There are a great number of questions relating to exactly two points in texture coordinates, and my shader already works with that concept. 1.0, 1.0 shows the entire image, and 1.0 / frame in one dimension or another displays the appearance of... well, unfortunately, it displays everything between 0.0 of the quad, to the decimal value of the division of the frame.
What I'd like to do is, from the shader, control all four points of the texture coordinates. In every tutorial and every sample, the texture coordinate vec is always a vec2, implying that you only have control over the two end-points, and not the starting points. Is there a way to eliminate this limitation?
To give you an idea of why I want to do this (If it isn't blatantly obvious already), I'd like to pick a tile or animated frame out of a larger sheet.
Ideally, I'd also be able to find the dimensions (Width and height) of the image in the shader, but if necessary, it isn't that difficult to pass those values in. I believe at this time I'm using GLSL 2, meaning I'm unable to use the textureSize2D function in the shader (Already tried it).
