QuadCopy.frag

uniform sampler2D uTexColor;

varying vec2 vTexCoord;

void main()
{
  gl_FragColor = texture2D(uTexColor, vTexCoord);
}

QuadCopy.vert

attribute vec2 aPosition;

varying vec2 vTexCoord;

void main()
{
  gl_Position = vec4(aPosition, 0, 1);
  vTexCoord = (aPosition + vec2(1.0)) / 2.0;
}

Vertices.cpp

GLfloat QuadVertices[] =
{
  -1.0, -1.0,
   1.0, -1.0,
   1.0,  1.0,
  -1.0,  1.0
};