Add support for floating point textures to OpenGL

Created by: AmnonOwed

I'm packing data in a texture (PImage) to send to a fragment shader. I'm running into the limitations of the 32bit RGBA format that seems to be the default for every texture in Processing. It's causing banding effects in my output. Switching to floating point textures will most likely solve these problems, because of the increased accuracy.

I have searched high and low (all the forums, the source code, the issue list), but I cannot find a way to use floating points textures in Processing. Is this possible? If not, I would like to post this issue as a feature request.

首先追踪 Processing 的 PImage 纹理是如何创建的，以及如何通过其 OpenGL 路径传递给片段着色器。确定需要覆盖哪些浮点纹理格式以及受支持硬件的限制。具备一种有文档记录且经过测试的方法，可以在不受当前 32-bit RGBA 限制的情况下使用浮点纹理，即可视为完成。