Playing with OpenGL

Just learning the basics of OpenGL for a class and was looking 开发者_JAVA技巧for something challenging and interesting to try and draw. Any suggestions?

Aiming to photorealism (just plain models, lights, materials, textures, etc.) is one thing, but what is even more interesting in my opinion is demoscene and all kinds of non-photorealistic effects. The idea of a demo is to program some nice animated graphics that automatically change from one effect to another or tell some sort of a story, and have a background music. Here you can find some videos. Just take a look at what some others have done and use your imagination. That's the funniest part of 3D programming in my opinion. Of course what you'll first program would be something extremely simple when compared to those videos on youtube, but everyone has to start from somewhere. Simple also doesn't need to be ugly. Some random suggestions:

• mathematical shapes with sin(), cos(), etc.
• alpha blending, especially addition blending (glBlendFunc(GL_ONE, GL_ONE);)
• terrain rendering
• read 3d model data from a file. (Wavefront .OBJ is a relatively simple one)
• feedback effects with glCopyTexImage2D, which copies pixels from screen to a texture (in real life you shouldn't use this because it's too slow, but when learning the basics it's ok)
• etc...

You might consider building an OBJ viewer. You will get the experience you're looking for, and it's a pretty good project for a beginning 3D graphics programmer, in terms of difficulty.

I believe opengl has built in shapes such as a teapot that you can call and have it draw. For starters, I'd stick with easy shapes like squares, circles, and cones. Try drawing a wireframe model first since that's the easiest, by using either quadstrips ,triangles or just poly lines. After you've gotten that down, learn to set up lighting and materials so you can draw a solid model.

At school we had a very interesting assignement to get started with OpenGL that I will share. The long term goal was to modelize a living room so you basically have to draw:

• A table.
• Two chairs.
• A carpet.
• A sofa
• Some stuff that you might find interesting to add on the table for instance a TV!

When you have all the things done, try to polish the scene a little bit by adding some lighting effects!

Hint: for all the objects you simply need to start with a basic rectangle. Then you can construct your scene step by step using translations/rotations.