let vs_customTexture = {|
precision mediump float;

attribute vec2 a_position;
attribute vec3 a_color;
attribute vec2 a_texCoord;

uniform mat4 u_projectionMat;

varying vec3 v_color;
varying vec2 v_texCoord;

void main() {
  gl_Position = u_projectionMat * vec4(a_position, 0, 1);
  v_color = a_color;
  v_texCoord = a_texCoord;
}
    |};

let fs_customTexture = {|
precision mediump float;

varying vec3 v_color;
varying vec2 v_texCoord;

uniform sampler2D u_sampler2D;

void main() {
  vec4 sample = texture2D(u_sampler2D, v_texCoord);

  gl_FragColor = vec4(v_color * sample.xyz, sample.w);
}
    |};

let vs_fontTexture = {|
precision mediump float;

attribute vec2 a_position;
attribute vec3 a_color;
attribute vec2 a_texCoord;

uniform mat4 u_projectionMat;

varying vec3 v_color;
varying vec2 v_texCoord;

void main() {
  gl_Position = u_projectionMat * vec4(a_position, 0, 1);
  v_color = a_color;
  v_texCoord = a_texCoord;
}
    |};

let fs_fontTexture = {|
precision mediump float;

varying vec3 v_color;
varying vec2 v_texCoord;

uniform sampler2D u_sampler2D;

void main() {
  vec4 sample = texture2D(u_sampler2D, v_texCoord);

  gl_FragColor = vec4(v_color * sample.xyz, sample.w);
}
    |};

let vs_noTexture = {|
precision mediump float;

attribute vec2 a_position;
attribute vec3 a_color;

uniform mat4 u_projectionMat;

varying vec3 v_color;

void main() {
  gl_Position = u_projectionMat * vec4(a_position, 0, 1);
  v_color = a_color;
}
    |};

let fs_noTexture = {|
precision mediump float;

varying vec3 v_color;

void main() {
  gl_FragColor = vec4(v_color, 1.0);
}
    |};