From 6137aed0179476eaa626660885f01ea3f04f988a Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@gmail.com>
Date: Fri, 19 Nov 2010 14:30:41 -0500
Subject: Support global ambient_light.

---
 dimension/common.terminals     | 2 +-
 dimension/grammar.declarations | 2 +-
 dimension/grammar.rules        | 5 ++++-
 dimension/lexer.l              | 1 +
 dimension/realize.c            | 7 +++++++
 libdimension/dimension/scene.h | 1 +
 libdimension/raytrace.c        | 4 +++-
 libdimension/scene.c           | 2 ++
 8 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/dimension/common.terminals b/dimension/common.terminals
index 079aede..5a0d778 100644
--- a/dimension/common.terminals
+++ b/dimension/common.terminals
@@ -80,7 +80,7 @@
 %token DMNSN_T_ALTITUDE
 %token DMNSN_T_ALWAYS_SAMPLE
 %token DMNSN_T_AMBIENT                  "ambient"
-%token DMNSN_T_AMBIENT_LIGHT
+%token DMNSN_T_AMBIENT_LIGHT            "ambient_light"
 %token DMNSN_T_ANGLE                    "angle"
 %token DMNSN_T_APERTURE
 %token DMNSN_T_APPEND
diff --git a/dimension/grammar.declarations b/dimension/grammar.declarations
index 58b995f..ef3f7a2 100644
--- a/dimension/grammar.declarations
+++ b/dimension/grammar.declarations
@@ -23,7 +23,7 @@
 
 %name-prefix "dmnsn_yy"
 
-%expect 12
+%expect 13
 
 %parse-param {const char *filename}
 %parse-param {void *yyscanner}
diff --git a/dimension/grammar.rules b/dimension/grammar.rules
index 1ce3e1f..0e9d6f1 100644
--- a/dimension/grammar.rules
+++ b/dimension/grammar.rules
@@ -55,7 +55,10 @@ GLOBAL_SETTINGS_ITEMS: /* empty */ {
                      }
 ;
 
-GLOBAL_SETTINGS_ITEM: "assumed_gamma" FLOAT {
+GLOBAL_SETTINGS_ITEM: "ambient_light" COLOR {
+                      $$ = dmnsn_new_astnode1(DMNSN_AST_AMBIENT, @$, $2);
+                    }
+                    | "assumed_gamma" FLOAT {
                       dmnsn_diagnostic(@1,
                                        "WARNING: assumed_gamma not supported");
                       $$ = dmnsn_new_astnode1(DMNSN_AST_ASSUMED_GAMMA, @$, $2);
diff --git a/dimension/lexer.l b/dimension/lexer.l
index 8216091..5e1afa2 100644
--- a/dimension/lexer.l
+++ b/dimension/lexer.l
@@ -169,6 +169,7 @@ unsigned long wchar;
 "acos"                  RETURN_TOKEN(DMNSN_T_ACOS);
 "acosh"                 RETURN_TOKEN(DMNSN_T_ACOSH);
 "ambient"               RETURN_TOKEN(DMNSN_T_AMBIENT);
+"ambient_light"         RETURN_TOKEN(DMNSN_T_AMBIENT_LIGHT);
 "angle"                 RETURN_TOKEN(DMNSN_T_ANGLE);
 "asc"                   RETURN_TOKEN(DMNSN_T_ASC);
 "ascii"                 RETURN_TOKEN(DMNSN_T_ASCII);
diff --git a/dimension/realize.c b/dimension/realize.c
index 15d4104..d4b45cb 100644
--- a/dimension/realize.c
+++ b/dimension/realize.c
@@ -239,6 +239,13 @@ dmnsn_realize_global_settings(dmnsn_astnode astnode, dmnsn_scene *scene)
     dmnsn_astnode child;
 
     switch (item->type) {
+    case DMNSN_AST_AMBIENT:
+      dmnsn_array_get(item->children, 0, &child);
+      scene->ambient = dmnsn_realize_color(child);
+      scene->ambient.filter = 0.0;
+      scene->ambient.trans  = 0.0;
+      break;
+
     case DMNSN_AST_MAX_TRACE_LEVEL:
       dmnsn_array_get(item->children, 0, &child);
       scene->reclimit = dmnsn_realize_integer(child);
diff --git a/libdimension/dimension/scene.h b/libdimension/dimension/scene.h
index 57ef32b..489e4e5 100644
--- a/libdimension/dimension/scene.h
+++ b/libdimension/dimension/scene.h
@@ -44,6 +44,7 @@ typedef unsigned int dmnsn_quality;
 typedef struct dmnsn_scene {
   /* World attributes */
   dmnsn_color background;         /**< Background color. */
+  dmnsn_color ambient;            /**< Global ambient color. */
   dmnsn_texture *default_texture; /**< Default object texture. */
 
   /** Camera. */
diff --git a/libdimension/raytrace.c b/libdimension/raytrace.c
index 74f4557..e6596e4 100644
--- a/libdimension/raytrace.c
+++ b/libdimension/raytrace.c
@@ -337,9 +337,11 @@ dmnsn_raytrace_light_ray(const dmnsn_raytrace_state *state,
 static void
 dmnsn_raytrace_lighting(dmnsn_raytrace_state *state)
 {
-  /* The illuminated color */
+  /* The ambient color */
   state->diffuse = TEXTURE_CALLBACK(state, finish, ambient_fn, dmnsn_black,
                                     state->pigment);
+  state->diffuse = dmnsn_color_illuminate(state->scene->ambient,
+                                          state->diffuse);
 
   if (!TEXTURE_HAS_CALLBACK(state, finish, diffuse_fn)
       && !TEXTURE_HAS_CALLBACK(state, finish, specular_fn))
diff --git a/libdimension/scene.c b/libdimension/scene.c
index fc5bb92..9eca7b7 100644
--- a/libdimension/scene.c
+++ b/libdimension/scene.c
@@ -32,6 +32,8 @@ dmnsn_new_scene()
 {
   dmnsn_scene *scene = dmnsn_malloc(sizeof(dmnsn_scene));
 
+  scene->background      = dmnsn_black;
+  scene->ambient         = dmnsn_white;
   scene->default_texture = dmnsn_new_texture();
   scene->camera          = NULL;
   scene->canvas          = NULL;
-- 
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