Yes I can write to textures, I do it all the time, but specifically I wanted to recover the post vertex shader coordinates.
The problem is this, I can generate terrain on a planetary scale with a vertex shader, I feed it a vertexbuffer with the x and z coordinates set then generate the y coordinate.
Works fine, but when you want to populate the terrain with things like trees, planets, animals, you end up doing all the calculations again, which is just too slow.
So I implemented a new shader which renders the terrain to a render target which I recover as a texture in vector4 format (on the pc)
The problem is the two do not match up. For some reason I cannot discover they are completly different.
So I tried using pixwin to compare the results of the two shaders, and they are identical.
Which means that the reference graphic driver works, but the graphics driver for my video card does not.
So I don't have a bug in my code, I have a problem with my approach.
IF I can recover the post vertex shader coordinates of my working shader, I can use that directly, or use it to compare with the results of the render to texture to figure out why it isn't working.
Pixwin does it, so there must be a way.