Fix wrong logic causing excessive software transform fallback if cull planes are missing. Minor cleanup.

GPU/Common/SoftwareTransformCommon.cpp

@@ -438,6 +438,22 @@ inline bool IsInsideFarPlane(const TransformedVertex& v) {
 	return v.z <= v.pos_w;
 }
 
+// TODO: Use CrossSIMD, should help.
+inline void LerpTransformedVertex(TransformedVertex *dest, TransformedVertex &a, TransformedVertex &b, float t) {
+	dest->x = a.x + (b.x - a.x) * t;
+	dest->y = a.y + (b.y - a.y) * t;
+	dest->z = a.z + (b.z - a.z) * t;
+	dest->pos_w = a.pos_w + (b.pos_w - a.pos_w) * t;
+	dest->u = a.u + (b.u - a.u) * t;
+	dest->v = a.v + (b.v - a.v) * t;
+	dest->uv_w = a.uv_w + (b.uv_w - a.uv_w) * t;
+	dest->fog = a.fog + (b.fog - a.fog) * t;
+
+	// note: colorBlend is backwards.
+	dest->color0_32 = colorBlend(b.color0_32, a.color0_32, t);
+	dest->color1_32 = colorBlend(b.color1_32, a.color1_32, t);
+}
+
 // Generated by Gemini, and adapted to fit.
 void ClipTrianglesAgainstNearPlane(
 	TransformedVertex *transformed, int &transformedCount, int maxTransformed,
@@ -528,7 +544,7 @@ void ClipTrianglesAgainstNearPlane(
 
 					// Generate new vertex at the intersection point
 					TransformedVertex newVertex;
-					TransformedVertex::Lerp(&newVertex, const_cast<TransformedVertex&>(a), const_cast<TransformedVertex&>(b), t);
+					LerpTransformedVertex(&newVertex, const_cast<TransformedVertex&>(a), const_cast<TransformedVertex&>(b), t);
 
 					// Force exact intersection to eliminate precision creeping down the pipeline
 					newVertex.z = -newVertex.pos_w;