CODEWITHSUNDEEP
copengl
Iceman
Iceman

Reputation: 4372

Normalize glTranslatef()

The arguments to glTranslate() specify the amount of units by which the origin is translated. Hence, there is a possibility of moving beyond the display. Is there a way to normalize the amount we move so that we don't go beyond the drawing area?

Upvotes: 0

Views: 412

Answers (1)

Nicol Bolas
Nicol Bolas

Reputation: 474086

The arguments to glTranslate() specify the amount of units by which the origin is translated.

No (yet another reason people should stop learning fixed-function GL).

glTranslate generates a matrix, which is right-multiplied by the current matrix to become the new current matrix. It does create a translation matrix, but it's not necessarily moving from the center of the screen. For example, this is perfectly valid:

glTranslatef(10.0f, 10.0f, 10.0f);
glTranslatef(0.0f, 50.0f, 0.0f);

It's also valid to do this:

glTranslatef(10.0f, 10.0f, 10.0f);
glRotatef(90.0f, 0.0f, 0.0f, 1.0f);
glTranslatef(0.0f, 50.0f, 0.0f);

This does a translation, then a 90-degree rotation about the Z axis. This affects the final translation performed.

You could also throw a scale in there.

If you want to keep an object on-screen, it's up to you, not OpenGL.

Upvotes: 6

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