Do not render faces that are on the "insides" of a structure.

Co-authored-by: sigonasr2 <sigonasr2@gmail.com>

src/sig/Block.java

@@ -1,10 +1,47 @@
 package sig;
 
+import java.util.ArrayList;
+import java.util.List;
+
 public class Block {
     Vector pos;
     Mesh block;
+    FaceList neighbors;
     Block(Vector pos,Mesh block) {
+        this.neighbors=new FaceList();
         this.pos=pos;
-        this.block=block;
+        List<Triangle> newTris = new ArrayList<>();
+        for (Triangle t : block.triangles) {
+            Triangle newT = (Triangle)t.clone();
+            newT.b=this;
+            newTris.add(newT);
+        }
+        this.block=new Mesh(newTris);
+    }
+    public void updateFaces() {
+        if (SigRenderer.blockGrid.containsKey(pos.x+"_"+(pos.y+1)+"_"+pos.z)) {
+            neighbors.UP=true;
+            SigRenderer.blockGrid.get(pos.x+"_"+(pos.y+1)+"_"+pos.z).neighbors.DOWN=true;
+        }
+        if (SigRenderer.blockGrid.containsKey(pos.x+"_"+(pos.y-1)+"_"+pos.z)) {
+            neighbors.DOWN=true;
+            SigRenderer.blockGrid.get(pos.x+"_"+(pos.y-1)+"_"+pos.z).neighbors.UP=true;
+        }
+        if (SigRenderer.blockGrid.containsKey((pos.x-1)+"_"+(pos.y)+"_"+pos.z)) {
+            neighbors.LEFT=true;
+            SigRenderer.blockGrid.get((pos.x-1)+"_"+(pos.y)+"_"+pos.z).neighbors.RIGHT=true;
+        }
+        if (SigRenderer.blockGrid.containsKey((pos.x+1)+"_"+(pos.y)+"_"+pos.z)) {
+            neighbors.RIGHT=true;
+            SigRenderer.blockGrid.get((pos.x+1)+"_"+(pos.y)+"_"+pos.z).neighbors.LEFT=true;
+        }
+        if (SigRenderer.blockGrid.containsKey(pos.x+"_"+(pos.y)+"_"+(pos.z+1))) {
+            neighbors.FORWARD=true;
+            SigRenderer.blockGrid.get(pos.x+"_"+(pos.y)+"_"+(pos.z+1)).neighbors.BACKWARD=true;
+        }
+        if (SigRenderer.blockGrid.containsKey(pos.x+"_"+(pos.y)+"_"+(pos.z-1))) {
+            neighbors.BACKWARD=true;
+            SigRenderer.blockGrid.get(pos.x+"_"+(pos.y)+"_"+(pos.z-1)).neighbors.FORWARD=true;
+        }
     }
 }

src/sig/FaceList.java

@@ -0,0 +1,10 @@
+package sig;
+
+public class FaceList {
+    boolean UP=false; //+Y
+    boolean DOWN=false;
+    boolean FORWARD=false; //+Z
+    boolean RIGHT=false; //+X
+    boolean LEFT=false;
+    boolean BACKWARD=false;
+}

src/sig/Panel.java

@@ -103,11 +103,10 @@ public class Panel extends JPanel implements Runnable {
         Matrix matCamera = Matrix.PointAt(SigRenderer.vCamera, vTarget, vUp);
         Matrix matView = Matrix.QuickInverse(matCamera);
 
-        for (Block b : SigRenderer.blocks) {
+        for (Triangle t : SigRenderer.triRender) {
-            for (Triangle t : b.block.triangles) {
             Triangle triProjected = new Triangle(),triTransformed=new Triangle(),triViewed=new Triangle();
 
-                matWorld = Matrix.MakeTranslation(b.pos.x,b.pos.y,b.pos.z);
+            matWorld = Matrix.MakeTranslation(t.b.pos.x,t.b.pos.y,t.b.pos.z);
             
             triTransformed.A = Matrix.MultiplyVector(matWorld,t.A);
             triTransformed.B = Matrix.MultiplyVector(matWorld,t.B);
@@ -116,6 +115,7 @@ public class Panel extends JPanel implements Runnable {
             triTransformed.U = t.U;
             triTransformed.V = t.V;
             triTransformed.tex = t.tex;
+            triTransformed.b=t.b;
 
