I'm trying to implement a sprite animation on a microcontroller like ARM Cortex M4.

I can now draw a bitmap.. the bitmap is stored on eeprom or static memory as an array.. 

Now my plan is to load a sprite sheet, then try animate the sprite...

What is the easiest approach for that purpose ?

Would someone recommend resources like books or tutorials on old school bitmapped graphics programming ?

That sounds like a fun project! I've loved to program software rasterizer on arm!

What is your exact hardware?

What exactly do you want to program? A lot of old school tutorials teach about using special hardware to handle sprites, e.g. gameboy.

But on the other side,everything with sprites is quite straight forward.maybe ask for something specific we can help on

My hardware is STMF32 Discovery board 429

I'm trying to crop an image (bitmap) static array, I get scan lines

I made grap x,y 0,0

its hould draw the whole image, but it draws scanlines

void Rasterizer::GrapBitmap(uint16_t *bitmap, sprite_ptr sprite, int sprite_frame, int grap_x, int grap_y)
{
    sprite->frames[sprite_frame] = (uint16_t*)malloc(sprite->width*sprite->height*2);

    uint16_t *sprite_data = sprite->frames[sprite_frame];

    for (size_t row = 0; row < sprite->width; row++)
    {
        for (size_t col = 0; col < sprite->height; col++)
        {
            sprite_data[row*sprite->width  + col] = bitmap[((row + grap_y)*sprite->width) + (grap_x) + col];
        }
    }
}

void Rasterizer::DrawSprite(sprite_ptr sprite)
{
    int i, j;

    for (i = 0; i < sprite->width; i++)
        for (j = 0; j < sprite->height; j++) {
            int width = sprite->width;
             uint16_t *work = sprite->frames[sprite->curr_frame];
             uint16_t color = work[j*sprite->width + i];
            SetPixel(i + sprite->x, j + sprite->y, color);
         }
}

Well, it seems like you're iterating "row" from 0 to width, and not from 0 to height... and the converse mistake with "col". Unless your graphics data and screen buffer are column-major, and you're deliberately rendering rotated 90 degrees from the screen's natural orientation?

If you're on a tiny microcontroller like this, why are you burning RAM by copying image data from one "bitmap" area in EEPROM to many "sprite" areas the RAM heap at runtime? Is EEPROM access significantly slower than RAM access on this platform?

In your DrawSprite method, you only need to calculate the *work pointer once per method call, not once per pixel.

And last, if that processor has any kind of CPU cache and cache lines are wider than a UINT16, you will very likely get much better performance if you make Y coordinates your outer loop; currently it's your inner loop.

Thanks for your comments, I will keep that thread as update to the progress.

Right now I'm doing the stuff on the SDL as a simulator to the C code that is going to be ported on ARM until I get the kit.

@dave j

@Wyrframe

I'm doing bitmapped graphics and eats up the memory... for example a frame of animation takes 10k bytes, 70*70*2 (16bits)..

any suggestions for reducing memory consumption ?

Progress:

You need external EPROM to store the bitmaps.