Correct linear curve GPU sided

CurveTools/src/GPU/Core/Lineargenerator.cu

@@ -10,21 +10,32 @@ namespace ct::gpu {
     : StreamedGenerator() {}
 
     __host__ Point LinearGenerator::generate(const thrust::universal_vector<Point> & ctrlPoint, const float t) const {
+        if(ctrlPoint.empty()) {
+			return Point(0.0);
+		}
         size_t max_size = ctrlPoint.size();
 
+		if(max_size == 1) {
+			return  Point(ctrlPoint[0].x, ctrlPoint[0].y, ctrlPoint[0].z);
+		}
+
         float range = 1.f/static_cast<float>(max_size);
         size_t current = 0;
     
-        for(float i = 0.f; i <= t; i += range) {
+        for(float i = 0.f; i < t; i += range) {
             ++current;
         }
 
-        if(current == max_size) {
-            --current;
+        if(current == 0) {
+            ++current;
+        }
+
+        if(current >= max_size) {
+			current = max_size-1;
 		}
 
-        Point p1 = ctrlPoint[current];
-        Point p2 = ctrlPoint[current+1];
+        Point p1 = ctrlPoint[current-1];
+        Point p2 = ctrlPoint[current];
 
         Point r, * d_r;
         cudaMalloc(&d_r, sizeof(Point));