【Defold】指定したピクセルの色を入れ替える「change 1 color」シェーダー

attribute highp vec4 position;
attribute mediump vec2 texcoord0;
attribute mediump vec3 normal;
uniform mediump mat4 mtx_worldview;
uniform mediump mat4 mtx_view;
uniform mediump mat4 mtx_proj;
uniform mediump mat4 mtx_normal;
varying highp vec4 var_position;
varying mediump vec3 var_normal;
varying mediump vec2 var_texcoord0;
void main()
{
    vec4 p = mtx_worldview * vec4(position.xyz, 1.0);
    var_position = p;
    var_texcoord0 = texcoord0;
    var_normal = normalize((mtx_normal * vec4(normal, 0.0)).xyz);
    gl_Position = mtx_proj * p;
}

varying highp vec4 var_position;
varying mediump vec3 var_normal;
varying mediump vec2 var_texcoord0;
 
uniform lowp sampler2D tex0;
uniform lowp vec4 tint;
uniform lowp vec4 _ColorChangeTolerance;
uniform lowp vec4 _ColorChangeTarget;
uniform lowp vec4 _ColorChangeNewCol;
uniform lowp vec4 _ColorChangeLuminosity;
 
float saturate(float f)
{
    return clamp(f,0.0,1.0);
}
 
void main()
{
    vec4 tint_pm = vec4(tint.xyz * tint.w, tint.w);
    vec4 col = texture2D(tex0, var_texcoord0.xy) * tint_pm;
 
    float luminance = 0.3 * col.x + 0.59 * col.y + 0.11 * col.z;
    luminance = saturate(luminance + _ColorChangeLuminosity.w);
    vec3 dif = abs(col.xyz - _ColorChangeTarget.xyz);
    col.xyz = mix(col.xyz, vec3(luminance, luminance, luminance) * _ColorChangeNewCol.xyz,
    max(sign(1.0 - saturate(dif.x + dif.y + dif.z) - _ColorChangeTolerance.w), 0.0));
 
    gl_FragColor = col;
}