Implement dFdx, dFdy, and fwidth via new expression opcodes.

1 files changed, 73 insertions, 0 deletions

diff --git a/builtins/110_fs/derivatives b/builtins/110_fs/derivatives
new file mode 100644
index 00000000000..b79852ee1ff
--- /dev/null
+++ b/builtins/110_fs/derivatives
@@ -0,0 +1,73 @@
+((function dFdx
+   (signature float
+     (parameters
+       (declare (in) float p))
+     ((return (expression float dFdx (var_ref p)))))
+
+   (signature vec2
+     (parameters
+       (declare (in) vec2 p))
+     ((return (expression vec2 dFdx (var_ref p)))))
+
+   (signature vec3
+     (parameters
+       (declare (in) vec3 p))
+     ((return (expression vec3 dFdx (var_ref p)))))
+
+   (signature vec4
+     (parameters
+       (declare (in) vec4 p))
+     ((return (expression vec4 dFdx (var_ref p)))))
+ )
+
+ (function dFdy
+   (signature float
+     (parameters
+       (declare (in) float p))
+     ((return (expression float dFdy (var_ref p)))))
+
+   (signature vec2
+     (parameters
+       (declare (in) vec2 p))
+     ((return (expression vec2 dFdy (var_ref p)))))
+
+   (signature vec3
+     (parameters
+       (declare (in) vec3 p))
+     ((return (expression vec3 dFdy (var_ref p)))))
+
+   (signature vec4
+     (parameters
+       (declare (in) vec4 p))
+     ((return (expression vec4 dFdy (var_ref p)))))
+ )
+
+ (function fwidth
+   (signature float
+     (parameters
+       (declare (in) float p))
+     ((return (expression float +
+                (expression float abs (expression float dFdx (var_ref p)))
+                (expression float abs (expression float dFdy (var_ref p)))))))
+
+   (signature vec2
+     (parameters
+       (declare (in) vec2 p))
+     ((return (expression vec2 +
+                (expression vec2 abs (expression vec2 dFdx (var_ref p)))
+                (expression vec2 abs (expression vec2 dFdy (var_ref p)))))))
+
+   (signature vec3
+     (parameters
+       (declare (in) vec3 p))
+     ((return (expression vec3 +
+                (expression vec3 abs (expression vec3 dFdx (var_ref p)))
+                (expression vec3 abs (expression vec3 dFdy (var_ref p)))))))
+
+   (signature vec4
+     (parameters
+       (declare (in) vec4 p))
+     ((return (expression vec4 +
+                (expression vec4 abs (expression vec4 dFdx (var_ref p)))
+                (expression vec4 abs (expression vec4 dFdy (var_ref p)))))))
+))