import java.awt.*; import java.lang.*; public class Triangle2D implements Drawable { protected Vertex2D v[]; protected EdgeEqn edge[]; protected float twiceArea; protected static byte sort[][]= {{0, 1},{1, 2},{0, 2},{2, 0},{2, 1},{1, 0}}; protected int vtxSortX[]; protected int vtxSortY[]; protected int noseNegY, nosePosY, ltBreak, rtBreak; protected int activeEdge[]; /////// CONSTRUCTORS ///////////////////////////// // zero argument constructor for future expansion public Triangle2D() {;} // constructor using three Vertex2D public Triangle2D( Vertex2D v0, Vertex2D v1, Vertex2D v2 ) { v = new Vertex2D[3]; v[0]=v0; v[1]=v1; v[2]=v2; v[0].setVertexNo(0); v[1].setVertexNo(1); v[2].setVertexNo(2); vtxSortX = new int[3]; vtxSortY = new int[3]; noseNegY= -1; nosePosY= -1; ltBreak = -1; rtBreak = -1; activeEdge = new int[2]; } ///////// METHODS //////////////////////////// protected boolean triangleSetup(Raster r) { //System.out.println("IN TRIANGLESETP(RASTER)" ); if (edge == null) edge = new EdgeEqn[3]; //Compute the three edge equations edge[2] = new EdgeEqn(2, v[0], v[1]); edge[0] = new EdgeEqn(0, v[1], v[2]); edge[1] = new EdgeEqn(1, v[2], v[0]); //Trick #1: Orient edges so that the triangle's interior lies within all of //their positive half-spaces. Assuring that the area is positive accomplishes this twiceArea = edge[0].getC() + edge[1].getC() + edge[2].getC(); if (twiceArea < 0) { edge[0].flip(); edge[1].flip(); edge[2].flip(); twiceArea = -twiceArea ; } // if ( twiceArea < 1.0f){ // // System.out.println("HAS TO RETURN FALSE"); // return false; //>0 is implicit. // } //System.out.println("IF TWICEAREA < 1, SHOULDN'T RUN THIS"); //area of smallest triangle = 0.5*1*1 //for(int j=0; j<3; j++ ) System.out.println("edge["+j+"].A=" + edge[j].getA() + "B=" + edge[j].getB()+ "C=" + edge[j].getC() ); //Trick #2: compute bounding box int xflag = edge[2].flag + 2*edge[0].flag + 4*edge[1].flag; int yflag = (xflag >> 3) - 1; xflag = (xflag & 7) - 1; vtxSortX[0] = sort[xflag][0]; vtxSortX[2] = sort[xflag][1]; vtxSortX[1] = 3 - ( vtxSortX[0] + vtxSortX[2] ); vtxSortY[0] = sort[yflag][1]; vtxSortY[2] = sort[yflag][0]; vtxSortY[1] = 3 - ( vtxSortY[0] + vtxSortY[2] ); // for( int kk=0; kk<3; kk++){ // System.out.println("vtxSortX["+kk+"]= " + vtxSortX[kk] ); // System.out.println("vtxSortY["+kk+"]= " + vtxSortY[kk] ); // } isNoBreakPoint(); /* //clip triangle's bounding box to raster xMin = (xMin < 0) ? 0 : xMin; xMax = (xMax >= r.width) ? r.width - 1 : xMax; yMin = (yMin < 0) ? 0 : yMin; yMax = (yMax >= r.height) ? r.height - 1 : yMax; */ // System.out.println("noseNegY="+ noseNegY + "nosePosY="+ nosePosY + "ltBreak=" +ltBreak + "rtBreak=" + rtBreak); return true; } protected void isNoBreakPoint() { //System.out.println("IN ISNOBREAKPOINT" ); int i=0; int flag = 0; do { if( edge[i].horiz ) { flag = 1; noseNegY = i; } i++; } while( (flag==0) && (i<3) ); if( flag==1 ){ if( noseNegY==vtxSortY[0] ){ return; } else { nosePosY=noseNegY; noseNegY= -1; return; } } float x = v[vtxSortY[1]].getx(); float y = v[vtxSortY[1]].gety(); if( (vtxSortY[1] !=vtxSortX[2])&&(edge[vtxSortY[1]].findXAtGivenY(y) > x) ) { ltBreak = vtxSortY[1]; return; } if( (vtxSortY[1] !