Question

我想使用渐变色绘制曲线，如图

这是我的曲线绘制代码，但此代码仅适用于一种颜色。

public class Test extends ApplicationAdapter{

//create paths
private Bezier<Vector2> path1; 
private ShapeRenderer sr;

@Override
public void create () {

    // set up random control points
    int width = Gdx.graphics.getWidth();
    int height = Gdx.graphics.getHeight();
    int points = 4;
    Vector2[] controlPoints = new Vector2[points];
    for (int i = 0; i < points; i++) {
       int x = (int) (Math.random() * width) ;
       int y = (int) (Math.random() * height);
       Vector2 point = new Vector2(x, y);
       controlPoints[i] = point;
    }


    path1 = new Bezier<Vector2>(controlPoints);


    sr = new ShapeRenderer();
    sr.setAutoShapeType(true);
}




@Override
public void render () {
    Gdx.gl.glClearColor(0f, 0f, 0f, 0f);
    Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);

    sr.begin();
    sr.setColor(Color.WHITE);

    //draw path1
    for(int i = 0; i < 100; ++i){
        float t = i /100f;
        // create vectors to store start and end points of this section of the curve
        Vector2 st = new Vector2();
        Vector2 end = new Vector2();
        // get the start point of this curve section
        path1.valueAt(st,t);
        // get the next start point(this point's end)
        path1.valueAt(end, t-0.01f);
        // draw the curve
        sr.line(st.x, st.y, end.x, end.y);

    }



    sr.end();
}

@Override
public void dispose () {
}

}

我可以通过以下两种方法使用渐变色绘制一个矩形和一条线

shapeRenderer.filledRect(x, y, width, height, lightBlue, lightBlue, darkBlue, darkBlue);

和

shapeRenderer.line(x, y, x2, y2, Color.RED, Color.GREEN);

但是我需要使用渐变色绘制曲线，我已经搜索了很多并且还没有找到任何解决方案。

所以请帮助我。

Answer 1

您可以使用开始和结束颜色之间的线性插值为每个部分找到颜色。像这样：

Color color = new Color();

@Override
public void render() {
    Gdx.gl.glClearColor(0f, 0f, 0f, 0f);
    Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);

    sr.begin();

    Color startColor = Color.YELLOW;
    Color endColor = Color.RED;

    //draw path1
    for (int i = 0; i < 100; ++i) {
        float t = i / 100f;
        //interpolate linearly between start and end colors
        sr.setColor(color
                .set(startColor)
                .lerp(endColor, t)
        );
        // create vectors to store start and end points of this section of the curve
        Vector2 st = new Vector2();
        Vector2 end = new Vector2();
        // get the start point of this curve section
        path1.valueAt(st, t);
        // get the next start point(this point's end)
        path1.valueAt(end, t - 0.01f);
        // draw the curve
        sr.line(st.x, st.y, end.x, end.y);
    }

    sr.end();
}

如何在libgdx java中使用渐变颜色绘制曲线

1 个答案: