uniform vec2 viewSize;
attribute vec2 vertex;
attribute vec2 tcoord;
varying vec2 ftcoord;
varying vec2 fpos;
void main(void) {
ftcoord = tcoord;
fpos = vertex;
gl_Position = vec4(2.0 * vertex.x / viewSize.x - 1.0, 1.0 - 2.0 * vertex.y / viewSize.y, 0, 1);
}