先看效果圖

同樣使用VS Code安裝glsl-canvas還有Shader Language兩個插件。

圓形掃描.gif

#ifdef GL_ES
precision mediump float;
#endif

uniform sampler2D u_texture_0; //紋理圖片
uniform vec2 u_resolution; //畫布分辨率
uniform float u_time; //時間全局變量，動態(tài)改變
uniform int axis; //旋轉(zhuǎn)軸如：X軸 Y軸 Z軸
uniform sampler2D u_texture_1; //紋理圖片1
uniform sampler2D u_texture_2; //紋理圖片2
uniform sampler2D u_texture_3; //紋理圖片3
uniform sampler2D u_texture_4; //紋理圖片4
uniform sampler2D u_texture_5; //紋理圖片5

void main() {
    vec2 uv0 = gl_FragCoord.xy/u_resolution;
    float direction = 3.0;

    float u_progress = u_time / 1.0;
    vec2 size = u_resolution;
    vec2 uv1 = uv0*size;
    vec2 center = 0.5*size;
    vec2 start = vec2(0.5*size.x,0.0)-center;
    vec2 end = uv1 - center;
    float cos_theta = dot(start,end)/(length(start)*length(end));
    float theta = degrees(acos(cos_theta));
    if(uv0.x>0.5)
    {
        theta = 360.0-theta;
    }
    float angle_threshold = u_progress*360.0;
    if(theta<angle_threshold)
        gl_FragColor = texture2D(u_texture_1,uv0);
    else
        gl_FragColor = texture2D(u_texture_0,uv0);

}