Implemented new accurate turret prediction

2018-05-06 10:54:18 -04:00
parent f8a4128c88
commit c74ee2150c
3 changed files with 68 additions and 10 deletions
@@ -0,0 +1,60 @@
+package io.anuke.mindustry.entities;
+
+import com.badlogic.gdx.math.Vector2;
+import io.anuke.ucore.util.Mathf;
+
+public class Predict {
+    private static Vector2 vec = new Vector2();
+    private static Vector2 vresult = new Vector2();
+
+    public static Vector2 intercept(float srcx, float srcy, float dstx, float dsty, float dstvx, float dstvy, float v) {
+        float tx = dstx - srcx,
+                ty = dsty - srcy,
+                tvx = dstvx,
+                tvy = dstvy;
+
+        // Get quadratic equation components
+        float a = tvx*tvx + tvy*tvy - v*v;
+        float b = 2 * (tvx * tx + tvy * ty);
+        float c = tx*tx + ty*ty;
+
+        // Solve quadratic
+        Vector2 ts = quad(a, b, c); // See quad(), below
+
+        // Find smallest positive solution
+        Vector2 sol = vresult.set(0, 0);
+        if (ts != null) {
+            float t0 = ts.x, t1 = ts.y;
+            float t = Math.min(t0, t1);
+            if (t < 0) t = Math.max(t0, t1);
+            if (t > 0) {
+                sol.set(dstx + dstvx*t, dsty + dstvy*t);
+            }
+        }
+
+        return sol;
+    }
+
+
+    /**
+     * Return solutions for quadratic
+     */
+    public static Vector2 quad(float a, float b, float c) {
+        Vector2 sol = null;
+        if (Math.abs(a) < 1e-6) {
+            if (Math.abs(b) < 1e-6) {
+                sol = Math.abs(c) < 1e-6 ? vec.set(0,0) : null;
+            } else {
+                vec.set(-c/b, -c/b);
+            }
+        } else {
+            float disc = b*b - 4*a*c;
+            if (disc >= 0) {
+                disc = Mathf.sqrt(disc);
+                a = 2*a;
+                sol = vec.set((-b-disc)/a, (-b+disc)/a);
+            }
+        }
+        return sol;
+    }
+}