ADDED: `GetSplinePoint*()` functions for spline evaluation

RENAMED: `DrawLine<spline_type>()` to `DrawSpline<spline_type>()` for more consistent and clear naming
REVIEWED: Bezier drawing parameters order, more consistent
REVIEWED: Spline-based examples -WIP-

2 files changed, 85 insertions, 37 deletions

diff --git a/examples/shapes/shapes_lines_bezier.c b/examples/shapes/shapes_lines_bezier.c
index 7d7bdb0c..5bd916ee 100644
--- a/examples/shapes/shapes_lines_bezier.c
+++ b/examples/shapes/shapes_lines_bezier.c
@@ -30,7 +30,7 @@ int main(void)
     Vector2 end = { (float)screenWidth, (float)screenHeight };
     
     Vector2 startControl = { 100, 0 };
-    Vector2 endControl = { (float)GetScreenWidth() - 100, (float)GetScreenHeight() };
+    Vector2 endControl = { GetScreenWidth() - 100, GetScreenHeight() };
 
     SetTargetFPS(60);               // Set our game to run at 60 frames-per-second
     //--------------------------------------------------------------------------------------
@@ -60,9 +60,11 @@ int main(void)
 
             DrawText("USE MOUSE LEFT-RIGHT CLICK to DEFINE LINE START and END POINTS", 15, 20, 20, GRAY);
 
-            //DrawLineBezier(start, end, 2.0f, RED);
+            // Draw line cubic-bezier, in-out interpolation (easing), no control points
+            DrawLineBezier(start, end, 3.0f, BLUE);
             
-            DrawLineBezierCubic(start, end, startControl, endControl, 2.0f, RED);
+            // Draw spline cubic-bezier with control points
+            DrawSplineBezierCubic(start, startControl, endControl, end, 2.0f, RED);
             
             DrawLineEx(start, startControl, 1.0, LIGHTGRAY);
             DrawLineEx(end, endControl, 1.0, LIGHTGRAY);
diff --git a/examples/shapes/shapes_lines_splines.c b/examples/shapes/shapes_splines_drawing.c
index c020c60b..711aad21 100644
--- a/examples/shapes/shapes_lines_splines.c
+++ b/examples/shapes/shapes_splines_drawing.c
@@ -13,13 +13,25 @@
 
 #include "raylib.h"
 
-#define MAX_CONTROL_POINTS      32
+#include <stdlib.h>     // Required for: NULL
 
+#define MAX_SPLINE_POINTS      32
+
+// Bezier spline control points
+// NOTE: Every segment has two control points 
 typedef struct {
     Vector2 start;
     Vector2 end;
 } ControlPoint;
 
+// Spline types
+typedef enum {
+    SPLINE_LINEAR = 0,
+    SPLINE_BASIS,       // B-Spline
+    SPLINE_CATMULLROM,
+    SPLINE_BEZIER
+} SplineType;
+
 //------------------------------------------------------------------------------------
 // Program main entry point
 //------------------------------------------------------------------------------------
@@ -33,7 +45,7 @@ int main(void)
     SetConfigFlags(FLAG_MSAA_4X_HINT);
     InitWindow(screenWidth, screenHeight, "raylib [shapes] example - splines drawing");
 
-    Vector2 points[MAX_CONTROL_POINTS] = {
+    Vector2 points[MAX_SPLINE_POINTS] = {
         { 100.0f, 200.0f },
         { 300.0f, 400.0f },
         { 500.0f, 300.0f },
@@ -43,15 +55,18 @@ int main(void)
     
     int pointCount = 5;
     int selectedPoint = -1;
+    int focusedPoint = -1;
+    Vector2 *selectedControlPoint = NULL;
+    Vector2 *focusedControlPoint = NULL;
     
-    int splineType = 0;             // 0-Linear, 1-BSpline, 2-CatmullRom, 3-Bezier
+    int splineType = SPLINE_LINEAR; // 0-Linear, 1-BSpline, 2-CatmullRom, 3-Bezier
     
-    // Cubic Bezier control points
-    ControlPoint control[MAX_CONTROL_POINTS] = { 0 };
+    // Cubic Bezier control points initialization
+    ControlPoint control[MAX_SPLINE_POINTS] = { 0 };
     for (int i = 0; i < pointCount - 1; i++)
     {
-        control[i].start = points[i];
-        control[i].end = points[i + 1];
+        control[i].start = (Vector2){ points[i].x - 20, points[i].y - 20 };
+        control[i].end = (Vector2){ points[i + 1].x + 20, points[i + 1].y + 20 };
     }
     
     SetTargetFPS(60);               // Set our game to run at 60 frames-per-second
@@ -62,30 +77,60 @@ int main(void)
     {
         // Update
         //----------------------------------------------------------------------------------
-        // Points movement logic
-        if (IsMouseButtonPressed(MOUSE_RIGHT_BUTTON) && (pointCount < MAX_CONTROL_POINTS))
+        // Spline points creation logic (at the end of spline)
+        if (IsMouseButtonPressed(MOUSE_RIGHT_BUTTON) && (pointCount < MAX_SPLINE_POINTS))
         {
             points[pointCount] = GetMousePosition();
             pointCount++;
         }
 
+        // Spline point focus and selection logic
         for (int i = 0; i < pointCount; i++)
         {
-            if (IsMouseButtonDown(MOUSE_LEFT_BUTTON) && CheckCollisionPointCircle(GetMousePosition(), points[i], 6.0f))
+            if (CheckCollisionPointCircle(GetMousePosition(), points[i], 8.0f))
             {
-                selectedPoint = i;
+                focusedPoint = i;
+                if (IsMouseButtonDown(MOUSE_LEFT_BUTTON)) selectedPoint = i; 
                 break;
             }
+            else focusedPoint = -1;
         }
-
+        
+        // Spline point movement logic
         if (selectedPoint >= 0)
         {
             points[selectedPoint] = GetMousePosition();
             if (IsMouseButtonReleased(MOUSE_LEFT_BUTTON)) selectedPoint = -1;
         }
         
