# pedro87

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• Rank
Newbie

• Interests
Art
Design
Education
Programming

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1. ## Painters Algorithm

Thank you for the response, this is what I thought. Again appreciated
2. ## 3D Painters Algorithm

Hi I am looking for some help regarding the Painters Algorithm. I have been reading about it, and everything basically says, its just render things at a distance first and thats all the information that it gives. So I am wondering, does that literally just mean, in code I put in the code to render the background first, then the mid, then the foreground? Or is there actually an algorithm that you feed the objects you want rendered to and somehow it works out the depth of each object? Thank you for any help.
3. ## 3D 3D Graphics Orthographic projection

Hi, I am currently learning 3D graphics using openGL, and I am trying to grasp the different viewing projections. Currently Orthographic. I think i am understanding it, but I just want to be sure, so hoping someone can let me know if I am wrong or not. So what I am trying to figure out is: Does the Orthographic viewing projection matrix get multiplied by each point in the viewing projection box, and that is why z = 0 in the projection matrix, because all the points are being brought to a 2D plane? Initially I thought that Z = 0 did not make sense since the viewing projection box was -1 to 1 in each dimensions, and I thought the matrix had to do with that.But that is wrong, correct?
4. ## calculating normal vectors

Thanks for all the help, finally understand it now. And thanks for the wiki link, I actually had no idea what those symbols were, so that helped a lot.
5. ## calculating normal vectors

It does say that it is not carried out often by game engines but I guess it's just teaching it because...well I'm not sure, just incase I guess. I'm more stuck on what the math is actually saying rather than what it is doing. It is saying the the vector n is found by using the gradient of the ellipsoid at p. Is that what that equation is, the f (p) = x^2 +y^2/4 +z^2 -1 is that the gradient of the ellipsoid at p? And then it gets differentiated? As you can probably tell my math is not at a level which it should be for this.
6. ## calculating normal vectors

I am trying to understand calculating normal vectors in my game engine book. I am having issues understanding a specific section about using gradient to calculate the normal vector. I have attached an image of the page, basically i am unsure where the gradient is coming into play, or just really anything thats going on, on the page. Any help would be appreciated.