是什么导致这种边缘撕裂？

Question

是什么导致这种GLSL撕裂？在东京的teamLab艺术展览中，我注意到了同样的事情。注意边缘的瑕疵。

这是我的片段着色器：

#version 300 es
precision highp float;
precision highp int;

uniform float time;

in vec2 v_pos;

out vec4 FragColor;

vec4 measureFloat(float measure_number_float){
    return vec4(
        float( mod ( measure_number_float, 60.0 ) ) / 60.0,
        float( mod ( measure_number_float, 3600.0 ) ) / (60.0 * 60.0),
        float( mod ( measure_number_float, 216000.0 ) ) / (60.0 * 60.0 * 60.0),
        1.0
    );
}

vec4 measureInt( int measure_number_int ){
    return vec4(
        float( measure_number_int % 60 ) / 60.0,
        float( measure_number_int % 3600 ) / (60.0 * 60.0),
        float( measure_number_int % 216000 ) / (60.0 * 60.0 * 60.0),
        1.0
    );
}

vec4 sampleColor(){

    int x_coord_i, y_coord_i = 0;
    float x_coord_f, y_coord_f = 0.0;

    float res_mul_x_f = 20.0; // mul = multiplier
    float res_mul_y_f = 20.0; // mul = multiplier

    x_coord_i = int(v_pos.x * res_mul_x_f);
    y_coord_i = int(v_pos.y * res_mul_y_f);

    // return back to float:
    x_coord_f = float(x_coord_i) / res_mul_x_f;
    y_coord_f = float(y_coord_i) / res_mul_y_f;

    int cell_number = y_coord_i * int(res_mul_x_f) + x_coord_i;

    // return measureInt(cell_number);
    return measureFloat(float(cell_number));

}

void main(void) {

    FragColor = sampleColor();

}

使用measureInt函数和measureFloat函数，Chrome和Firefox中均存在此错误。我也不知道该怎么称呼，因此，如果有专门的名称，请告知。