             Vector normal=new Vector(),line1=new Vector(),line2=new Vector();
             line1 = Vector.subtract(triTransformed.B,triTransformed.A);
@@ -137,18 +137,15 @@ public class Panel extends JPanel implements Runnable {
                 float dp = Math.max(0.1f,Math.min(1,(1f/((cameraRay2.x-center.x)*(cameraRay2.x-center.x)+
                 (cameraRay2.y-center.y)*(cameraRay2.y-center.y)+
                 (cameraRay2.z-center.z)*(cameraRay2.z-center.z))*4)));*/
-                    float dp = Math.max(0.1f,Math.min(1,(1f/((b.pos.x-SigRenderer.vCamera.x)+
+                float dp = Math.max(0.1f,Math.min(1,(1f/((triTransformed.b.pos.x-SigRenderer.vCamera.x)*(triTransformed.b.pos.x-SigRenderer.vCamera.x)+
-                    (b.pos.y-SigRenderer.vCamera.y)*(b.pos.y-SigRenderer.vCamera.y)+
+                (triTransformed.b.pos.y-SigRenderer.vCamera.y)*(triTransformed.b.pos.y-SigRenderer.vCamera.y)+
-                    (b.pos.z-SigRenderer.vCamera.z)*(b.pos.z-SigRenderer.vCamera.z))*4)));
+                (triTransformed.b.pos.z-SigRenderer.vCamera.z)*(triTransformed.b.pos.z-SigRenderer.vCamera.z))*4)));
 
                 triViewed.A = Matrix.MultiplyVector(matView,triTransformed.A);
                 triViewed.B = Matrix.MultiplyVector(matView,triTransformed.B);
                 triViewed.C = Matrix.MultiplyVector(matView,triTransformed.C);
+                triTransformed.copyExtraDataTo(triViewed);
                 triViewed.setColor(new Color(dp,dp,dp));
-                    triViewed.T = triTransformed.T;
-                    triViewed.U = triTransformed.U;
-                    triViewed.V = triTransformed.V;
-                    triViewed.tex = triTransformed.tex;
 
                 int clippedTriangles = 0;
                 Triangle[] clipped = new Triangle[]{new Triangle(),new Triangle()};
@@ -166,6 +163,7 @@ public class Panel extends JPanel implements Runnable {
                     triProjected.T = (Vector2)clipped[i].T.clone();
                     triProjected.U = (Vector2)clipped[i].U.clone();
                     triProjected.V = (Vector2)clipped[i].V.clone();
+                    triProjected.b=clipped[i].b;
 
                     triProjected.T.u = triProjected.T.u/triProjected.A.w;
                     triProjected.U.u = triProjected.U.u/triProjected.B.w;
@@ -204,7 +202,6 @@ public class Panel extends JPanel implements Runnable {
                 }
             }
         } 
-        }
 
         /*Collections.sort(accumulatedTris, new Comparator<Triangle>() {
             @Override
@@ -214,8 +211,8 @@ public class Panel extends JPanel implements Runnable {
                 return (z1<z2)?1:(z1==z2)?0:-1;
             }
         });*/
-
         for (Triangle t : accumulatedTris) {
+            
             Triangle[] clipped = new Triangle[]{new Triangle(),new Triangle()};
             List<Triangle> triList = new ArrayList<>();
             triList.add(t);
@@ -258,11 +255,11 @@ public class Panel extends JPanel implements Runnable {
 
     public void repaint() {
         super.repaint();
-        startTime = System.nanoTime();
     }
 
     @Override
     public void paintComponent(Graphics g) {
+        startTime = System.nanoTime();
         super.paintComponent(g);
         // perform draws on pixels
         render();

src/sig/SigRenderer.java

@@ -12,7 +12,9 @@ import java.awt.event.KeyEvent;
 import java.awt.event.KeyListener;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.awt.Toolkit;
 import java.awt.BorderLayout;
 
@@ -20,7 +22,7 @@ public class SigRenderer implements KeyListener,MouseListener,MouseMotionListene
 
     public static boolean WIREFRAME = false;
 
-    public static List<Block> blocks = new ArrayList<Block>();
+    public static List<Triangle> triRender = new ArrayList<>();
     public static int SCREEN_WIDTH=1280;
     public static int SCREEN_HEIGHT=720;
     public final static long TIMEPERTICK = 16666667l;
@@ -28,6 +30,7 @@ public class SigRenderer implements KeyListener,MouseListener,MouseMotionListene
     public static float DRAWLOOPTIME=0;
     public static final float RESOLUTION=1;
     public static float rot = (float)Math.PI/4; //In radians.
+    public static Map<String,Block> blockGrid = new HashMap<>();
 
     public static List<Pixel> pixels;
 
@@ -37,7 +40,7 @@ public class SigRenderer implements KeyListener,MouseListener,MouseMotionListene
     public static float fAspectRatio = (float)SCREEN_HEIGHT/SCREEN_WIDTH;
     public static Matrix matProj = Matrix.MakeProjection(fFov,fAspectRatio,fNear,fFar);
 
