QT绘制雷达效果图_qt雷达简易

#define SMOOTH(r,R) (1.0-smoothstep(R-1.0,R+1.0, r))
#define RANGE(a,b,x) ( step(a,x)*(1.0-step(b,x)) )
#define RS(a,b,x) ( smoothstep(a-1.0,a+1.0,x)*(1.0-smoothstep(b-1.0,b+1.0,x)) )
#define M_PI 3.1415926535897932384626433832795

#define blue1 vec3(0.74,0.95,1.00)
#define blue2 vec3(0.87,0.98,1.00)
#define blue3 vec3(0.35,0.76,0.83)
#define blue4 vec3(0.953,0.969,0.89)
#define red   vec3(1.00,0.38,0.227)

#define MOV(a,b,c,d,t) (vec2(a*cos(t)+b*cos(0.1*(t)), c*sin(t)+d*cos(0.1*(t))))

float movingLine(vec2 uv, vec2 center, float radius)
{
    //angle of the line
    float theta0 = 90.0 * iTime;
    vec2 d = uv - center;
    float r = sqrt( dot( d, d ) );
    if(r<radius)
    {
        //compute the distance to the line theta=theta0
        vec2 p = radius*vec2(cos(theta0*M_PI/180.0),
                            -sin(theta0*M_PI/180.0));
        float l = length( d - p*clamp( dot(d,p)/dot(p,p), 0.0, 1.0) );
        d = normalize(d);
        //compute gradient based on angle difference to theta0
            float theta = mod(180.0*atan(d.y,d.x)/M_PI+theta0,360.0);
        float gradient = clamp(1.0-theta/90.0,0.0,1.0