From cbd881da3fd2a68272988cf7fd21dfe006d47c8c Mon Sep 17 00:00:00 2001
From: Kenneth Graunke <kenneth@whitecape.org>
Date: Wed, 9 Jun 2010 14:30:52 -0700
Subject: [PATCH] Implement 'refract' builtin.

---
 builtin_function.cpp | 106 +++++++++++++++++++++++++++++++++++++++++++
 builtins/110/refract | 102 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 208 insertions(+)
 create mode 100644 builtins/110/refract

diff --git a/builtin_function.cpp b/builtin_function.cpp
index c75805c782a..377fd509551 100644
--- a/builtin_function.cpp
+++ b/builtin_function.cpp
@@ -1718,6 +1718,111 @@ static const char *builtins_110_reflect = {
    "))\n"
 };
 
+static const char *builtins_110_refract = {
+   "((function refract\n"
+   "   (signature float\n"
+   "     (parameters\n"
+   "       (declare (in) float i)\n"
+   "       (declare (in) float n)\n"
+   "       (declare (in) float eta))\n"
+   "     ((declare () float k)\n"
+   "      (assign (constant bool (1)) (var_ref k)\n"
+   "              (expression float - (constant float (1.0))\n"
+   "	        (expression float * (var_ref eta)\n"
+   "	          (expression float * (var_ref eta)\n"
+   "		    (expression float - (constant float (1.0))\n"
+   "		      (expression float * \n"
+   "		        (expression float dot (var_ref n) (var_ref i))\n"
+   "		        (expression float dot (var_ref n) (var_ref i))))))))\n"
+   "      (if (expression bool < (var_ref k) (constant float (0.0)))\n"
+   "          ((return (constant float (0.0))))\n"
+   "	  ((return (expression float -\n"
+   "	             (expression float * (var_ref eta) (var_ref i))\n"
+   "		     (expression float *\n"
+   "		       (expression float +\n"
+   "		         (expression float * (var_ref eta)\n"
+   "			   (expression float dot (var_ref n) (var_ref i)))\n"
+   "		         (expression float sqrt (var_ref k)))\n"
+   "		       (var_ref n))))))))\n"
+   "\n"
+   "   (signature vec2\n"
+   "     (parameters\n"
+   "       (declare (in) vec2 i)\n"
+   "       (declare (in) vec2 n)\n"
+   "       (declare (in) float eta))\n"
+   "     ((declare () float k)\n"
+   "      (assign (constant bool (1)) (var_ref k)\n"
+   "              (expression float - (constant float (1.0))\n"
+   "	        (expression float * (var_ref eta)\n"
+   "	          (expression float * (var_ref eta)\n"
+   "		    (expression float - (constant float (1.0))\n"
+   "		      (expression float * \n"
+   "		        (expression float dot (var_ref n) (var_ref i))\n"
+   "		        (expression float dot (var_ref n) (var_ref i))))))))\n"
+   "      (if (expression bool < (var_ref k) (constant float (0.0)))\n"
+   "          ((return (constant vec2 (0.0 0.0))))\n"
+   "	  ((return (expression vec2 -\n"
+   "	             (expression vec2 * (var_ref eta) (var_ref i))\n"
+   "		     (expression vec2 *\n"
+   "		       (expression float +\n"
+   "		         (expression float * (var_ref eta)\n"
+   "			   (expression float dot (var_ref n) (var_ref i)))\n"
+   "		         (expression float sqrt (var_ref k)))\n"
+   "		       (var_ref n))))))))\n"
+   "\n"
+   "   (signature vec3\n"
+   "     (parameters\n"
+   "       (declare (in) vec3 i)\n"
+   "       (declare (in) vec3 n)\n"
+   "       (declare (in) float eta))\n"
+   "     ((declare () float k)\n"
+   "      (assign (constant bool (1)) (var_ref k)\n"
+   "              (expression float - (constant float (1.0))\n"
+   "	        (expression float * (var_ref eta)\n"
+   "	          (expression float * (var_ref eta)\n"
+   "		    (expression float - (constant float (1.0))\n"
+   "		      (expression float * \n"
+   "		        (expression float dot (var_ref n) (var_ref i))\n"
+   "		        (expression float dot (var_ref n) (var_ref i))))))))\n"
+   "      (if (expression bool < (var_ref k) (constant float (0.0)))\n"
+   "          ((return (constant vec3 (0.0 0.0))))\n"
+   "	  ((return (expression vec3 -\n"
+   "	             (expression vec3 * (var_ref eta) (var_ref i))\n"
+   "		     (expression vec3 *\n"
+   "		       (expression float +\n"
+   "		         (expression float * (var_ref eta)\n"
+   "			   (expression float dot (var_ref n) (var_ref i)))\n"
+   "		         (expression float sqrt (var_ref k)))\n"
+   "		       (var_ref n))))))))\n"
+   "\n"
+   "   (signature vec4\n"
+   "     (parameters\n"
+   "       (declare (in) vec4 i)\n"
+   "       (declare (in) vec4 n)\n"
+   "       (declare (in) float eta))\n"
+   "     ((declare () float k)\n"
+   "      (assign (constant bool (1)) (var_ref k)\n"
+   "              (expression float - (constant float (1.0))\n"
+   "	        (expression float * (var_ref eta)\n"
+   "	          (expression float * (var_ref eta)\n"
+   "		    (expression float - (constant float (1.0))\n"
+   "		      (expression float * \n"
+   "		        (expression float dot (var_ref n) (var_ref i))\n"
+   "		        (expression float dot (var_ref n) (var_ref i))))))))\n"
+   "      (if (expression bool < (var_ref k) (constant float (0.0)))\n"
+   "          ((return (constant vec4 (0.0 0.0))))\n"
+   "	  ((return (expression vec4 -\n"
+   "	             (expression vec4 * (var_ref eta) (var_ref i))\n"
+   "		     (expression vec4 *\n"
+   "		       (expression float +\n"
+   "		         (expression float * (var_ref eta)\n"
+   "			   (expression float dot (var_ref n) (var_ref i)))\n"
+   "		         (expression float sqrt (var_ref k)))\n"
+   "		       (var_ref n))))))))\n"
+   "\n"
+   "))\n"
+};
+
 static const char *builtins_110_sign = {
    "((function sign\n"
    "   (signature float\n"
@@ -2379,6 +2484,7 @@ static const char *functions_for_110 [] = {
    builtins_110_pow,
    builtins_110_radians,
    builtins_110_reflect,
+   builtins_110_refract,
    builtins_110_sign,
    builtins_110_sin,
    builtins_110_smoothstep,
diff --git a/builtins/110/refract b/builtins/110/refract
new file mode 100644
index 00000000000..e9b1475294a
--- /dev/null
+++ b/builtins/110/refract
@@ -0,0 +1,102 @@
+((function refract
+   (signature float
+     (parameters
+       (declare (in) float i)
+       (declare (in) float n)
+       (declare (in) float eta))
+     ((declare () float k)
+      (assign (constant bool (1)) (var_ref k)
+              (expression float - (constant float (1.0))
+	        (expression float * (var_ref eta)
+	          (expression float * (var_ref eta)
+		    (expression float - (constant float (1.0))
+		      (expression float * 
+		        (expression float dot (var_ref n) (var_ref i))
+		        (expression float dot (var_ref n) (var_ref i))))))))
+      (if (expression bool < (var_ref k) (constant float (0.0)))
+          ((return (constant float (0.0))))
+	  ((return (expression float -
+	             (expression float * (var_ref eta) (var_ref i))
+		     (expression float *
+		       (expression float +
+		         (expression float * (var_ref eta)
+			   (expression float dot (var_ref n) (var_ref i)))
+		         (expression float sqrt (var_ref k)))
+		       (var_ref n))))))))
+
+   (signature vec2
+     (parameters
+       (declare (in) vec2 i)
+       (declare (in) vec2 n)
+       (declare (in) float eta))
+     ((declare () float k)
+      (assign (constant bool (1)) (var_ref k)
+              (expression float - (constant float (1.0))
+	        (expression float * (var_ref eta)
+	          (expression float * (var_ref eta)
+		    (expression float - (constant float (1.0))
+		      (expression float * 
+		        (expression float dot (var_ref n) (var_ref i))
+		        (expression float dot (var_ref n) (var_ref i))))))))
+      (if (expression bool < (var_ref k) (constant float (0.0)))
+          ((return (constant vec2 (0.0 0.0))))
+	  ((return (expression vec2 -
+	             (expression vec2 * (var_ref eta) (var_ref i))
+		     (expression vec2 *
+		       (expression float +
+		         (expression float * (var_ref eta)
+			   (expression float dot (var_ref n) (var_ref i)))
+		         (expression float sqrt (var_ref k)))
+		       (var_ref n))))))))
+
+   (signature vec3
+     (parameters
+       (declare (in) vec3 i)
+       (declare (in) vec3 n)
+       (declare (in) float eta))
+     ((declare () float k)
+      (assign (constant bool (1)) (var_ref k)
+              (expression float - (constant float (1.0))
+	        (expression float * (var_ref eta)
+	          (expression float * (var_ref eta)
+		    (expression float - (constant float (1.0))
+		      (expression float * 
+		        (expression float dot (var_ref n) (var_ref i))
+		        (expression float dot (var_ref n) (var_ref i))))))))
+      (if (expression bool < (var_ref k) (constant float (0.0)))
+          ((return (constant vec3 (0.0 0.0))))
+	  ((return (expression vec3 -
+	             (expression vec3 * (var_ref eta) (var_ref i))
+		     (expression vec3 *
+		       (expression float +
+		         (expression float * (var_ref eta)
+			   (expression float dot (var_ref n) (var_ref i)))
+		         (expression float sqrt (var_ref k)))
+		       (var_ref n))))))))
+
+   (signature vec4
+     (parameters
+       (declare (in) vec4 i)
+       (declare (in) vec4 n)
+       (declare (in) float eta))
+     ((declare () float k)
+      (assign (constant bool (1)) (var_ref k)
+              (expression float - (constant float (1.0))
+	        (expression float * (var_ref eta)
+	          (expression float * (var_ref eta)
+		    (expression float - (constant float (1.0))
+		      (expression float * 
+		        (expression float dot (var_ref n) (var_ref i))
+		        (expression float dot (var_ref n) (var_ref i))))))))
+      (if (expression bool < (var_ref k) (constant float (0.0)))
+          ((return (constant vec4 (0.0 0.0))))
+	  ((return (expression vec4 -
+	             (expression vec4 * (var_ref eta) (var_ref i))
+		     (expression vec4 *
+		       (expression float +
+		         (expression float * (var_ref eta)
+			   (expression float dot (var_ref n) (var_ref i)))
+		         (expression float sqrt (var_ref k)))
+		       (var_ref n))))))))
+
+))
-- 
2.30.2