Cycles: constant folding for RGB/Vector Curves and Color Ramp.

These are complex nodes, and it's conceivable they may end up constant
in some circumstances within node groups, so folding support is useful.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D2084

1 files changed, 8 insertions, 40 deletions

diff --git a/intern/cycles/kernel/shaders/node_vector_curves.osl b/intern/cycles/kernel/shaders/node_vector_curves.osl
index cff4efe1d98..d92fa11d439 100644
--- a/intern/cycles/kernel/shaders/node_vector_curves.osl
+++ b/intern/cycles/kernel/shaders/node_vector_curves.osl
@@ -14,43 +14,7 @@
  * limitations under the License.
  */
 
-#include "stdosl.h"
-#include "oslutil.h"
-
-float ramp_lookup(color ramp[], float at, int component)
-{
-	int table_size = arraylength(ramp);
-
-	if (at < 0.0 || at > 1.0) {
-		float t0, dy;
-		if (at < 0.0) {
-			t0 = ramp[0][component];
-			dy = t0 - ramp[1][component];
-			at = -at;
-		}
-		else {
-			t0 = ramp[table_size - 1][component];
-			dy = t0 - ramp[table_size - 2][component];
-			at = at - 1.0;
-		}
-		return t0 + dy * at * (table_size - 1);
-	}
-
-	float f = clamp(at, 0.0, 1.0) * (table_size - 1);
-
-	/* clamp int as well in case of NaN */
-	int i = (int)f;
-	if (i < 0) i = 0;
-	if (i >= table_size) i = table_size - 1;
-	float t = f - (float)i;
-
-	float result = ramp[i][component];
-
-	if (t > 0.0)
-		result = (1.0 - t) * result + t * ramp[i + 1][component];
-	
-	return result;
-}
+#include "node_ramp_util.h"
 
 shader node_vector_curves(
 	color ramp[] = {0.0},
@@ -63,9 +27,13 @@ shader node_vector_curves(
 {
 	vector c = (VectorIn - vector(min_x, min_x, min_x)) / (max_x - min_x);
 
-	VectorOut[0] = ramp_lookup(ramp, c[0], 0);
-	VectorOut[1] = ramp_lookup(ramp, c[1], 1);
-	VectorOut[2] = ramp_lookup(ramp, c[2], 2);
+	color r = rgb_ramp_lookup(ramp, c[0], 1, 1);
+	color g = rgb_ramp_lookup(ramp, c[0], 1, 1);
+	color b = rgb_ramp_lookup(ramp, c[0], 1, 1);
+
+	VectorOut[0] = r[0];
+	VectorOut[1] = g[1];
+	VectorOut[2] = b[2];
 
 	VectorOut = mix(VectorIn, VectorOut, Fac);
 }