From 715633e0de101cb1a2b7b322455e4eab047f5f15 Mon Sep 17 00:00:00 2001
From: Ray <raysan5@gmail.com>
Date: Sun, 16 Jun 2024 10:41:47 +0200
Subject: [PATCH] REVIEWED: Spline cubic bezier example

---
 examples/shapes/shapes_splines_drawing.c | 37 ++++++++++++++++--------
 src/rshapes.c                            | 30 +++++++++----------
 2 files changed, 39 insertions(+), 28 deletions(-)

diff --git a/examples/shapes/shapes_splines_drawing.c b/examples/shapes/shapes_splines_drawing.c
index 0d5693eb2..7c099e7ef 100644
--- a/examples/shapes/shapes_splines_drawing.c
+++ b/examples/shapes/shapes_splines_drawing.c
@@ -56,6 +56,10 @@ int main(void)
         { 710.0f, 260.0f },
     };
     
+    // Array required for spline bezier-cubic, 
+    // including control points interleaved with start-end segment points
+    Vector2 pointsInterleaved[3*(MAX_SPLINE_POINTS - 1) + 1] = { 0 };
+    
     int pointCount = 5;
     int selectedPoint = -1;
     int focusedPoint = -1;
@@ -188,23 +192,32 @@ 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;
+                // NOTE: Cubic-bezier spline requires the 2 control points of each segnment to be 
+                // provided interleaved with the start and end point of every segment
+                for (int i = 0; i < (pointCount - 1); i++) 
+                {
+                    pointsInterleaved[3*i] = points[i];
+                    pointsInterleaved[3*i + 1] = control[i].start;
+                    pointsInterleaved[3*i + 2] = control[i].end;
                 }
-                fullPoints[3*(pointCount-1)] = points[pointCount-1],
-                DrawSplineBezierCubic(fullPoints, 3*(pointCount-1)+1, splineThickness, RED);
+                
+                pointsInterleaved[3*(pointCount - 1)] = points[pointCount - 1];
 
-                for (int i = 0; i < pointCount - 1; i++)
+                // Draw spline: cubic-bezier (with control points)
+                DrawSplineBezierCubic(pointsInterleaved, 3*(pointCount - 1) + 1, splineThickness, RED);
+                
+                /*
+                for (int i = 0; i < 3*(pointCount - 1); i += 3)
                 {
                     // Drawing individual segments, not considering thickness connection compensation
-                    // DrawSplineSegmentBezierCubic(points[i], control[i].start, control[i].end, points[i + 1], splineThickness, RED);
+                    DrawSplineSegmentBezierCubic(pointsInterleaved[i], pointsInterleaved[i + 1], pointsInterleaved[i + 2], pointsInterleaved[i + 3], splineThickness, MAROON);
+                }
+                */
 
-                    // Every cubic bezier point should have two control points
+                // Draw spline control points
+                for (int i = 0; i < pointCount - 1; i++)
+                {
+                    // Every cubic bezier point have two control points
                     DrawCircleV(control[i].start, 6, GOLD);
                     DrawCircleV(control[i].end, 6, GOLD);
                     if (focusedControlPoint == &control[i].start) DrawCircleV(control[i].start, 8, GREEN);
diff --git a/src/rshapes.c b/src/rshapes.c
index 2c4a57d38..95c54770e 100644
--- a/src/rshapes.c
+++ b/src/rshapes.c
@@ -1759,7 +1759,8 @@ void DrawSplineBasis(const Vector2 *points, int pointCount, float thick, Color c
         DrawTriangleStrip(vertices, 2*SPLINE_SEGMENT_DIVISIONS + 2, color);
     }
 
-    DrawCircleV(currentPoint, thick/2.0f, color);   // Draw end line circle-cap
+    // Cap circle drawing at the end of every segment
+    DrawCircleV(currentPoint, thick/2.0f, color);
 }
 
 // Draw spline: Catmull-Rom, minimum 4 points
@@ -1825,34 +1826,31 @@ void DrawSplineCatmullRom(const Vector2 *points, int pointCount, float thick, Co
         DrawTriangleStrip(vertices, 2*SPLINE_SEGMENT_DIVISIONS + 2, color);
     }
 
-    DrawCircleV(currentPoint, thick/2.0f, color);   // Draw end line circle-cap
+    // Cap circle drawing at the end of every segment
+    DrawCircleV(currentPoint, thick/2.0f, color);
 }
 
 // Draw spline: Quadratic Bezier, minimum 3 points (1 control point): [p1, c2, p3, c4...]
 void DrawSplineBezierQuadratic(const Vector2 *points, int pointCount, float thick, Color color)
 {
-    if (pointCount < 3) return;
-    for (int i = 2; i < pointCount - 2; i += 2)
-    {
-        DrawCircleV(points[i], thick/2.0f, color);
-    }
-    for (int i = 0; i < pointCount - 2; i += 2)
+    if (pointCount >= 3)
     {
-        DrawSplineSegmentBezierQuadratic(points[i], points[i + 1], points[i + 2], thick, color);
+        for (int i = 0; i < pointCount - 2; i += 2) DrawSplineSegmentBezierQuadratic(points[i], points[i + 1], points[i + 2], thick, color);
+        
+        // Cap circle drawing at the end of every segment
+        //for (int i = 2; i < pointCount - 2; i += 2) DrawCircleV(points[i], thick/2.0f, color);
     }
 }
 
 // Draw spline: Cubic Bezier, minimum 4 points (2 control points): [p1, c2, c3, p4, c5, c6...]
 void DrawSplineBezierCubic(const Vector2 *points, int pointCount, float thick, Color color)
 {
-    if (pointCount < 4) return;
-    for (int i = 3; i < pointCount - 3; i += 3)
-    {
-        DrawCircleV(points[i], thick/2.0f, color);
-    }
-    for (int i = 0; i < pointCount - 3; i += 3)
+    if (pointCount >= 4)
     {
-        DrawSplineSegmentBezierCubic(points[i], points[i + 1], points[i + 2], points[i + 3], thick, color);
+        for (int i = 0; i < pointCount - 3; i += 3) DrawSplineSegmentBezierCubic(points[i], points[i + 1], points[i + 2], points[i + 3], thick, color);
+        
+        // Cap circle drawing at the end of every segment
+        //for (int i = 3; i < pointCount - 3; i += 3) DrawCircleV(points[i], thick/2.0f, color);
     }
 }