Messages

16

General discussions / Re: SFML with hardware accelerated graphics on the raspberry pi

« on: April 05, 2015, 05:00:40 pm »

So is that usable for a project (mainly graphics and sounds) or absolutely not because of the latency ?

17

Graphics / Re: Convert from one pixel format to another

« on: April 04, 2015, 03:08:42 pm »

It works, here is the code :

    const uint16_t* pixels = (uint16_t*) data;

    Texture::bind(&gameTexture);
    for (int i = 0; i < height; i++)
    {
        glTexSubImage2D(GL_TEXTURE_2D, 0, 0, i, width, 1, GL_RGB, GL_UNSIGNED_SHORT_5_6_5, pixels);
        pixels += pitch/2;
    }
 

I love you <3

18

Graphics / Re: Convert from one pixel format to another

« on: April 03, 2015, 11:43:53 pm »

Here is what the game looks like (the window is too big that's normal) :

19

Graphics / Re: Convert from one pixel format to another

« on: April 03, 2015, 08:55:19 pm »

I've tried this :

void videoRefreshCallback(const void *data, unsigned width, unsigned height, size_t pitch)
{
    Texture::bind(&gameTexture);
    glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, GL_RGB, GL_UNSIGNED_SHORT_5_6_5, data);
}
 

It doens't seem to work, the pixels are showing on the screen but with a messed up aspect (close to the result I have by using gameTexture.update(data); without converting anything).

The pitch is the size of one line of pixels, in bytes

20

Graphics / Re: Convert from one pixel format to another

« on: April 03, 2015, 07:17:14 pm »

You can bind the sf::Texture yourself, and then transfer data to it in your format:

sf::Texture::bind(&tex);
glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, GL_RGB, GL_UNSIGNED_SHORT_5_6_5, myarrayofunisgnedshorts);

I have no idea if this will work on raspberry.

That looks super interesting, is the array format the same as the one I'm using (arrays of pixels, one entry per pixel) or is it the one currently used by SFML (array of pixel channels, several entry per pixel) ?

21

Graphics / Re: Convert from one pixel format to another

« on: April 03, 2015, 06:13:09 pm »

You can try modifying things, but there's no real gain for SFML itself. I mean you can ask yourself why does SFML have to adapt the RGB565 format instead of liretro providing an RGBA output?

The thing is that libretro is quite a huge project, and there is more that 70 different consoles cores that can use 3 different pixel formats, RGB565 is more accurate and faster for most of the old consoles (like the SNES), but for the PSX for example it's XRGB8888, so... there isn't much I can do about it, apart from taking each one of them and creating a conversion method for SFML's format =/

22

Graphics / Convert from one pixel format to another

« on: April 03, 2015, 05:55:56 pm »

Hello,

I've been annoying you with this issue on the IRC Chat, I'll continue here instead, I find it more practical for me and more people might help.

So here is the deal : I am trying to create a tiny libretro frontend using SFML, which point is to eventually run on a Raspberry Pi. I have an emulation core which gives me every frame the image that I'm supposed to display. The thing is that the pixel format is not the same as the one SFML's using.

libretro can support several emulation consoles, which can use three different pixel formats. For now I'll just focus on one : RGB565.

The core provides me, every frame, an uint16_t * containing the pixels this way : { rrrrrggggggbbbbb, rrrrrggggggbbbbb, rrrrrggggggbbbbb, etc...}.

On the other hand, SFML requires an RGBA8888 format, plus a weird uint8_t * array disposition : {rrrrrrrr, gggggggg, bbbbbbbb, aaaaaaaa, rrrrrrrr, gggggggg, bbbbbbbb, aaaaaaaa, rrrrrrrr, gggggggg, bbbbbbbb, aaaaaaaa, etc...}.

On the IRC we eventually came to a working method to convert each pixel to three uint8_t containing the red, green and blue channels (well, I think it works).

Here is the snippet I have - pixelsBuffer is the final array containing the pixels to be displayed, and videoRefreshCallback is the function called every frame to update pixelsBuffer :

//The final pixels buffer (the size is fixed for now), which should be RGBA8888
uint8_t pixelsBuffer[229376];

void videoRefreshCallback(const void *data, unsigned width, unsigned height, size_t pitch)
{
    uint16_t * pixels = (uint16_t *) data; //the uint16_t array of RGB565 pixels

    for (int y = 0; y < height; y++)
    {
        for (int x = 0; x < width; x++)
        {
            uint16_t actualPixel = pixels[(pitch*y)/2 + x];

            uint8_t r = (actualPixel >> 8) & 0xF8;
            uint8_t g = (actualPixel >> 3) & 0xFC;
            uint8_t b = (actualPixel) << 3;

            pixelsBuffer[?] = r;
            pixelsBuffer[? * 4 + 1] = g;
            pixelsBuffer[? * 4 + 2] = b;
            pixelsBuffer[? * 4 + 3] = 0xFF;
        }
    }

    gameTexture.update(pixelsBuffer, width, height, 0, 0); //we update the texture drawn in the main loop
}
 

Okay, so the pixel conversion works here (I guess), but I don't really know how to put them in pixelsBuffer (where the ? are).

Could you help me ? I also have few other questions :

• isn't there a more optimized solution to do this ? i think the double-loop solution is heavy, it's supposed to run on a Raspberry and I might need to implement some more high-qualities consoles (with more pixels to process each frame)
• wouldn't be more easy to extend SFML to support more pixels formats ? I looked at the Texture::update() code, and I think we can change GL_ARGB to pretty much every format supported by GL (RGB565 included), but this doesn't solve the array format problem, switching from one array of pixels (one entry per pixel) to one array of pixel colors (3 or 4 entry per pixel, depending on the alpha channel)

Thanks a lot !

23

General / Re: Using SFML with a Raspberry Pi 2 B ?

« on: April 01, 2015, 07:10:16 pm »

I'll try to make a little program on Linux and then try to compile it on the Rasp. (using Qt).

24

General / Re: Using SFML with a Raspberry Pi 2 B ?

« on: April 01, 2015, 06:21:41 pm »

That looks super interesting, sorry I didn't find it before ^^ You can close this topic, I'll move to the already existing one.

25

General / Using SFML with a Raspberry Pi 2 B ?

« on: April 01, 2015, 05:36:03 pm »

Hello,

I am actually testing some librairies for a small project, its point is to be running on a Raspberry Pi (Model 2B). I am actually testing SDL2, and I'm not very found of it (I think it's too scattered, it goes in all directions I hate it). I heard of SFML, and I think I might really like it, but before actually testing it I must be sure it'll work properly on the Raspberry.

I don't own the beast yet, it will be shipped within 1/2 weeks. Do you think SFML will work properly on it, with graphics working and fast enough to run a fluent 2D game on a HD TV ?

Thanks !