I adopted a feral from my yard, who lives in my house now and is no longer feral, but very nice,gentle, and friendly.
If you eventually wanted to adopt this cat, what happened is a good start! But you'll need more time before considering to adopt. He'll need to trust you enough that you can pet him without him hissing/biting/scratching.
Sitting down outside being very quiet and still having food by you, if he will eat next to you is something to do every day. Eventually he may decide to rub against you and start to trust you. Once he starts doing that and smelling you, see if he will smell your hand. If he allows you to pet him with no fear, see if he will take bits of food out of your hand. If he will thats a major breakthrough.
Every cat is different, but here is the steps (progress) my cat took before I adopted her.
stage 1. cat came around, would eat food, if she saw me would run away and not come back that day.
stage 2. cat would come by, would eat even though I was looking out my door, but would run away if I went outside.
stage 3. cat came by to eat, started coming by my back door for food, would eat by the door while I sat inside.
stage 4. cat would eat with me outside, but would no approach me.
stage 5. cat would eat, and come 5 feet from me to eat while I sat down, but if I got too close would hiss and growl.
stage 6. cat would come to eat, and eat the food right in front of me, but would still growl/hiss if I tried to pet her.
stage 7. cat would eat by me, I could walk around and it would not phase her, she would no longer hiss or growl at me.
stage 8. cat would come to eat, and rub against me! she then let me pet her! we are starting to become buddies!
stage 9. cat would sit by back door meowing all day and night to eat, and would start to come inside my house if i let her!
stage 10. cat would come inside, let my family pet her, pick her up, would spend all day in my yard without leaving and cry all night for me.
stage 11. we adopted the cat, and she made a great pet and loves being inside.