hi. i'm testing v4. and i create custom shader   
	sprite is created by texture size is using 628x572; 
	and filterArea is set automatically to 1024, 1024;  
	so i can't calculate correct vTextureCoord.
 
	because  end of vTextureCoord looks like 1024, 1024 if vtextureCoord has (1.0, 1.0);  
	how can i calcaulte or get  correct uv.   
	following code is custom shader code
 
function createShaderShadow(x, y, dist) {
// smoke shader
    var uniforms = {};
    uniforms.time = {
        type: