Shader-Radar 着色器案例详解（1）
#define mix lerp
#define vec2 float2
#define vec3 float3
#define vec float
#define vec4 float4
#define iTime View.RealTime
#define mod fmod
#define fract frac
#define atan atan2
#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))))
struct radar {
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);
return SMOOTH(l,1.0)+0.5*gradient;
}
else return 0.0;
}
float circle(vec2 uv, vec2 center, float radius, float width)
{
float r = length(uv - center);
return SMOOTH(r-width/2.0,radius)-SMOOTH(r+width/2.0,radius);
}
float circle2(vec2 uv, vec2 center, float radius, float width, float opening)
{
vec2 d = uv - center;
float r = sqrt( dot( d, d ) );
d = normalize(d);
if( abs(d.y) > opening )
return SMOOTH(r-width/2.0,radius)-SMOOTH(r+width/2.0,radius);
else
return 0.0;
}
float circle3(vec2 uv, vec2 center, float radius, float width)
{
vec2 d = uv - center;
float r = sqrt( dot( d, d ) );
d = normalize(d);
float theta = 180.0*(atan(d.y,d.x)/M_PI); //glsl的atan范围在-90~90，而 Hlsl的取值范围-180~180
return smoothstep(2.0, 2.1, abs(mod(abs(theta)+2.0,45.0)-2.0)) * //-135对应 45
mix( 0.5, 1.0, step(45.0, abs(mod(theta, 180.0)-90.0)) ) *
(SMOOTH(r-width/2.0,radius)-SMOOTH(r+width/2.0,radius));
}
float triangles(vec2 uv, vec2 center, float radius)
{
vec2 d = uv - center;
return RS(-8.0, 0.0, d.x-radius) * (1.0-smoothstep( 7.0+d.x-radius,9.0+d.x-radius, abs(d.y)))
+ RS( 0.0, 8.0, d.x+radius) * (1.0-smoothstep( 7.0-d.x-radius,9.0-d.x-radius, abs(d.y)))
+ RS(-8.0, 0.0, d.y-radius) * (1.0-smoothstep( 7.0+d.y-radius,9.0+d.y-radius, abs(d.x)))
+ RS( 0.0, 8.0, d.y+radius) * (1.0-smoothstep( 7.0-d.y-radius,9.0-d.y-radius, abs(d.x)));
}
float _cross(vec2 uv, vec2 center, float radius)
{
vec2 d = uv - center;
int x = int(d.x);
int y = int(d.y);
float r = sqrt( dot( d, d ) );
if( (r<radius) && ( (x==y) || (x==-y) ) )
return 1.0;
else return 0.0;
}
float dots(vec2 uv, vec2 center, float radius)
{
vec2 d = uv - center;
float r = sqrt( dot( d, d ) );
if( r <= 2.5 )
return 1.0;
if( ( r<= radius) && ( (abs(d.y+0.5)<=1.0) && ( mod(d.x+1.0, 50.0) < 2.0 ) ) )
return 1.0;
else if ( (abs(d.y+0.5)<=1.0) && ( r >= 50.0 ) && ( r < 115.0 ) )
return 0.5;
else
return 0.0;
}
float bip1(vec2 uv, vec2 center)
{
return SMOOTH(length(uv - center),3.0);
}
float bip2(vec2 uv, vec2 center)
{
float r = length(uv - center);
float R = 8.0+mod(87.0*iTime, 80.0);
return (0.5-0.5*cos(30.0*iTime)) * SMOOTH(r,5.0)
+ SMOOTH(6.0,r)-SMOOTH(8.0,r)
+ smoothstep(max(8.0,R-20.0),R,r)-SMOOTH(R,r);
}
};
radar ra;
vec3 finalColor={0.0,0.0,0.0};
vec2 uv = uv_UE;
//center of the image
vec2 c = Screen_size/2.0;
float cross = 0.3*ra._cross(uv, c, 240.0);
finalColor = vec3( cross, cross, cross );
finalColor += ( ra.circle(uv, c, 100.0, 1.0)
+ ra.circle(uv, c, 165.0, 1.0) ) * blue1;
finalColor += (ra.circle(uv, c, 240.0, 2.0) );//+ dots(uv,c,240.0)) * blue4;
finalColor += ra.circle3(uv, c, 313.0, 4.0) * blue1;
finalColor += ra.triangles(uv, c, 315.0 + 30.0*sin(iTime)) * blue2;
finalColor += ra.movingLine(uv, c, 240.0) * blue3;
finalColor += ra.circle(uv, c, 10.0, 1.0) * blue3;
finalColor += 0.7 * ra.circle2(uv, c, 262.0, 1.0, 0.5+0.2*cos(iTime)) * blue3;
if( length(uv-c) < 240.0 )
{
//animate some bips with random movements
vec2 p = 130.0*MOV(1.3,1.0,1.0,1.4,3.0+0.1*iTime);
finalColor += ra.bip1(uv, c+p) * vec3(1,1,1);
p = 130.0*MOV(0.9,-1.1,1.7,0.8,-2.0+sin(0.1*iTime)+0.15*iTime);
finalColor += ra.bip1(uv, c+p) * vec3(1,1,1);
p = 50.0*MOV(1.54,1.7,1.37,1.8,sin(0.1*iTime+7.0)+0.2*iTime);
finalColor += ra.bip2(uv,c+p) * red;
}
return vec4( finalColor, 1.0 );
