Vermes
Advanced Member level 4
In this project, microcontroller reads the models in OBJ format directly from memory card RS-MMC or SD card. The whole device acts as an OBJ models minibrowser.
A selected model after loading is scaled into the size of the window. That prevents the model from leaving outside the screen or displaying the model of few pixels.
Then the program determines the center of the model. After that a rotation can be made.
Sometimes the reference point (pivot) is outside the model, which makes the model orbits during the rotation. Matching a new reference point in the center of the model allows it to eliminate.
To draw lines, Bresenham algorithm implementation was used. The project supports objects with up to 1000 vertices.
Hardware
- all is powered by Atmega128 and clocked 16MHz
- the display resolution is 240x128. It has a Toshiba T6963C driver
- RAM memory has 128KB 55ns + 74HC573 (only 64KB is used)
- memory card reader is driven by software SPI
Assumptions
- supports memory cards
- support for the file system
- support for external RAM
- interpretation of OBJ files
- reading and rewriting the coordinates for each vertex arrays
- read and write the vertices making up the next wall
Link to original thread – ATmega128 - przeglądarka modeli 3D