How do I calculate what was made in TX vs CA on my W-2s

If you worked for the same employer in Texas and California and they changed your state withholding from none (because you were in Texas) to California,  Your California earnings will be reported on the W-2, and your Texas earnings will be the total less the California amount.   

If your company didn't change your state when you relocated, use your payroll information.  If you don't receive paycheck details each pay period via mail, you would have access to them online, either on your employer's website or on the payroll provider's website.  Review your payroll information to see which pay period was worked entirely in Texas.  If the next pay period included both Texas and California, then calculate how much was earned while working in Texas.  Add that to your Year to Date total on the last pay period worked entirely in Texas and that is your Texas income.  California is the total less Texas.