closer is slower ?

Ghoti · Post by **Ghoti** » Sun Dec 24, 2006 4:11 am

Hi folks,

I have this small part of a level that i render. It is about 50 triangles and textured with one 512 x512 texture.
I have also a box made from 12 triangles textured with a texture of 256x256 (which i can easily downgrade and i will but i always start big to get the best resulting graphics i can have.
I have 5 of these boxes in this levelpart.

the problem is that when i am close enough so that only a very small part of the level triangles are in view and all the boxes are in view the movement gets a lot slower. However when i move backwards with still all the boxes in view and with each step backward more of the level is visible and the speed increases. To my knowledge this is very strange behaviour :S i hope someone can help me understand what is the matter with my program.

(i have not connect movement to fps yet because i wanted to see if some levelparts are slower then the other and i have not yet implemented fps counter.)

greets ghoti

siberianstar · Post by **siberianstar** » Sun Dec 24, 2006 8:09 am

never heard about mipmapping ?

Ghoti · Post by **Ghoti** » Sun Dec 24, 2006 8:09 pm

if i am not mistaken, mipmapping is multiple textures for one object, so the farther away less detailed textures right?

my problem is the other way around. The farther away the quicker the my code runs. no changes in textures or level of detail.

ufoz · Post by **ufoz** » Sun Dec 24, 2006 8:46 pm

Fillrate?

Ghoti · Post by **Ghoti** » Sun Dec 24, 2006 8:48 pm

http://en.wikipedia.org/wiki/Fillrate <---- is this what you mean? and do i have control over this?

siberianstar · Post by **siberianstar** » Sun Dec 24, 2006 9:20 pm

Your problem is that you have to mipmap your textures

Tomaz · Post by **Tomaz** » Sun Dec 24, 2006 9:29 pm

siberianstar wrote:Your problem is that you have to mipmap your textures

Mipmapping makes the PSP use a lower resolution copy of the image when the surface gets further away. Mipmapping shouldnt do anything on a surface thats close up.

Ghoti · Post by **Ghoti** » Sun Dec 24, 2006 9:37 pm

hmmm i have read this: http://en.wikipedia.org/wiki/Mipmap

it states that i have to make multiple texture of smaller sizes and interpolate between them, however is it not simpler to just take the smaller one or the bigger one instead of calculating averages of textures?

and the main problem is how do i implement this on the psp? any tutorials or pointers to get me started?

i have changed the texture to a 128x128 texture and i had no longer the problem. So i guess the psp can't handle many large textures in one screen.

siberianstar · Post by **siberianstar** » Sun Dec 24, 2006 9:39 pm

Mipmapping makes the PSP use a lower resolution copy of the image when the surface gets further away. Mipmapping shouldnt do anything on a surface thats close up.

This is wrong. Mipmapping is used also when the uvs texture coordinates are closer and does not cover all the texture.

Gothi: If you mipmap the textures PSP can handle them.