Support for unit missiles

core/src/mindustry/graphics/Trail.java

@@ -10,7 +10,7 @@ public class Trail{
     public int length;
 
     private final FloatSeq points;
-    private float lastX = -1, lastY = -1, lastAngle = -1, counter = 0f;
+    private float lastX = -1, lastY = -1, lastAngle = -1, counter = 0f, lastW = 0f;
 
     public Trail(int length){
         this.length = length;
@@ -26,6 +26,10 @@ public class Trail{
         return out;
     }
 
+    public float width(){
+        return lastW;
+    }
+
     public void clear(){
         points.clear();
     }
@@ -49,23 +53,43 @@ public class Trail{
     public void draw(Color color, float width){
         Draw.color(color);
         float[] items = points.items;
-        float lx = lastX, ly = lastY, lastAngle = this.lastAngle;
+        float lastAngle = this.lastAngle;
+        float size = width / (points.size / 3);
 
-        for(int i = 0; i < points.size - 3; i+= 3){
-            float x1 = items[i], y1 = items[i + 1], w1 = items[i + 2],
-            x2 = items[i + 3], y2 = items[i + 4], w2 = items[i + 5];
-            float size = width / (points.size/3);
-            float z1 = lastAngle;
-            float z2 = -Angles.angleRad(x2, y2, lx, ly);
+        for(int i = 0; i < points.size; i += 3){
+            float x1 = items[i], y1 = items[i + 1], w1 = items[i + 2];
+            float x2, y2, w2;
+
+            //last position is always lastX/Y/W
+            if(i < points.size - 3){
+                x2 = items[i + 3];
+                y2 = items[i + 4];
+                w2 = items[i + 5];
+            }else{
+                x2 = lastX;
+                y2 = lastY;
+                w2 = lastW;
+            }
+
+            float z2 = -Angles.angleRad(x1, y1, x2, y2);
+            //end of the trail (i = 0) has the same angle as the next.
+            float z1 = i == 0 ? z2 : lastAngle;
             if(w1 <= 0.001f || w2 <= 0.001f) continue;
 
-            float cx = Mathf.sin(z1) * i/3f * size * w1, cy = Mathf.cos(z1) * i/3f * size * w1,
-                nx = Mathf.sin(z2) * (i/3f + 1) * size * w2, ny = Mathf.cos(z2) * (i/3f + 1) * size * w2;
-            Fill.quad(x1 - cx, y1 - cy, x1 + cx, y1 + cy, x2 + nx, y2 + ny, x2 - nx, y2 - ny);
+            float
+                cx = Mathf.sin(z1) * i/3f * size * w1,
+                cy = Mathf.cos(z1) * i/3f * size * w1,
+                nx = Mathf.sin(z2) * (i/3f + 1) * size * w2,
+                ny = Mathf.cos(z2) * (i/3f + 1) * size * w2;
+
+            Fill.quad(
+                x1 - cx, y1 - cy,
+                x1 + cx, y1 + cy,
+                x2 + nx, y2 + ny,
+                x2 - nx, y2 - ny
+            );
 
             lastAngle = z2;
-            lx = x2;
-            ly = y2;
         }
 
         Draw.reset();
@@ -89,19 +113,21 @@ public class Trail{
 
     /** Adds a new point to the trail at intervals. */
     public void update(float x, float y, float width){
-        if((counter += Time.delta) >= 0.99f){
+        //TODO fix longer trails at low FPS
+        if((counter += Time.delta) >= 1f){
             if(points.size > length*3){
                 points.removeRange(0, 2);
             }
 
-            lastAngle = -Angles.angleRad(x, y, lastX, lastY);
-
             points.add(x, y, width);
 
-            lastX = x;
-            lastY = y;
-
-            counter = 0f;
+            counter %= 1f;
         }
+
+        //update last position regardless, so it joins
+        lastAngle = -Angles.angleRad(x, y, lastX, lastY);
+        lastX = x;
+        lastY = y;
+        lastW = width;
     }
 }