facefind.cpp

			ofxVec2f vecE, vecF;
		
			double s,t;
			float Ax, Ay, Bx, By, Cx, Cy, Dx, Dy;
			
			bool found = false;
		
			for (int i=0; i<4; i++) {
				Ax = objCorners->at(i)->x;
				Ay = objCorners->at(i)->y;
				
				if(i == 3){
					Bx = objCorners->at(0)->x;
					By = objCorners->at(0)->y;
				} else {
					Bx = objCorners->at(i+1)->x;
					By = objCorners->at(i+1)->y;
				}

				// E = B-A = ( Bx-Ax, By-Ay )
				
				vecE.set(Bx - Ax, By - Ay);
				
				for(int j=0; j<4; j++){
					Cx = cornersAbs[j]->x;
					Cy = cornersAbs[j]->y;
	
					if(j == 3){
						Dx = cornersAbs[0]->x;
						Dy = cornersAbs[0]->y;
					} else {
						Dx = cornersAbs[j+1]->x;
						Dy = cornersAbs[j+1]->y;
					}
					
					// F = D-C = ( Dx-Cx, Dy-Cy )
					vecF.set(Dx - Cx, Dy - Cy);

					s = (-vecE.y * (Ax - Cx) + vecE.x * (Ay - Cy)) / (-vecF.x * vecE.y + vecE.x * vecF.y);
					t = ( vecF.x * (Ay - Cy) - vecF.y * (Ax - Cx)) / (-vecF.x * vecE.y + vecE.x * vecF.y);
					
					if (s >= 0 && s <= 1 && t >= 0 && t <= 1){
						printf("h: %f <%f, %f> - ", h, vecE.x, vecE.y);
						// found intersecting face
						vecE.normalize();						
						vecE.set(-1*vecE.y, vecE.x);
						vecE *= 0.25f;
						printf("<%f, %f>\n", vecE.x, vecE.y);
						
						pos.set(pos.x - vecE.x, pos.y - vecE.y);
						pos -= vel;
						vel.set(0.0, 0.0);
						brake();
						found = true;
						break;
					}
					
				}
				
				if(found){
					break;
				}
			}