Messages

1

Graphics / Image::CopyScreen

« on: November 23, 2008, 10:57:22 pm »

It wouldn't make sense, as RenderImage is already an image.

Yes you are right, thanks. I'll wait the update to PostFX  

2

Graphics / Strange Collision

« on: November 23, 2008, 10:45:18 pm »

Are you checking both X and Y values?

Try something like this:

Code: [Select]

// Object-to-object bounding-box collision detector:
short int Sprite_Collide(sprite_ptr object1, sprite_ptr object2) {
 
    int left1, left2;
    int right1, right2;
    int top1, top2;
    int bottom1, bottom2;

    left1 = object1->x;
    left2 = object2->x;
    right1 = object1->x + object1->width;
    right2 = object2->x + object2->width;
    top1 = object1->y;
    top2 = object2->y;
    bottom1 = object1->y + object1->height;
    bottom2 = object2->y + object2->height;

    if (bottom1 < top2) return(0);
    if (top1 > bottom2) return(0);

    if (right1 < left2) return(0);
    if (left1 > right2) return(0);

    return(1);

};


(Pasted from GameDev.net)

Or read the full article: http://www.gamedev.net/reference/articles/article735.asp

3

Graphics / Strange Collision

« on: November 23, 2008, 06:33:59 pm »

Code: [Select]

if(Player.GetPosition().x + Player.GetSize().x <= Wall.GetPosition().x)
      {
//not the important part...
         if(Player.GetPosition().x <= 1024-Player.GetSize().x)   Player.Move( 400*Window.GetFrameTime(), 0);
      }


Here you are checking X position for a possible collision...and the Y ?

4

Graphics / Image::CopyScreen

« on: November 22, 2008, 03:57:21 pm »

Hi all, I would like to know if there is some particular reason for the function Image::CopyScreen to use a RenderWindow pointer instead of a more generic RenderTarget.

I'm asking that because PostFX uses CopyScreen and this limits the use of PostFX to RenderWindow (I cannot use PostFX with my RenderImage class  :wink: ).

5

Graphics / just draw a image, not a sprite

« on: November 21, 2008, 09:25:42 pm »

According to the NVIDIA article:

Methods of data movement:

....
- glBegin() / glEnd(): easy to use but bad performance, spoon feeding, multiple layers per call, only a few words of data per API call, function calls are expensive.
....

My personal thought is that glBegin / glEnd is more than good for general purposes and it is easy to use. I think that only with a big amount of vertexes to render each frame these API calls could slow down the rendering time and it also depends on the hardware.

One thing that I learned that can improve the performance is to group your primitive rendering calls first by primitive type, then by texture, then by blending mode.

If we talk about SFML I think there is already in the roadmap a way to " Optimize rendering of huge amounts of drawables".

6

Graphics / svn: Image.LoadFromFile and Image.Create crashes

« on: November 21, 2008, 09:31:18 am »

Very happy to have been helpful

7

Graphics / just draw a image, not a sprite

« on: November 21, 2008, 09:27:24 am »

It isn't the drawing that is the bottleneck, it's the lines that are being generated each frame. You're computing a normal 12 times per asteroid every frame.

True, but Draw() function calls glBegin/glEnd each time and this could have an impact on the performance in some situations.

If we talk about performance when whe have a huge amount of vertexes:

1) Worse: glBegin/glEnd
2) Better: Vertex arrays
3) Best: VBOs / Display List

This is an interesting article by NVIDIA about performance:
http://www.nvidia.com/content/nvision2008/tech_presentations/Professional_Visualization/NVISION08-Double_Your_Graphics_Performance.pdf

8

Graphics / svn: Image.LoadFromFile and Image.Create crashes

« on: November 18, 2008, 10:47:58 am »

I'm very happy if I could help you  

9

Graphics / svn: Image.LoadFromFile and Image.Create crashes

« on: November 18, 2008, 10:10:21 am »

Last news:

I tried to update the image buffer with the new power of 2 sizes before calling glTexImage2D and the code now runs ON ALL PCs without problems .

So this sort of bug can crash your program with non-power-of-2 images and even with fonts (because they are loaded into textures).