=vtxSortX[0])&&(edge[vtxSortY[1]].findXAtGivenY(y) < x ) ) { rtBreak = vtxSortY[1]; return; } return; } //ISNOBREAKPOINT //this will always return first the edge closer to x=0 and then the one further away public void getActiveEdges( ) { //System.out.println("IN GETACTIVEEDGES(void)" ); if( noseNegY >= 0 ) { activeEdge[0] = getEdgeNo( noseNegY+1 ); activeEdge[1] = getEdgeNo( noseNegY-1 ); return; } if( nosePosY >= 0 ) { activeEdge[0] = getEdgeNo( nosePosY-1 ); activeEdge[1] = getEdgeNo( nosePosY+1 ); return; } return; }//GETACTIVEEDGES //this will always return first the edge closer to x=0 and then the one further away public void getActiveEdges( boolean isBeforeBreak) { //System.out.println("IN GETACTIVEEDGES(isBeforeBreak)" ); if( ltBreak >= 0) { if( isBeforeBreak ) { activeEdge[0] = getEdgeNo( ltBreak-1 ); activeEdge[1] = getEdgeNo( ltBreak ); } else { activeEdge[0] = getEdgeNo( ltBreak+1 ); activeEdge[1] = getEdgeNo( ltBreak ); } return; } if( rtBreak >= 0) { if( isBeforeBreak ) { activeEdge[0] = getEdgeNo( rtBreak ); activeEdge[1] = getEdgeNo( rtBreak+1 ); } else { activeEdge[0] = getEdgeNo( rtBreak ); activeEdge[1] = getEdgeNo( rtBreak-1 ); } return; } return; }//GETACTIVEEDGES //returns edge number between 0 and 2, irrespective of "int someNo" public int getEdgeNo( int someNo ){ if( someNo >= 3 ) return( getEdgeNo(someNo-3) ); if( someNo < 0 ) return( getEdgeNo(someNo+3) ); return someNo; } public int getVertexNo(int someNo ){ if( someNo >= 3 ) return( getVertexNo(someNo-3) ); if( someNo < 0 ) return( getVertexNo(someNo+3) ); return someNo; } public void draw( Raster r) { //System.out.println("IN TRIANGLE2D.DRAW" ); if( ! this.triangleSetup(r)){ //System.out.println("TWICE AREA <1 => DRAW EDGE/VERTEX" ); for(int i=0; i<3; i++ ) edge[i].drawLine(r); return; } //System.out.println("WILL DRAW SIMPLE TRIANGLE" ); if( noseNegY >= 0){ getActiveEdges(); drawSpan( activeEdge, v[ getVertexNo(noseNegY) ], v[ getVertexNo(noseNegY-1) ], r ); } if( nosePosY >= 0){ getActiveEdges(); drawSpan( activeEdge, v[ getVertexNo(nosePosY+1) ], v[ getVertexNo(nosePosY) ], r ); } if( ltBreak >= 0){ getActiveEdges(true); drawSpan( activeEdge, v[ getVertexNo(ltBreak+1) ], v[ getVertexNo(ltBreak) ], r ); getActiveEdges(false); drawSpan( activeEdge, v[ getVertexNo(ltBreak) ], v[ getVertexNo(ltBreak-1) ], r ); } if( rtBreak >= 0){ getActiveEdges(true); drawSpan( activeEdge, v[ getVertexNo(rtBreak-1) ], v[ getVertexNo(rtBreak) ], r ); getActiveEdges(false); drawSpan( activeEdge, v[ getVertexNo(rtBreak) ], v[ getVertexNo(rtBreak+1) ], r ); } }//DRAW protected void drawSpan( int[] aE, Vertex2D vStart, Vertex2D vFinish, Raster r) { //System.out.println("IN TRIANGLE.DRAWSPAN......" ); int pix; int aE0 = aE[0]; int aE1 = aE[1]; //System.out.println( " aE0=" + aE0 +" aE1=" + aE1 ); int x, y; y = (int)(vStart.gety()+0.5); int yFinish = (int)(vFinish.gety()+0.5); //System.out.println( " yStart=" + y +" yFinish=" + yFinish ); while( y <= yFinish ) { int xFloor = (int)( -( (edge[aE0].getC()+(edge[aE0].getB() *(float)y) )/ (edge[aE0].getA()) ) + 0.5 ); int xCeil = (int)( -( (edge[aE1].getC()+(edge[aE1].getB() *(float)y) )/ (edge[aE1].getA()) ) ); //System.out.println( " y=" + y +"*************" ); //System.out.println( "xFloor =" + xFloor +"xCeil =" + xCeil ); for( x=xFloor; x<=xCeil; x++ ) { //System.out.println( " x=" + x ); pix = v[0].getargb(); //CHANGE THIS AFTER INTERPOLATION if( (x<120)&&(y>202)&&(y<212)){ System.out.println( "DRAWING THIS UNNECESARYT LINE" ); System.out.println( " x=" + x +" y=" + y + " pix=" + pix ); } r.setPixel( pix, x, y); } y++; } }//DRAWSPAN public boolean isPointInside(float x, float y) { int flag = 0; for( int i=0; i<3; i++ ) { if( edge[i].evaluateAt(x,y)>=0 ) flag+=1; } if( flag==3 ) return true; else return false; } // interface methods public void drawLine( Raster r ){;} public void drawLine( Raster r, float[] alpha, float[] red, float[] green, float[] blue) {;} } // CLASS TRIANGLE2D