Comp Form: Week 6

smooth lines, distortion, intersection . . . //Problem 1. Create a function called smoothPath that takes as input an array of points (Vec2d*), the number of points (int), and a smoothing parameter (float) between 0.0 and 1.0. Apply this function to a stroke that has been drawn. Optionally, try applying it to the stroke as it’s being drawn.

//int numPoints=0;
//Vec2d pointList[1000];
Vec2d S[1000];
void smoothPath(float smooth){
	glColor3f(1,0,0);
	//glLineWidth(20);
	glBegin(GL_LINE_STRIP);
	for ( int i=0; i<numpoints;i++){>
		if(i&gt;2){
			Vec2d A=Vec2d(pointList[i-2].x, pointList[i-2].y);
			Vec2d B=Vec2d(pointList[i-1].x, pointList[i-1].y);
			Vec2d C=Vec2d(pointList[i].x, pointList[i].y);

			S[i]=A*(1-smooth)/2+B*smooth+C*(1-smooth)/2;

			glVertex2f(S[i].x,S[i].y);
		}
	}
	glEnd();
}</numpoints;i++){>

//Problem 2. Create a function called distortPath that distorts a shape by pushing its vertices radially away from 10 pre-set points on the screen, each of which should have a different distortion strength. Apply this function to a circle composed of 360 points. Optionally, allow the circle to be dragged about the screen.

void distortPath(Vec2d shape[], int shapeSize, Vec2d distort[], int distortSize){
	glColor3f(1,0,0);
	//glLineWidth(20);

	for ( int k=0; k<distortsize;k++){>
		glRectf(distort[k].x,distort[k].y,distort[k].x+2,distort[k].y+2);
	}

	float distortX[shapeSize];
	float distortY[shapeSize];
	float dist[distortSize];
	Vec2d sd1[distortSize];

	glBegin(GL_LINE_LOOP);

	for ( int i=0; i<shapesize;i++){>
		distortX[i]=0;
		distortY[i]=0;
		for ( int l=0; l<distortsize;l++){>
			sd1[l]=shape[i]-distort[l];
			dist[l]=sd1[l].length()/500;
			sd1[l].normalize();
			distortX[i]+=sd1[l].x/dist[l];
			distortY[i]+=sd1[l].y/dist[l];
		}
		glVertex2f(shape[i].x+distortX[i],shape[i].y+distortY[i]);
	}

	glEnd();
}
</distortsize;l++){></shapesize;i++){></distortsize;k++){>

//Problem 3. Create a function that detects if a drawn stroke intersects itself. If it has, draw a finished shape that uses the intersection point as its start and end point, and is filled in solid red. Call this function continuously while drawing.

bool checkIntersection (Vec2d P0a, Vec2d P0b, Vec2d P1a, Vec2d P1b){
	bool checkIntersection;
	float M0=(P0b.y-P0a.y)/(P0b.x-P0a.x); //slope
	float M1=(P1b.y-P1a.y)/(P1b.x-P1a.x);

	float X=P1a.y-P0a.y-P1a.x*M1+P0a.x*M0;
	X/=(M0-M1);
	float left0=min(P0a.x,P0b.x);
	float right0=max(P0a.x,P0b.x);

	float left1=min(P1a.x,P1b.x);
	float right1=max(P1a.x,P1b.x);

	if(X&gt;left0 &amp;&amp; X<right0>left1 &amp;&amp; X<right1){>
		checkIntersection= true;
	}
	else {
		checkIntersection=false;
	}
	return checkIntersection;
}

void drawStrokeFill(float smooth){
	glColor3f(1,0,0);
	//glLineWidth(20);
	bool intersect;

	glBegin(GL_LINE_STRIP);
	for ( int i=0; i<numpoints;i++){>
		if(i&gt;2){
			Vec2d A=Vec2d(pointList[i-2].x, pointList[i-2].y);
			Vec2d B=Vec2d(pointList[i-1].x, pointList[i-1].y);
			Vec2d C=Vec2d(pointList[i].x, pointList[i].y);

			S[i]=A*(1-smooth)/2+B*smooth+C*(1-smooth)/2;

			glVertex2f(S[i].x,S[i].y);
		}
	}
	glEnd();

	for (int i=1;i<numpoints;i++){>
		for (int j=1;j<numpoints;j++){>
			intersect=	checkIntersection(S[i],S[i-1],S[j],S[j-1]);
			if (intersect==true) {

				glBegin(GL_TRIANGLE_FAN);
				for ( int i=0; i<numpoints;i++){>
					if(i&gt;2){
						Vec2d A=Vec2d(pointList[i-2].x, pointList[i-2].y);
						Vec2d B=Vec2d(pointList[i-1].x, pointList[i-1].y);
						Vec2d C=Vec2d(pointList[i].x, pointList[i].y);

						S[i]=A*(1-smooth)/2+B*smooth+C*(1-smooth)/2;

						glVertex2f(S[i].x,S[i].y);
					}
				}
				glEnd();
			}
		}
	}
}
</numpoints;i++){></numpoints;j++){></numpoints;i++){></numpoints;i++){></right1){></right0>