Render simple shading via normals and provide a wireframe mode if necessary.

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

src/sig/Panel.java

@@ -77,7 +77,7 @@ public class Panel extends JPanel implements Runnable {
             for (int y=0;y<height;y++) {
                 boolean found=false;
                 if (!found) {
-                    p[ (int)(x*SigRenderer.RESOLUTION) + (int)(y*SigRenderer.RESOLUTION) * width] = Color.WHITE.getRGB();
+                    p[ (int)(x*SigRenderer.RESOLUTION) + (int)(y*SigRenderer.RESOLUTION) * width] = 0;
                 }
             }
         }   
@@ -130,9 +130,17 @@ public class Panel extends JPanel implements Runnable {
             if (normal.x*(triTranslated.A.x-SigRenderer.vCamera.x)+
                 normal.y*(triTranslated.A.y-SigRenderer.vCamera.y)+
                 normal.z*(triTranslated.A.z-SigRenderer.vCamera.z)<0) {
+
+                Vector3f lightDir = new Vector3f(0,0,-1);
+                l = (float)Math.sqrt(lightDir.x*lightDir.x+lightDir.y*lightDir.y+lightDir.z*lightDir.z);
+                lightDir.x/=l; lightDir.y/=l; lightDir.z/=l;
+
+                float dp = normal.x*lightDir.x+normal.y*lightDir.y+normal.z*lightDir.z;
+
                 Matrix.MultiplyMatrixVector(triTranslated.A, triProjected.A, SigRenderer.matProj);
                 Matrix.MultiplyMatrixVector(triTranslated.B, triProjected.B, SigRenderer.matProj);
                 Matrix.MultiplyMatrixVector(triTranslated.C, triProjected.C, SigRenderer.matProj);
+                triProjected.setColor(new Color(dp,dp,dp));
 
                 triProjected.A.x+=1f;
                 triProjected.A.y+=1f;
@@ -147,7 +155,10 @@ public class Panel extends JPanel implements Runnable {
                 triProjected.C.x*=0.5f*SigRenderer.SCREEN_WIDTH;
                 triProjected.C.y*=0.5f*SigRenderer.SCREEN_HEIGHT;
 
-                DrawUtils.DrawTriangle(p,(int)triProjected.A.x,(int)triProjected.A.y,(int)triProjected.B.x,(int)triProjected.B.y,(int)triProjected.C.x,(int)triProjected.C.y,Color.BLACK);
+                DrawUtils.FillTriangle(p,(int)triProjected.A.x,(int)triProjected.A.y,(int)triProjected.B.x,(int)triProjected.B.y,(int)triProjected.C.x,(int)triProjected.C.y,triProjected.getColor());
+                if (SigRenderer.WIREFRAME) {
+                    DrawUtils.DrawTriangle(p,(int)triProjected.A.x,(int)triProjected.A.y,(int)triProjected.B.x,(int)triProjected.B.y,(int)triProjected.C.x,(int)triProjected.C.y,Color.BLACK);
+                }
             }
         }
         i += 1;

src/sig/SigRenderer.java

@@ -4,6 +4,9 @@ import javax.vecmath.Matrix4f;
 import javax.vecmath.Point2d;
 import javax.vecmath.Tuple3d;
 import javax.vecmath.Vector3f;
+
+import sig.utils.DrawUtils;
+
 import java.awt.event.MouseEvent;
 import java.awt.event.MouseListener; 
 import java.awt.event.MouseMotionListener;
@@ -18,6 +21,9 @@ import java.awt.Dimension;
 import java.awt.BorderLayout;
 
 public class SigRenderer implements KeyListener,MouseListener,MouseMotionListener{
+
+    public static boolean WIREFRAME = false;
+
     public static Mesh cube;
     public static int SCREEN_WIDTH=1280;
     public static int SCREEN_HEIGHT=720;

src/sig/Triangle.java

@@ -1,8 +1,10 @@
 package sig;
 import javax.vecmath.Vector3f;
+import java.awt.Color;
 
 public class Triangle {
     Vector3f A,B,C;
+    Color col = Color.WHITE;
     Triangle(Vector3f A,Vector3f B,Vector3f C) {
         this.A=A;
         this.B=B;
@@ -16,4 +18,10 @@ public class Triangle {
     public String toString() {
         return "Triangle [A=" + A + ", B=" + B + ", C=" + C + "]";
     }
+    public Color getColor() {
+        return col;
+    }
+    public void setColor(Color col) {
+        this.col=col;
+    }
 }

src/sig/utils/DrawUtils.java

@@ -1,10 +1,150 @@
 package sig.utils;
 
 import java.awt.Color;
+import java.util.Arrays;
 
 import sig.SigRenderer;
 
 public class DrawUtils {
+    static void drawLine(int[] canvas,int sx,int ex,int ny,Color col) {
+        for (int i=sx;i<=ex;i++) {
+            Draw(canvas,i,ny,col);
+        }
+    }
+    public static void FillTriangle(int[] canvas,int x1, int y1, int x2, int y2, int x3, int y3, Color col)
+	{
+		int t1x=0, t2x=0, y=0, minx=0, maxx=0, t1xp=0, t2xp=0;
+		boolean changed1 = false;
+		boolean changed2 = false;
+		int signx1=0, signx2=0, dx1=0, dy1=0, dx2=0, dy2=0;
+		int e1=0, e2=0;
+		// Sort vertices
+		if (y1>y2) {int t=y1;y1=y2;y2=t;t=x1;x1=x2;x2=t;}
+		if (y1>y3) {int t=y1;y1=y3;y3=t;t=x1;x1=x3;x3=t;}
+		if (y2>y3) {int t=y2;y2=y3;y3=t;t=x2;x2=x3;x3=t;}
+
+		t1x = t2x = x1; y = y1;   // Starting points
+		dx1 = (int)(x2 - x1); if (dx1<0) { dx1 = -dx1; signx1 = -1; }
+		else signx1 = 1;
+		dy1 = (int)(y2 - y1);
+
+		dx2 = (int)(x3 - x1); if (dx2<0) { dx2 = -dx2; signx2 = -1; }
+		else signx2 = 1;
+		dy2 = (int)(y3 - y1);
+
+		if (dy1 > dx1) {   // swap values
+			int t=dx1;dx1=dy1;dy1=t;
+			changed1 = true;
+		}
+		if (dy2 > dx2) {   // swap values
+            int t=dy2;dy2=dx2;dx2=t;
+			changed2 = true;
+		}
+
+		e2 = (int)(dx2 >> 1);
+		// Flat top, just process the second half
+        boolean goNext=false;
+		if (y1 == y2) goNext=true;
+        if (!goNext) {
+            e1 = (int)(dx1 >> 1);
+
+            for (int i = 0; i < dx1;) {
+                t1xp = 0; t2xp = 0;
+                if (t1x<t2x) { minx = t1x; maxx = t2x; }
+                else { minx = t2x; maxx = t1x; }
+                // process first line until y value is about to change
+                loop3:
+                while (i<dx1) {
+                    i++;
+                    e1 += dy1;
+                    while (e1 >= dx1) {
+                        e1 -= dx1;
+                        if (changed1) t1xp = signx1;//t1x += signx1;
+                        else break loop3;
+                    }
+                    if (changed1) break;
+                    else t1x += signx1;
+                }
+                // Move line
+                // process second line until y value is about to change
+                loop2:
+                while (true) {
+                    e2 += dy2;
+                    while (e2 >= dx2) {
+                        e2 -= dx2;
+                        if (changed2) t2xp = signx2;//t2x += signx2;
+                        else break loop2;
+                    }
+                    if (changed2)     break;
+                    else              t2x += signx2;
+                }
+                if (minx>t1x) minx = t1x; if (minx>t2x) minx = t2x;
+                if (maxx<t1x) maxx = t1x; if (maxx<t2x) maxx = t2x;
+                drawLine(canvas,minx, maxx, y,col);    // Draw line from min to max points found on the y
+                                            // Now increase y
+                if (!changed1) t1x += signx1;
+                t1x += t1xp;
+                if (!changed2) t2x += signx2;
+                t2x += t2xp;
+                y += 1;
+                if (y == y2) break;
+
+            }
+        }
+		// Second half
+		dx1 = (int)(x3 - x2); if (dx1<0) { dx1 = -dx1; signx1 = -1; }
+		else signx1 = 1;
+		dy1 = (int)(y3 - y2);
+		t1x = x2;
+
+		if (dy1 > dx1) {   // swap values
+            int t=dy1;dy1=dx1;dx1=t;
+			changed1 = true;
+		}
+		else changed1 = false;
+
+		e1 = (int)(dx1 >> 1);
+
+		for (int i = 0; i <= dx1; i++) {
+			t1xp = 0; t2xp = 0;
+			if (t1x<t2x) { minx = t1x; maxx = t2x; }
+			else { minx = t2x; maxx = t1x; }
+			// process first line until y value is about to change
+            loop3:
+			while (i<dx1) {
+				e1 += dy1;
+				while (e1 >= dx1) {
+					e1 -= dx1;
+					if (changed1) { t1xp = signx1; break; }//t1x += signx1;
+					else break loop3;
+				}
+				if (changed1) break;
+				else   	   	  t1x += signx1;
+				if (i<dx1) i++;
+			}
+            // process second line until y value is about to change
+            loop2:
+            while (t2x != x3) {
+                e2 += dy2;
+                while (e2 >= dx2) {
+                    e2 -= dx2;
+                    if (changed2) t2xp = signx2;
+                    else break loop2;
+                }
+                if (changed2)     break;
+                else              t2x += signx2;
+            }
+			if (minx>t1x) minx = t1x; if (minx>t2x) minx = t2x;
+			if (maxx<t1x) maxx = t1x; if (maxx<t2x) maxx = t2x;
+			drawLine(canvas,minx, maxx, y,col);   										
+			if (!changed1) t1x += signx1;
+			t1x += t1xp;
+			if (!changed2) t2x += signx2;
+			t2x += t2xp;
+			y += 1;
+			if (y>y3) return;
+		}
+	}
     public static void DrawTriangle(int[]canvas,int x1,int y1,int x2,int y2,int x3,int y3,Color col) {
         DrawLine(canvas,x1,y1,x2,y2,col);
         DrawLine(canvas,x2,y2,x3,y3,col);