sky_sphere = dmnsn_realize_sky_sphere(*astnode);
+      break;
 
     case DMNSN_AST_CAMERA:
       dmnsn_delete_camera(scene->camera);