[rshapes] Fix multisegment Bezier splines. (#3744)

* [rshapes] Fix multisegment Bezier splines.

It seems to me that these functions are wrong, if you step the index by 1 you move to a control point instead of the next segment.

* Fix example shapes/shapes_splines_drawing for bezier splines.

* Draw circles to fill gaps between bezier segments.

examples/shapes/shapes_splines_drawing.c

@@ -63,7 +63,7 @@ int main(void)
     Vector2 *focusedControlPoint = NULL;
     
     // Cubic Bezier control points initialization
-    ControlPoint control[MAX_SPLINE_POINTS] = { 0 };
+    ControlPoint control[MAX_SPLINE_POINTS-1] = { 0 };
     for (int i = 0; i < pointCount - 1; i++)
     {
         control[i].start = (Vector2){ points[i].x + 50, points[i].y };
@@ -88,6 +88,9 @@ int main(void)
         if (IsMouseButtonPressed(MOUSE_RIGHT_BUTTON) && (pointCount < MAX_SPLINE_POINTS))
         {
             points[pointCount] = GetMousePosition();
+            int i = pointCount - 1;
+            control[i].start = (Vector2){ points[i].x + 50, points[i].y };
+            control[i].end = (Vector2){ points[i + 1].x - 50, points[i + 1].y };
             pointCount++;
         }
 
@@ -114,7 +117,7 @@ int main(void)
         if ((splineTypeActive == SPLINE_BEZIER) && (focusedPoint == -1))
         {
             // Spline control point focus and selection logic
-            for (int i = 0; i < pointCount; i++)
+            for (int i = 0; i < pointCount - 1; i++)
             {
                 if (CheckCollisionPointCircle(GetMousePosition(), control[i].start, 6.0f))
                 {
@@ -186,10 +189,20 @@ int main(void)
             else if (splineTypeActive == SPLINE_BEZIER)
             {
                 // Draw spline: cubic-bezier (with control points)
+
+                Vector2 fullPoints[3*(MAX_SPLINE_POINTS-1)+1] = {0};
+                for (int i = 0; i < pointCount-1; i++) {
+                    fullPoints[3*i] = points[i];
+                    fullPoints[3*i+1] = control[i].start;
+                    fullPoints[3*i+2] = control[i].end;
+                }
+                fullPoints[3*(pointCount-1)] = points[pointCount-1],
+                DrawSplineBezierCubic(fullPoints, 3*(pointCount-1)+1, splineThickness, RED);
+
                 for (int i = 0; i < pointCount - 1; i++)
                 {
                     // Drawing individual segments, not considering thickness connection compensation
-                    DrawSplineSegmentBezierCubic(points[i], control[i].start, control[i].end, points[i + 1], splineThickness, RED);
+                    // DrawSplineSegmentBezierCubic(points[i], control[i].start, control[i].end, points[i + 1], splineThickness, RED);
 
                     // Every cubic bezier point should have two control points
                     DrawCircleV(control[i].start, 6, GOLD);

src/rshapes.c

@@ -1832,8 +1832,11 @@ void DrawSplineCatmullRom(const Vector2 *points, int pointCount, float thick, Co
 void DrawSplineBezierQuadratic(const Vector2 *points, int pointCount, float thick, Color color)
 {
     if (pointCount < 3) return;
-
+    for (int i = 2; i < pointCount - 2; i += 2)
-    for (int i = 0; i < pointCount - 2; i++)
+    {
+        DrawCircleV(points[i], thick/2.0f, color);
+    }
+    for (int i = 0; i < pointCount - 2; i += 2)
     {
         DrawSplineSegmentBezierQuadratic(points[i], points[i + 1], points[i + 2], thick, color);
     }
@@ -1843,8 +1846,11 @@ void DrawSplineBezierQuadratic(const Vector2 *points, int pointCount, float thic
 void DrawSplineBezierCubic(const Vector2 *points, int pointCount, float thick, Color color)
 {
     if (pointCount < 4) return;
-
+    for (int i = 3; i < pointCount - 3; i += 3)
-    for (int i = 0; i < pointCount - 3; i++)
+    {
+        DrawCircleV(points[i], thick/2.0f, color);
+    }
+    for (int i = 0; i < pointCount - 3; i += 3)
     {
         DrawSplineSegmentBezierCubic(points[i], points[i + 1], points[i + 2], points[i + 3], thick, color);
     }