Thread: changing color in OpenGL

  1. #1
    Registered User
    Join Date
    Jun 2003

    changing color in OpenGL

    Hi, I want to design a function so if the user press "c" at any time during my program, this function will display random color on the object from green, yellow, blue and red. How do I do it? thanks in advance.
    'The bigger they are, the harder they fall' ~Yang

  2. #2
    Join Date
    Jan 2003
    Okay, so you want to change the red green and blue color components. You've got to generate a floating point between 0 and 1 if you're using glColor3f, which I have to assume that you are because you did not tell me otherwise.

    if(GetKeyState('C') & 0x80)
    red = (float)rand() / (float)RAND_MAX;
    green = (float)rand() / (float)RAND_MAX;
    blue = (float)rand() / (float)RAND_MAX;

    rand() produces a maximum value of rand_max, which is why rand()/ rand_max must produce a float between 0 and 1

    make sure that you call:
    at the start of the program. this 'initializes' the random number generator. include windows.h to get it to work.

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