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I have read around on this, including Nehe and here for solutions, but I cant find a specific answer.
I am trying to load a a photo, called stars.jpg. I want to make this my background of the scene, by mapping it using uv coordinates, doing it by
glBegin(GL_QUADS);
glTexCoord2f(0,0);
glVertex2f(0,0);
However I am just very confused about how to load the actual textures in, all the calls for
glActiveTexture();
glEnable(GL_TEXTURE_2d);
glBindTexture(GL_TEXTURE);
All they do is confuse me, what do all these mean/do, and in what order am I suppose to put these in, in order to get the stars.jpg to be my background?
272
You need to bind the texture, enable texturing (fixed function pipeline) or use a shader that does texturing (shader pipeline), and draw some shape like a quad. Don't forget the shape you draw needs texture coordinates.
Texture coordinates do not depend on resolution but can be any floating point value, thus OpenGL has to figure out which texture pixel (also known as a texel ) to map the texture coordinate to. This becomes especially important if you have a very large object and a low resolution texture.
A texture is an OpenGL Object that contains one or more images that all have the same image format. A texture can be used in two ways: it can be the source of a texture access from a Shader, or it can be used as a render target.
A sampler2D is used to do lookup in a standard texture image; a samplerCube is used to do lookup in a cubemap texture (Subsection 5.3. 4). The value of a sampler variable is a reference to a texture unit. The value tells which texture unit is invoked when the sampler variable is used to do texture lookup.
Your number-one tool for loading textures in OpenGL is the Simple OpenGL Image Loader (SOIL) library. You just need to pass the filename and some flags and you'll get your texture ID.
Also, you're learning very old and outdated version of OpenGL now - you might want to have a google for newer tutorials or browse the specs whenever you feel ready.
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