Scale trails to viewport + Cleanup

Author: MEEPofFaith

src/progressed/graphics/draw3d/Perspective.java

@@ -11,6 +11,7 @@
 
 public class Perspective{
     private static final Vec2 offsetPos = new Vec2();
+    private static final Vec3 scalingPos = new Vec3();
     /** Viewport offset from the camera height in world units. */
     public static float viewportOffset = 16f;
     /** Field of View in degrees */
@@ -46,16 +47,9 @@ public static Vec2 drawPos(float x, float y, float z){
         //viewport
         float vw = viewportSize.x, vh = viewportSize.y;
         float cx = camera.position.x, cy = camera.position.y;
-        float cz = cameraZ;
-
-        x -= cx;
-        y -= cy;
-        z = cz - z;
-
-        float vx = x / z * viewportOffset,
-            vy = y / z * viewportOffset;
+        Vec3 scaled = scaleToViewport(x, y, z);
 
-        offsetPos.set(vx / vw * camera.width, vy / vh * camera.height).add(cx, cy);
+        offsetPos.set(scaled.x / vw * camera.width, scaled.y / vh * camera.height).add(cx, cy);
         return offsetPos;
     }
 
@@ -122,7 +116,7 @@ public static void viewportSize(){
         }
     }
 
-    public static float dstToViewport(float x, float y, float z){
+    public static Vec3 scaleToViewport(float x, float y, float z){
         float cx = camera.position.x, cy = camera.position.y;
         float cz = cameraZ;
 
@@ -134,7 +128,13 @@ public static float dstToViewport(float x, float y, float z){
             vy = y / zz * viewportOffset;
         float vz = viewportZ();
 
-        return Math3D.dst(x, y, z, vx, vy, vz); //Distance between viewport and pos
+        return scalingPos.set(vx, vy, vz);
+    }
+
+    public static float dstToViewport(float x, float y, float z){
+        Vec3 scaled = scaleToViewport(x, y, z);
+        float cx = camera.position.x, cy = camera.position.y;
+        return scaled.dst(x - cx, y - cy, z);
     }
 
     /**

src/progressed/graphics/trails/ZTrail.java

@@ -73,35 +73,53 @@ public void draw(Color color, float width, boolean fade){
         float lastAngle = 0;
         float[] items = points.items;
         float size = width / (int)(points.size / 4);
+        float vz = Perspective.viewportZ();
+        boolean calcLast = true;
 
         for(int i = 0; i < points.size; i += 4){
             float px1 = items[i], py1 = items[i + 1], z1 = items[i + 3];
+            float z2 = i < points.size - 4 ? items[i + 4 + 3] : lastZ;
+
+            if(z1 > vz && z2 > vz){
+                calcLast = true;
+                continue;
+            }
+
+            if(z1 > vz){ //Scale to near plane
+                Vec3 pos = Perspective.scaleToViewport(px1, py1, z1);
+                px1 = pos.x;
+                py1 = pos.y;
+                z1 = pos.z;
+            }
+
             Vec2 pos1 = Perspective.drawPos(px1, py1, z1);
             float x1 = pos1.x, y1 = pos1.y, w1 = Perspective.scale(items[i], items[i + 1], z1);
-            float x2, y2, px2, py2, w2, z2;
+            float px2, py2, x2, y2, w2;
 
             //last position is always lastX/Y/W
             if(i < points.size - 4){
                 px2 = items[i + 4];
                 py2 = items[i + 4 + 1];
-                z2 = items[i + 4 + 3];
-                Vec2 pos2 = Perspective.drawPos(px2, py2, z2);
-                x2 = pos2.x;
-                y2 = pos2.y;
-                w2 = Perspective.scale(items[i + 4], items[i + 4 + 1], z2);
             }else{
                 px2 = lastX;
                 py2 = lastY;
-                z2 = lastZ;
-                Vec2 pos2 = Perspective.drawPos(px2, py2, z2);
-                x2 = pos2.x;
-                y2 = pos2.y;
-                w2 = Perspective.scale(lastX, lastY, z2);
             }
 
+            if(z2 > vz){ //Scale to near plane
+                Vec3 pos = Perspective.scaleToViewport(px2, py2, z2);
+                px2 = pos.x;
+                py2 = pos.y;
+                z2 = pos.z;
+            }
+
+            Vec2 pos2 = Perspective.drawPos(px2, py2, z2);
+            x2 = pos2.x;
+            y2 = pos2.y;
+            w2 = Perspective.scale(px2, py2, z2);
+
             float a2 = -Angles.angleRad(x1, y1, x2, y2);
             //end of the trail (i = 0) has the same angle as the next.
-            float a1 = i == 0 ? a2 : lastAngle;
+            float a1 = calcLast ? a2 : lastAngle;
             if(w1 <= 0.001f || w2 <= 0.001f) continue;
 
             float
@@ -125,6 +143,7 @@ public void draw(Color color, float width, boolean fade){
             );
 
             lastAngle = a2;
+            calcLast = false;
         }
 
         Draw.color();