Scale line points to viewport height

Author: MEEPofFaith

src/progressed/graphics/draw3d/Draw3D.java

@@ -126,7 +126,7 @@ public static void drawDiskDebug(float x1, float y1, float x2, float y2, float z
     public static void drawLineDebug(float x1, float y1, float z1, float x2, float y2, float z2){
         Lines3D.line(x1, y1, z1, x2, y2, z2);
 
-        int pointCount = Lines3D.linePointCounts(x1, y1, z1, x2, y2, z2);
+        int pointCount = Lines3D.linePointCount(x1, y1, z1, x2, y2, z2);
         float[] points = Lines3D.linePoints(x1, y1, z1, x2, y2, z2, pointCount);
         for(int i = 0; i < points.length; i += 3){
             float x = points[i],

src/progressed/graphics/draw3d/Lines3D.java

@@ -50,7 +50,7 @@ public static void line(float x1, float y1, float z1, float x2, float y2, float
     }
 
     public static void line(float x1, float y1, float z1, float x2, float y2, float z2, boolean scale){
-        line(x1, y1, z1, x2, y2, z2, linePointCounts(x1, y1, z1, x2, y2, z2), scale);
+        line(x1, y1, z1, x2, y2, z2, linePointCount(x1, y1, z1, x2, y2, z2), scale);
     }
 
     public static void line(float x1, float y1, float z1, float x2, float y2, float z2){
@@ -62,21 +62,36 @@ public static void lineAngleBase(float x, float y, float z, float length, float
         line(x, y, z, x + Tmp.v31.x, y + Tmp.v31.y, z + Tmp.v31.z);
     }
 
-    public static int linePointCounts(float x1, float y1, float z1, float x2, float y2, float z2){
+    public static int linePointCount(float x1, float y1, float z1, float x2, float y2, float z2){
         return (int)(Math3D.dst(x1, y1, z1, x2, y2, z2) / tilesize / tilesize);
     }
 
     public static float[] linePoints(float x1, float y1, float z1, float x2, float y2, float z2, int pointCount){
         if(z1 > z2){ //Always return from bottom to top
-            return linePoints(x2, y2, z2, x1, y1, z1, pointCount);
+            float tx = x1, ty = y1, tz = z1;
+            x1 = x2;
+            y1 = y2;
+            z1 = z2;
+            x2 = tx;
+            y2 = ty;
+            z2 = tz;
+        }
+
+        float vz = Perspective.viewportZ();
+        if(z2 > vz){ //If line goes above viewport height, scale to viewport height.
+            float scl = vz / (z2 - z1);
+            x2 = x1 + (x2 - x1) * scl;
+            y2 = y1 + (y2 - y1) * scl;
+            z2 = vz;
+            pointCount = Mathf.ceil(pointCount * scl);
         }
 
         float[] points = new float[pointCount * 3];
         float px = (x2 - x1) / (pointCount - 1);
         float py = (y2 - y1) / (pointCount - 1);
         float pz = (z2 - z1) / (pointCount - 1);
 
-        for(int i = 0; i < pointCount; i++){ //TODO check if goes above viewport z. If so, limit to viewport and cut short.
+        for(int i = 0; i < pointCount; i++){
             points[i * 3] = x1 + px * i;
             points[i * 3 + 1] = y1 + py * i;
             points[i * 3 + 2] = z1 + pz * i;

src/progressed/graphics/draw3d/Perspective.java

@@ -83,13 +83,23 @@ public static float alpha(float x, float y, float z){
         }
     }
 
-    /** Calculates the camera height based on FOV and the size of the vanilla camera. */
+    /**
+     * Calculates the camera z coordinate based on FOV and the size of the vanilla camera.
+     * @return camera z coordinate
+     * */
     public static float cameraZ(){
         float width = Math.max(camera.width, camera.height) / 2f;
         //TOA
         return (float)(width / Math.tan(fov / 2f * Mathf.degRad));
     }
 
+    /**
+     * @return viewport z coordinate
+     */
+    public static float viewportZ(){
+        return cameraZ() - viewportOffset;
+    }
+
     /** Calculates the size of the viewport. */
     public static  Vec2 viewportSize(){
         float v1 = (float)(Math.tan(fov / 2f * Mathf.degRad) * viewportOffset * 2f);