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.

1 files changed, 80 insertions, 27 deletions

diff --git a/intern/cycles/render/curves.cpp b/intern/cycles/render/curves.cpp
index 3299503b4ab..3ee441ef095 100644
--- a/intern/cycles/render/curves.cpp
+++ b/intern/cycles/render/curves.cpp
@@ -29,6 +29,52 @@
 
 CCL_NAMESPACE_BEGIN
 
+/* Curve functions */
+
+void curvebounds(float *lower, float *upper, float3 *p, int dim)
+{
+	float *p0 = &p[0].x;
+	float *p1 = &p[1].x;
+	float *p2 = &p[2].x;
+	float *p3 = &p[3].x;
+	float fc = 0.71f;
+	float curve_coef[4];
+	curve_coef[0] = p1[dim];
+	curve_coef[1] = -fc*p0[dim] + fc*p2[dim];
+	curve_coef[2] = 2.0f * fc * p0[dim] + (fc - 3.0f) * p1[dim] + (3.0f - 2.0f * fc) * p2[dim] - fc * p3[dim];
+	curve_coef[3] = -fc * p0[dim] + (2.0f - fc) * p1[dim] + (fc - 2.0f) * p2[dim] + fc * p3[dim];
+	float discroot = curve_coef[2] * curve_coef[2] - 3 * curve_coef[3] * curve_coef[1];
+	float ta = -1.0f;
+	float tb = -1.0f;
+	if(discroot >= 0) {
+		discroot = sqrt(discroot);
+		ta = (-curve_coef[2] - discroot) / (3 * curve_coef[3]);
+		tb = (-curve_coef[2] + discroot) / (3 * curve_coef[3]);
+		ta = (ta > 1.0f || ta < 0.0f) ? -1.0f : ta;
+		tb = (tb > 1.0f || tb < 0.0f) ? -1.0f : tb;
+	}
+
+	*upper = max(p1[dim],p2[dim]);
+	*lower = min(p1[dim],p2[dim]);
+	float exa = p1[dim];
+	float exb = p2[dim];
+	float t2;
+	float t3;
+	if(ta >= 0.0f) {
+		t2 = ta * ta;
+		t3 = t2 * ta;
+		exa = curve_coef[3] * t3 + curve_coef[2] * t2 + curve_coef[1] * ta + curve_coef[0];
+	}
+	if(tb >= 0.0f) {
+		t2 = tb * tb;
+		t3 = t2 * tb;
+		exb = curve_coef[3] * t3 + curve_coef[2] * t2 + curve_coef[1] * tb + curve_coef[0];
+	}
+	*upper = max(*upper, max(exa,exb));
+	*lower = min(*lower, min(exa,exb));
+	
+}
+
 /* Hair System Manager */
 
 CurveSystemManager::CurveSystemManager()
@@ -36,9 +82,10 @@ CurveSystemManager::CurveSystemManager()
 	primitive = CURVE_LINE_SEGMENTS;
 	line_method = CURVE_CORRECTED;
 	interpolation = CURVE_CARDINAL;
-	triangle_method = CURVE_CAMERA;
+	triangle_method = CURVE_CAMERA_TRIANGLES;
 	resolution = 3;
 	segments = 1;
+	subdivisions = 3;
 
 	normalmix = 1.0f;
 	encasing_ratio = 1.01f;
@@ -75,31 +122,36 @@ void CurveSystemManager::device_update(Device *device, DeviceScene *dscene, Scen
 
 	kcurve->curveflags = 0;
 
-	if(primitive == CURVE_SEGMENTS)
-		kcurve->curveflags |= CURVE_KN_INTERPOLATE;
-
-	if(line_method == CURVE_ACCURATE)
-		kcurve->curveflags |= CURVE_KN_ACCURATE;
-	if(line_method == CURVE_CORRECTED)
-		kcurve->curveflags |= CURVE_KN_INTERSECTCORRECTION;
-	if(line_method == CURVE_POSTCORRECTED)
-		kcurve->curveflags |= CURVE_KN_POSTINTERSECTCORRECTION;
-
-	if(use_tangent_normal)
-		kcurve->curveflags |= CURVE_KN_TANGENTGNORMAL;
-	if(use_tangent_normal_correction)
-		kcurve->curveflags |= CURVE_KN_NORMALCORRECTION;
-	if(use_tangent_normal_geometry)
-		kcurve->curveflags |= CURVE_KN_TRUETANGENTGNORMAL;
-	if(use_joined)
-		kcurve->curveflags |= CURVE_KN_CURVEDATA;
-	if(use_backfacing)
-		kcurve->curveflags |= CURVE_KN_BACKFACING;
-	if(use_encasing)
-		kcurve->curveflags |= CURVE_KN_ENCLOSEFILTER;
-
-	kcurve->normalmix = normalmix;
-	kcurve->encasing_ratio = encasing_ratio;
+	if(use_curves) {
+		if(primitive == CURVE_SEGMENTS || primitive == CURVE_RIBBONS)
+			kcurve->curveflags |= CURVE_KN_INTERPOLATE;
+		if(primitive == CURVE_RIBBONS)
+			kcurve->curveflags |= CURVE_KN_RIBBONS;
+
+		if(line_method == CURVE_ACCURATE)
+			kcurve->curveflags |= CURVE_KN_ACCURATE;
+		if(line_method == CURVE_CORRECTED)
+			kcurve->curveflags |= CURVE_KN_INTERSECTCORRECTION;
+		if(line_method == CURVE_POSTCORRECTED)
+			kcurve->curveflags |= CURVE_KN_POSTINTERSECTCORRECTION;
+
+		if(use_tangent_normal)
+			kcurve->curveflags |= CURVE_KN_TANGENTGNORMAL;
+		if(use_tangent_normal_correction)
+			kcurve->curveflags |= CURVE_KN_NORMALCORRECTION;
+		if(use_tangent_normal_geometry)
+			kcurve->curveflags |= CURVE_KN_TRUETANGENTGNORMAL;
+		if(use_joined)
+			kcurve->curveflags |= CURVE_KN_CURVEDATA;
+		if(use_backfacing)
+			kcurve->curveflags |= CURVE_KN_BACKFACING;
+		if(use_encasing)
+			kcurve->curveflags |= CURVE_KN_ENCLOSEFILTER;
+
+		kcurve->normalmix = normalmix;
+		kcurve->encasing_ratio = encasing_ratio;
+		kcurve->subdivisions = subdivisions;
+	}
 
 	if(progress.get_cancel()) return;
 
@@ -130,7 +182,8 @@ bool CurveSystemManager::modified(const CurveSystemManager& CurveSystemManager)
 		use_curves == CurveSystemManager.use_curves &&
 		use_joined == CurveSystemManager.use_joined &&
 		segments == CurveSystemManager.segments &&
-		use_parents == CurveSystemManager.use_parents);
+		use_parents == CurveSystemManager.use_parents &&
+		subdivisions == CurveSystemManager.subdivisions);
 }
 
 bool CurveSystemManager::modified_mesh(const CurveSystemManager& CurveSystemManager)