-        // TODO: Cubic Bezier spline control points logic
-        
+        // Cubic Bezier spline control points logic
+        if ((splineType == SPLINE_BEZIER) && (focusedPoint == -1))
+        {
+            // Spline control point focus and selection logic
+            for (int i = 0; i < pointCount; i++)
+            {
+                if (CheckCollisionPointCircle(GetMousePosition(), control[i].start, 6.0f))
+                {
+                    focusedControlPoint = &control[i].start;
+                    if (IsMouseButtonDown(MOUSE_LEFT_BUTTON)) selectedControlPoint = &control[i].start; 
+                    break;
+                }
+                else if (CheckCollisionPointCircle(GetMousePosition(), control[i].end, 6.0f))
+                {
+                    focusedControlPoint = &control[i].end;
+                    if (IsMouseButtonDown(MOUSE_LEFT_BUTTON)) selectedControlPoint = &control[i].end; 
+                    break;
+                }
+                else focusedControlPoint = NULL;
+            }
+            
+            // Spline control point movement logic
+            if (selectedControlPoint != NULL)
+            {
+                *selectedControlPoint = GetMousePosition();
+                if (IsMouseButtonReleased(MOUSE_LEFT_BUTTON)) selectedControlPoint = NULL;
+            }
+        }
         
         // Spline selection logic
         if (IsKeyPressed(KEY_ONE)) splineType = 0;
@@ -100,47 +145,48 @@ int main(void)
 
             ClearBackground(RAYWHITE);
         
-            if (splineType == 0)        // Linear
+            if (splineType == SPLINE_LINEAR)
             {
-                // Draw linear spline
-                for (int i = 0; i < pointCount - 1; i++)
-                {
-                    DrawLineEx(points[i], points[i + 1], 2.0f, RED);
-                }
+                // Draw spline: linear
+                DrawSplineLinear(points, pointCount, 2.0f, RED);
             }
-            else if (splineType == 1)   // B-Spline
+            else if (splineType == SPLINE_BASIS)
             {
-                // Draw b-spline
-                DrawLineBSpline(points, pointCount, 2.0f, RED);
-                //for (int i = 0; i < (pointCount - 3); i++) DrawLineBSplineSegment(points[i], points[i + 1], points[i + 2], points[i + 3], 24.0f, BLUE);
+                // Draw spline: basis
+                DrawSplineBasis(points, pointCount, 2.0f, RED);
+                //for (int i = 0; i < (pointCount - 3); i++) DrawSplineBasisSegment(points[i], points[i + 1], points[i + 2], points[i + 3], 24.0f, BLUE);
             }
-            else if (splineType == 2)   // CatmullRom Spline
+            else if (splineType == SPLINE_CATMULLROM)
             {
                 // Draw spline: catmull-rom
-                DrawLineCatmullRom(points, pointCount, 2.0f, RED);
-                //for (int i = 0; i < (pointCount - 3); i++) DrawLineCatmullRomSegment(points[i], points[i + 1], points[i + 2], points[i + 3], 24.0f, Fade(BLUE, 0.4f));
+                DrawSplineCatmullRom(points, pointCount, 2.0f, RED);
+                //for (int i = 0; i < (pointCount - 3); i++) DrawSplineCatmullRomSegment(points[i], points[i + 1], points[i + 2], points[i + 3], 24.0f, Fade(BLUE, 0.4f));
             }
-            else if (splineType == 3)   // Cubic Bezier
+            else if (splineType == SPLINE_BEZIER)
             {
-                // Draw line bezier cubic (with control points)
+                // Draw spline: cubic-bezier (with control points)
                 for (int i = 0; i < pointCount - 1; i++)
                 {
-                    DrawLineBezierCubic(points[i], points[i + 1], control[i].start, control[i + 1].end, 2.0f, RED);
+                    DrawSplineBezierCubic(points[i], control[i].start, control[i].end, points[i + 1], 2.0f, RED);
 
-                    // TODO: Every cubic bezier point should have two control points
+                    // Every cubic bezier point should have two control points
                     DrawCircleV(control[i].start, 4, GOLD);
                     DrawCircleV(control[i].end, 4, GOLD);
+                    if (focusedControlPoint == &control[i].start) DrawCircleV(control[i].start, 6, GREEN);
+                    else if (focusedControlPoint == &control[i].end) DrawCircleV(control[i].end, 6, GREEN);
                     DrawLineEx(points[i], control[i].start, 1.0, LIGHTGRAY);
                     DrawLineEx(points[i + 1], control[i].end, 1.0, LIGHTGRAY);
                 }
             }
 
-            // Draw control points
+            // Draw spline key-points
             for (int i = 0; i < pointCount; i++)
             {
-                DrawCircleV(points[i], 6.0f, RED);
-                if ((splineType != 0) && (i < pointCount - 1)) DrawLineV(points[i], points[i + 1], GRAY);
+                DrawCircleV(points[i], (focusedPoint == i)? 8.0f : 5.0f, (focusedPoint == i)? BLUE: RED);
+                if ((splineType != 0) && (i < pointCount - 1)) DrawLineV(points[i], points[i + 1], LIGHTGRAY);
             }
+            
+            // TODO: Draw help
 
         EndDrawing();
         //----------------------------------------------------------------------------------