Setting VBE modes with GRUB2

[abcdef4bfd]

Read this carefully.

Readed, but how to get pixelwidth? In VBE Mode Info structure there's no this entry.

[BrightLight]

The VBE mode information structure contains the width in pixels, height in pixels, bitdepth in bits, which should be 1024x768x32 as it is what you're using. The pitch means bytes per line. You need to use that as well. My GitHub repository has some graphical code in kernel/gdi.asm and kernel/vesa.asm. It's in assembly language, but shouldn't be too hard to convert to C.
EDIT: Forgot to say this, "pixelwidth" is just "bitdepth/8".

[abcdef4bfd]

The VBE mode information structure contains the width in pixels, height in pixels, bitdepth in bits, which should be 1024x768x32 as it is what you're using. The pitch means bytes per line. You need to use that as well. My GitHub repository has some graphical code in kernel/gdi.asm and kernel/vesa.asm. It's in assembly language, but shouldn't be too hard to convert to C.
EDIT: Forgot to say this, "pixelwidth" is just "bitdepth/8".

I don't know assembly memory access, so what I should do?

[glauxosdever]

Hi,

The VBE mode information structure contains the width in pixels, height in pixels, bitdepth in bits, which should be 1024x768x32 as it is what you're using. The pitch means bytes per line. You need to use that as well. My GitHub repository has some graphical code in kernel/gdi.asm and kernel/vesa.asm. It's in assembly language, but shouldn't be too hard to convert to C.
EDIT: Forgot to say this, "pixelwidth" is just "bitdepth/8".

I don't know assembly memory access, so what I should do?

For a start, check out the multiboot info structure here, the one described in the multiboot specification is severely outdated. Then try to write some code which will be able to put pixels. If you don't seem to get it right, see here. But, please, try your best before asking here again, and when you get it working, please understand if it is working properly or not, and why happens that.


Regards,
glauxosdever

[abcdef4bfd]

Hi,

The VBE mode information structure contains the width in pixels, height in pixels, bitdepth in bits, which should be 1024x768x32 as it is what you're using. The pitch means bytes per line. You need to use that as well. My GitHub repository has some graphical code in kernel/gdi.asm and kernel/vesa.asm. It's in assembly language, but shouldn't be too hard to convert to C.
EDIT: Forgot to say this, "pixelwidth" is just "bitdepth/8".

I don't know assembly memory access, so what I should do?

For a start, check out the multiboot info structure here, the one described in the multiboot specification is severely outdated. Then try to write some code which will be able to put pixels. If you don't seem to get it right, see here. But, please, try your best before asking here again, and when you get it working, please understand if it is working properly or not, and why happens that.


Regards,
glauxosdever

OK.

[abcdef4bfd]

Nothing is working. Code of putpixel:

Code: Select all

   unsigned long pixindex=y*vbeMode.pitch+x*(vbeMode.bpp/8);
   framebuffer[pixindex+0]=color;
   framebuffer[pixindex+1]=color>>8;
   framebuffer[pixindex+1]=color>>16;

[glauxosdever]

Hi,

Nothing is working. Code of putpixel:

Code: Select all

   unsigned long pixindex=y*vbeMode.pitch+x*(vbeMode.bpp/8);
   framebuffer[pixindex+0]=color;
   framebuffer[pixindex+1]=color>>8;
   framebuffer[pixindex+1]=color>>16;

Well, what have you tried until now? You say it's not working, what are the exact results?


Regards,
glauxosdever

[abcdef4bfd]

Hi,

Nothing is working. Code of putpixel:

Code: Select all

   unsigned long pixindex=y*vbeMode.pitch+x*(vbeMode.bpp/8);
   framebuffer[pixindex+0]=color;
   framebuffer[pixindex+1]=color>>8;
   framebuffer[pixindex+1]=color>>16;

Well, what have you tried until now? You say it's not working, what are the exact results?


Regards,
glauxosdever

I tried only this, and my mind are not having any other solvings of this problem. Nothing is displaying, just black screen.

[abcdef4bfd]

Is anybody here? I still have this problem.

[abcdef4bfd]

Close the thread, I'll create new named "Putting pixels in VBE 1024*768*32 mode".