IECoreScene CurvesPrimitiveEvaluator : fix vTangent() error

proberts-cinesite · proberts-cinesite · commit bdd5b73e7eb3 · 2025-06-05T16:10:36.000+01:00
`IECoreScene.CurvesPrimitiveEvaluator.Result.vTangent()` now returns vector pointing in the correct (opposite) direction for curves with `Linear` interpolation.
diff --git a/Changes b/Changes
@@ -1,7 +1,10 @@
 10.5.x.x (relative to 10.5.9.2)
 ========
 
+Fixes
+-----
 
+- IECoreScene.CurvesPrimitiveEvaluator.Result : Fixed error in `vTangent()` function causing tangent to point in opposite direction for curves with `Linear` interpolation.
 
 
 10.5.9.2 (relative to 10.5.9.1)
diff --git a/src/IECoreScene/CurvesPrimitiveEvaluator.cpp b/src/IECoreScene/CurvesPrimitiveEvaluator.cpp
@@ -260,8 +260,8 @@ void CurvesPrimitiveEvaluator::Result::init( unsigned curveIndex, float v, const
 	{
 		m_coefficients[0] = 1.0f - m_segmentV;
 		m_coefficients[1] = m_segmentV;
-		m_derivativeCoefficients[0] = 1.0f;
-		m_derivativeCoefficients[1] = -1.0f;
+		m_derivativeCoefficients[0] = -1.0f;
+		m_derivativeCoefficients[1] = 1.0f;
 		m_vertexDataIndices[0] = m_varyingDataIndices[0] = o + i;
 		if( periodic )
 		{

Original file line number	Diff line number	Diff line change
`@@ -260,8 +260,8 @@ void CurvesPrimitiveEvaluator::Result::init( unsigned curveIndex, float v, const`
`260`	`260`	`{`
`261`	`261`	`m_coefficients[0] = 1.0f - m_segmentV;`
`262`	`262`	`m_coefficients[1] = m_segmentV;`
`263`		`- m_derivativeCoefficients[0] = 1.0f;`
`264`		`- m_derivativeCoefficients[1] = -1.0f;`
	`263`	`+ m_derivativeCoefficients[0] = -1.0f;`
	`264`	`+ m_derivativeCoefficients[1] = 1.0f;`
`265`	`265`	`m_vertexDataIndices[0] = m_varyingDataIndices[0] = o + i;`
`266`	`266`	`if( periodic )`
`267`	`267`	`{`