Cycles Hair: Introduction of Cardinal Spline Curve Segments and minor fixes.

The curve segment primitive has been added. This includes an intersection function and changes to the BVH.

A few small errors in the line segment intersection routine are also fixed.

intern/cycles/render/curves.h

@@ -29,6 +29,8 @@ class DeviceScene;
 class Progress;
 class Scene;
 
+void curvebounds(float *lower, float *upper, float3 *p, int dim);
+
 typedef enum curve_presets {
 	CURVE_CUSTOM,
 	CURVE_TANGENT_SHADING,
@@ -39,13 +41,14 @@ typedef enum curve_presets {
 typedef enum curve_primitives {
 	CURVE_TRIANGLES,
 	CURVE_LINE_SEGMENTS,
-	CURVE_SEGMENTS
+	CURVE_SEGMENTS,
+	CURVE_RIBBONS
 } curve_primitives;
 
 typedef enum curve_triangles {
-	CURVE_CAMERA,
-	CURVE_RIBBONS,
-	CURVE_TESSELATED
+	CURVE_CAMERA_TRIANGLES,
+	CURVE_RIBBON_TRIANGLES,
+	CURVE_TESSELATED_TRIANGLES
 } curve_triangles;
 
 typedef enum curve_lines {
@@ -98,6 +101,7 @@ public:
 	int triangle_method;
 	int resolution;
 	int segments;
+	int subdivisions;
 
 	float normalmix;
 	float encasing_ratio;