texRotShader.vert

/* Uniform vars */
uniform float uniformAngle; /* Rotation angle */
uniform vec2 rotationCenter; /* Rotation centre */

/* Attribute vars */
attribute vec2 position; /* Position */
attribute vec2 texCoordIn; /* Texture coordinates */

/* Texture coordinate, used by pixel shader */
varying vec2 texCoord;

/* Main shader function */
void main()
{
    /* Translate UVs to rotation origin, rotate, translate back */
    position = position - rotationCenter;
    position = mat2(cos(uniformAngle), sin(uniformAngle), -sin(uniformAngle), cos(uniformAngle)) * position;
    position = position + rotationCenter;

    /* Set position */
    gl_Position = vec4(position, 0.0, 1.0);

    /* Pass texCoord */
    texCoord = texCoordIn;
}