draw method
Implementation
void draw(double percent, double tilt) {
context.blendFunc(WebGL.ONE, WebGL.ONE_MINUS_SRC_ALPHA);
context.clearColor(0, 0, 0, 0);
context.clear(WebGL.COLOR_BUFFER_BIT);
context.viewport(0, 0, textureWidth, textureHeight);
context.useProgram(_programHandle);
context.enableVertexAttribArray(_positionAttr);
context.bindBuffer(WebGL.ARRAY_BUFFER, _posBuffer);
context.vertexAttribPointer(_positionAttr, 3, WebGL.FLOAT, false, 0, 0);
context.enableVertexAttribArray(_texCoordAttr);
context.bindBuffer(WebGL.ARRAY_BUFFER, _uvBuffer);
context.vertexAttribPointer(_texCoordAttr, 2, WebGL.FLOAT, false, 0, 0);
context.activeTexture(WebGL.TEXTURE0);
context.bindTexture(WebGL.TEXTURE_2D, _mainTexture);
context.uniform1i(_textureUniform, 0);
context.uniform1f(_percentUniform, percent);
context.uniform1f(_tiltUniform, tilt);
context.uniform2f(_sizeUniform, _imageWidth, _imageHeight);
context.uniform1f(_rollSizeUniform, rollSize);
context.drawArrays(WebGL.TRIANGLE_STRIP, 0, 4);
}