3D graphics questions that do not deserve their own thread (OpenGL / Dx10)

The Something Awful Forums > Discussion > Serious Hardware/Software Crap > The Cavern of COBOL > 3D graphics questions that do not deserve their own thread (OpenGL / Dx10)

magicalblender: Sep 29, 2007

What's better, drawing pixels directly, or using textures? Poking around the OpenGL documentation, I see that I can put pixel data into a raster and glDrawPixels() it onto the screen. I can also put the pixel data onto a texture, put the texture on a quad, and put that onto the screen. If I'm just doing two-dimensional imaging, then which is preferable?

Also, am I crazy, or has the page for glutKeyboardUpFunc disappeared from the Opengl documentation? I could swear I was looking at it a couple weeks ago, but it isn't there now.

# ¿ Oct 1, 2008 23:52

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magicalblender: Sep 29, 2007

Luminous posted:

I have two points, which can be used to make some vector leading from one point to the other. I simply want to place my camera such that it is positioned at one of the points (easy!) and looking along the vector path (I thought it was easy?!).

What I need in terms of the rotation to look down the vector path is HPR (heading, pitch, roll).

heading and pitch are pretty simple to find with some trigonometry.

code:

hypotenuse = sqrt(dx*dx + dz*dz);
heading = atan2(dz, dx);
pitch = atan2(dy, hypotenuse);

Return values for atan2() are in the range [-pi, pi] so you may need to convert accordingly to your favorite angle measurement system.

Not sure how you'd find roll. Surely you'd need a separate "up" vector, but I forget what you do with it.

Sorry if this isn't what you're asking for. I don't know much about matrices, so that part of your question went over my head :saddowns:

# ¿ Aug 11, 2009 16:50

The Something Awful Forums > Discussion > Serious Hardware/Software Crap > The Cavern of COBOL > 3D graphics questions that do not deserve their own thread (OpenGL / Dx10)