Revert "Force non negative value in bloom"

This reverts commit cb922ed4db66a4a9294227ed03af29f34083a59d.
Revert "Fix negative value inside tonemap"

This reverts commit 16dc973faa2e9d6149bb7e6dd6b937ce159e215f.
Revert "Do not allow specvalue to be below 0."

This reverts commit 6b4430caaaf5101ddd45158199e849a0ca930ee9.
Use ifdef WIN32 for test purpose