good day to all opengl people!!
i have some trouble with a program…
i would like to know how can i read from a “coulour buffer” of the screen the color of a xy pixel in the graphical windows that i create with glut.
i would like to move cursor on that with window with arrows key but the problem is that i dont know how to do for to stop the cursor if he “hit” one segment of the path that he still walked. so i thunk i could “read” from the window the colour of the xy position of the cursor and determinate if that is a path segment (that i colour red) or free place to walk on (that is black). I dont want to save each step of the cursor because that would result the program very slowly, so if u can help me fisrt of all excuse my english my mother speak is italian… thanky oyu all and good programming day!!!
When you talk about walking, the cursor?
Do you want to do like a paint function?
Or like create a map that a player in a game follows and mark were he can and can not walk?
Originally posted by Mad_Musician:
[b]good day to all opengl people!!
i have some trouble with a program…
i would like to know how can i read from a “coulour buffer” of the screen the color of a xy pixel in the graphical windows that i create with glut.
i would like to move cursor on that with window with arrows key but the problem is that i dont know how to do for to stop the cursor if he “hit” one segment of the path that he still walked. so i thunk i could “read” from the window the colour of the xy position of the cursor and determinate if that is a path segment (that i colour red) or free place to walk on (that is black). I dont want to save each step of the cursor because that would result the program very slowly, so if u can help me fisrt of all excuse my english my mother speak is italian… thanky oyu all and good programming day!!!
[/b]
Use glReadPixels to read back. Make sure you read the correct buffer glReadBuffer may be required (probably not but check your results).
Hi opengl people!! thank you fisrt of all for ur interess in my question.
I will try to be more understandable.
I have a cursor that i can move on a window of opengl. That cursor draw a red path along the way he “walk”. My problem is that i want to make impossible for the “player” to move the cursor on a path segment he still “walked”, like it was a wall. Now i m understanding i have to recognize where the wall is. My question is can i read from the colour of the pixel in the window if there is a wall or not. In few words i would like to read the colour of a pixel in the opengl window without save in a array each pixel i have drawn before. I know there is a buffer as the depth buffer from where u can read the information of a pixel with a function (i think glReadPixel but i didnt it before and the tutorials i did read are too difficult for me. If u were so gently to wrote me a little example that were beautifull!!!
I would need something like
colorofxypixel = glreadthecolorofxypixel
but i dont know how to dooooo
i use glut and opengl libraries i did study a little c and c++ but not win32 or such things like mfc and co…
(my target were to program a little wolfied game because in that i have i cannot save my play…)
So thank u all and good programming day!!
byeeeeeee