-    public static Vector vCamera = new Vector();
+    public static Vector vCamera = new Vector(0.5f,2f,0.5f);
     public static Vector vLookDir = new Vector(0,0,1);
     public static float yaw = 0;
     public static float pitch = 0;
@@ -50,6 +53,8 @@ public class SigRenderer implements KeyListener,MouseListener,MouseMotionListene
 
     public static float[] depthBuffer;
 
+    public static Mesh DIRT_CUBE=new Mesh("cube.obj","dirt.png");
+
     boolean upHeld=false,downHeld=false,leftHeld=false,rightHeld=false,
     aHeld=false,sHeld=false,dHeld=false,wHeld=false;
 
@@ -83,15 +88,31 @@ public class SigRenderer implements KeyListener,MouseListener,MouseMotionListene
         }
     }
 
+    public static void addBlock(Vector pos,Mesh type) {
+        Block b = new Block(pos,type);
+        blockGrid.put(pos.x+"_"+pos.y+"_"+pos.z,b);
+        b.updateFaces();
+        updateRenderGrid();
+    }
+
+    public static void updateRenderGrid() {
+        triRender.clear();
+        for (String key : blockGrid.keySet()) {
+            Block b = blockGrid.get(key);
+            if (!b.neighbors.UP) {triRender.add(b.block.triangles.get(8));triRender.add(b.block.triangles.get(9));}
+            if (!b.neighbors.DOWN) {triRender.add(b.block.triangles.get(10));triRender.add(b.block.triangles.get(11));}
+            if (!b.neighbors.LEFT) {triRender.add(b.block.triangles.get(6));triRender.add(b.block.triangles.get(7));}
+            if (!b.neighbors.RIGHT) {triRender.add(b.block.triangles.get(2));triRender.add(b.block.triangles.get(3));}
+            if (!b.neighbors.FORWARD) {triRender.add(b.block.triangles.get(4));triRender.add(b.block.triangles.get(5));}
+            if (!b.neighbors.BACKWARD) {triRender.add(b.block.triangles.get(0));triRender.add(b.block.triangles.get(1));}
+        }  
+    }
+
     SigRenderer(JFrame f) {
         //cube = new Mesh(OBJReader.ReadOBJFile("teapot.obj",false));
-        Mesh dirtCube = new Mesh("cube.obj","dirt.png");
+        for (int x=0;x<16;x++) {
-        for (int x=0;x<32;x++) {
+            for (int z=0;z<16;z++) {
-            for (int y=0;y<32;y++) {
+                addBlock(new Vector(x,0,z),DIRT_CUBE);
-                blocks.add(new Block(
-                    new Vector(x,0,y),
-                    dirtCube
-                ));
             }
         }
 

src/sig/Triangle.java

@@ -5,6 +5,7 @@ public class Triangle {
     Vector A,B,C;
     Vector2 T,U,V;
     Color col = Color.WHITE;
+    Block b = null;
     public Texture tex = null;
     public Triangle() {
         this(new Vector(),new Vector(),new Vector());
@@ -20,10 +21,20 @@ public class Triangle {
         this.U=U;
         this.V=V;
     }
+    public void copyExtraDataTo(Triangle targetTriangle) {
+        targetTriangle.T=this.T;
+        targetTriangle.U=this.U;
+        targetTriangle.V=this.V;
+        targetTriangle.col=this.col;
+        targetTriangle.tex=this.tex;
+        targetTriangle.b=this.b;
+    }
     @Override
     protected Object clone(){
-        Triangle t = new Triangle((Vector)this.A.clone(),(Vector)this.B.clone(),(Vector)this.C.clone());
+        Triangle t = new Triangle((Vector)this.A.clone(),(Vector)this.B.clone(),(Vector)this.C.clone(),(Vector2)this.T.clone(),(Vector2)this.U.clone(),(Vector2)this.V.clone());
         t.col = col;
+        t.tex=tex;
+        t.b=b;
         return t;
     }
     @Override
@@ -88,6 +99,7 @@ public class Triangle {
             ExtraData t = new ExtraData(0);
             out_tri[0].col = in.col;
             out_tri[0].tex = in.tex;
+            out_tri[0].b=in.b;
             out_tri[0].A = inside_points[0];
             out_tri[0].T = inside_tex[0];
             out_tri[0].B = Vector.IntersectPlane(plane_p, plane_n, inside_points[0], outside_points[0],t);
@@ -104,6 +116,7 @@ public class Triangle {
             ExtraData t = new ExtraData(0);
             out_tri[0].col=out_tri[1].col=in.col;
             out_tri[0].tex=out_tri[1].tex=in.tex;
+            out_tri[0].b=out_tri[1].b=in.b;
             out_tri[0].A = inside_points[0];
             out_tri[0].B = inside_points[1];
             out_tri[0].T = inside_tex[0];