Loading BMP into an Effect World

[Vexonomer]

Hey there! I'm trying to load the contents of a .bmp into a PF_EffectWorld, and I'm having a hard time figuring out how that would work. I've used this code I found online to load the bitmap, and I think it's working. But, now I'm not sure how to transfer the data over. Any ideas?

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
typedef struct bitmap
{
    unsigned int width, height;
    unsigned char *pixels;
};
struct bitmap* bmp;
void FreeBmp()
{
    if (bmp && bmp->pixels)
    {
        bmp->width = 0;
        bmp->height = 0;
        free(bmp->pixels);
        free(bmp);
        bmp = NULL;
    }
}
bool LoadBmp(const char *filepath)
{
    bmp = NULL;
    FILE *f = fopen(filepath, "rb");
    if (f)
    {
        bmp = malloc(sizeof(bitmap));
        bmp->width = 0;
        bmp->height = 0;
        bmp->pixels = NULL;
        unsigned char info[54] = {0};
        fread(info, sizeof(unsigned char), 54, f);
        bmp->width = *(unsigned int *)&info[18];
        bmp->height = *(unsigned int *)&info[22];
        unsigned int size = ((((bmp->width * bmp->height) + 31) & ~31) / 8) * bmp->height;
        bmp->pixels = malloc(size);
        fread(bmp->pixels, sizeof(unsigned char), size, f);
        fclose(f);
        for(int i = 0; i < size; i += 3)
        {
            unsigned char tmp = bmp->pixels[i];
            bmp->pixels[i] = bmp->pixels[i + 2];
            bmp->pixels[i + 2] = tmp;
        }
        return true;
    }
    return false;
}

[Mylenium]

If you want to do any actual processing, you still have to hand it over to the respective effects handlers or for that matter panel code when using it as an icon or custom UI element. Outside the PF suites and all that it does nothing.

Mylenium

[Vexonomer]

Do you know how I would go about handing the data over? I'm trying to use the .bmp as an effect world. I'm looking for a simple PF_EffectWorld bitmap = loadBMP("/bitmapfile.cmp"); but I know that's probably not possible. I'm just not sure what process I need to go through in order to get that same outcome.

[shachar carmi · Accepted solution]

i see that in your code you have access to the BMP pixel data. (given that code works. i dind't check it)

you can similarly copy the data into an effect world. once the effect world had been allocated, you can access it's pixel data like so:
PF_Pixel *p = world->data + x + y * (world->rowbytes / sizeof(PF_Pixel));

p->red = bmpPixel->red;//whatever the correct syntax of the bmp pixel data is...

p->green= bmpPixel->green;

ect...

note that the order or the RGBA channels in the bmp and in the effect world may not be the same.

also, i've shown the exmaple of copying an 8bit bmp into an 8bit world. that also might not always be the case, so value conversion may be required.

[Vexonomer]

Okay, I think I'm starting to understand. One last question, if that's alright. If I have the RGB data from my .bmp in a vector, like this:

bmpPixel[0]; // Red pixels

bmpPixel[1]; // Green pixels

bmpPixel[2]; // Blue pixels

how can I copy that data into the effect world?

[shachar carmi]

assuming the bmp pixel data is an unsigned char, 0-255, then:

p->red = bmpPixel[0];

p->green = bmpPixel[1];

p->blue = bmpPixel[2];

p->alpha = 255;

[Vexonomer]

Wouldn't that just assign the pixel values to the PF_Pixel and not the PF_EffectWorld? Or am I horribly misunderstanding something?

[shachar carmi]

this line:
PF_Pixel *p = world->data + x + y * (world->rowbytes / sizeof(PF_Pixel));
gets the ram address of a specific pixel in the effect world's buffer. notice that *p is a pointer.

p->red = something;

assings the value to that point in ram, on the red offset for the pixel's address.

[Vexonomer]

Oh my goodness. Yes, I get it now. Thank you for being patient with me on that.