10

Graphics / svn: Image.LoadFromFile and Image.Create crashes

« on: November 18, 2008, 09:50:11 am »

Surely I'm wrong but after some investigations I've discovered a similiar thing.
I tested normal SFML code in differents PC with NVIDIA and ATI cards with the last drivers installed:

On some PC SFML code doesn't work and crashes.

I built a simple logging system for every line of code and I discovered that the problem was in the loading of images that haven't power-of-2 dimensions.

I examined the source code of CreateTexture() function, I'm far from an expert but:


If non-power-of-2-dimensions aren't supported SFML calculates new power-of-2 bigger image sizes with the function GetValidTextureSize(unsigned int Size)
but the buffer of the image just loaded is not updated with the new size.
So when we call:...

Code: [Select]

GLCheck(glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, myTextureWidth, myTextureHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, GetPixelsPtr()));


myTextureWidth and myTextureHeight are bigger than the real buffer dimension retrieved with GetPixelPtr().

Could be this the reasons of these crashes? If not I'm sorry...

11

Graphics / FlipX and FlipY for sfml strings

« on: November 17, 2008, 03:06:02 pm »

Would you be so kind as to post your code. Thanx.

The image I have posted refers to a my add-on code that is not part of the official SFML library.
Please refer to http://www.sfml-dev.org/forum/viewtopic.php?t=740 post for more informations.

12

Feature requests / Render to texture implementation question

« on: November 17, 2008, 02:59:26 pm »

I guess you're passing a local variable

Sure! Thanks, yesterday I was tired.. I solved with this two lines:

Code: [Select]


// Inverts Y-Axis
GetDefaultView().SetFromRect(FloatRect(0,static_cast<float>(myBufferWidth),static_cast<float>(myBufferHeight),0));
SetView(GetDefaultView());

I'd be glad to see your code. I'm especially interested because you're using PBuffers and not FBOs, so you need a high amount of non-portable code.

We focus only on Win32 platforms and I'm not a professional programmer so my RenderImage class has been tested only on Windows XP and Windows Vista.

I made some changes to my RenderImage class today so it should work without any SFML code modification, simply by adding RenderImage.hpp and RenderImage.cpp to the Graphics Project of SFML Solution.

-----------------------------

Here is my code, please feel free to throw it away, modify or use it. I hope it could be of little help.

I'm especially interested because you're using PBuffers and not FBOs

Have PBuffers a better compatibility than FBO?
 ( http://lwjgl.org/wiki/doku.php/lwjgl/tutorials/opengl/pbuffervsfbo )

My RenderImage references: http://ati.amd.com/developer/ATIpbuffer.pdf

-----------------------------

I also made an example to show RenderImage use, it's included in the rar file.



RenderImage and Example sources here:
http://www.megaupload.com/?d=9C19OO5R

-----------------------------

TODO:

Add checking to control that we haven't lost our pbuffer due to a display mode change with:

Code: [Select]

wglQueryPbufferARB(hPBuffer, WGL_PBUFFER_LOST_ARB, &flag);


13

Graphics / FlipX and FlipY for sfml strings

« on: November 16, 2008, 03:03:37 pm »

14

Feature requests / Render to texture implementation question

« on: November 16, 2008, 10:37:24 am »

I "potentially" solved the problem:

SetView(View(FloatRect(0,myBufferWidth,myBufferHeight,0)));

This simple line inverts y-axis and all works but...

But in the original code this line breaks the program because myCurrentView is a constant:
const View* myCurrentView;

So if I use SetView(), this function generates weirds values and corrupts the program.

I had to modify:
const View * myCurrentView;
to
View myCurrentView;

and so SetView() works without any problem.

I was happy because I succeded to implement RenderImage without changing any single line of the original SFML code (except for CreateTexture() that I had to make it virtual).

Now I had to change a core part of SFML that is myCurrentView member of RenderTarget class so I don't think my RenderImage class could be useful for you..

But if you find a solution I will post my RenderImage class if it can be of any help..

Best regards.

15

Graphics / FlipX and FlipY for sfml strings

« on: November 16, 2008, 09:39:10 am »

When render to texture will be avaiable you could render text to a texture and display it flipped or rotated.