Messages

1

General discussions / Re: Comparisons with SDL2

« on: July 28, 2021, 06:01:10 am »

Well my final observations after testing... To me sf::VertexBuffer was slower than sf::VertexArray when storing 50,000 objects with sf::TriangleFan using 8 points (octagon).  The difference was roughly 580ms to 110ms .

And within the sf::VertexBuffer options, The speed was fastest with sf::VertexBuffer::Static then Dynamic then Stream respectively.

Comparing sf::Texture to a regular colour fill at around 50,000 objects regular colour fill was slightly faster at about 10% (110ms to 100ms) But anything below 5000 objects the difference is negligible. (11ms to 12ms) And sf::Vertex was faster than sf::VertexArray.

With 50000 objects using sf::Vertex in loop, using textures was 23ms as opposed to around 17ms with color fill. With 5000 objects both resulted about 1 or 2ms each.

Lastly, avoiding divisions and optimizing algorithms did speed up the rendering by another 1-4%. And less points (for instance using an octagon instead of circle) sped things up even more.

Of course, on stackoverflow there was one QuadTree expert who claimed to hit a million particles at 60fps! But I'm happy with 50,000 objects for now, maybe one day I'll tackle dynamic QuadTrees, and re-examine SDL2 as well.

Edit: Running i9-9900k + Nvidia RTX 3090 FE windows 10 x64

2

General discussions / Re: Comparisons with SDL2

« on: July 27, 2021, 05:34:38 pm »

As I lay down each night and think of nothing but code, I've decided to re-visiting this comparison once again as I may have been biased in 1 important aspect.

On the SDL2 side I should try to point less vertices to see if that will speed up the process even more. And on SFML side I should try sf::VertexArray to see if there's any noticeable difference with sf::Vertex. And then while on that subject check performance with sf::VertexBuffer.

Not sure why I'm so ocd on this but I've gone so far tangent from my original project I might as well examine this before I make my final decision. =)

3

General discussions / Comparisons with SDL2

« on: July 27, 2021, 01:53:12 am »

If this has been discussed and already beaten to death well I apologize in advance.

But I was working on collision detection & resolution example through SFML with many objects around 900 circle objects in debug mode when things started to bog down. I know in release mode it's perfectly fine at 60 fps but out of curiosity I wanted to try SDL2 to see if it's anymore efficient.

Unfortunately SDL2 doesn't have circle primitive shapes so I had to go through a bunch of tutorials to get that up and running. There were 2 methods in SDL2 to create a circle shape one was less efficient than the other, while the other one was extremely efficient as it used 1/4 of the circle drawing then used symmetry to mirror the rest and blit textures.

While this managed to cut down the rendering by at least 10-20% in SDL2 alone, SFML was still about 3x faster with sf::CircleShape and that's not even resizing the circle points down to a lesser value!

Needless to say, it most likely means my slowing down issue lies with my collision algorithm and I'm well aware of that. I probably need to use other 'fast square root' alternatives, avoid divisions as much as possible and possibly implement dynamic quadtrees (ohhh boy).

This was quite an adventure for me and I have to say I really enjoy SFML. And after avoiding SDL2 for a very long time I also like SDL2 too but SFML to me feels natural! I'm always wondering why SFML isn't as popular as it should be. It's a terrific tool for learning everything C++ and under the hood game development!

4

Graphics / Re: Possible shearing ?

« on: April 06, 2021, 07:05:42 pm »

That's a good start. I'll check that out thx Laurent!

5

Graphics / Possible shearing ?

« on: April 04, 2021, 07:50:17 pm »

Hello, if this question has been asked to death in the past then I apologize in advance but in the SFML documentation listed here:
https://www.sfml-dev.org/documentation/2.5.1/classsf_1_1Transform.php

In the detailed Description it says:

A sf::Transform specifies how to translate, rotate, scale, shear, project, whatever things.

I understand it has examples of translate, rotate, scale, and project but I haven't found any examples on shear?
I've even tried to check forums but I read somewhere that it wouldn't work since textures wouldn't be applied right and/or I would need to use in addition GLSL to do the shearing transformation is this true?

6

Graphics / Re: sfml gradient shaders question

« on: May 30, 2020, 03:01:25 am »

Oh I see what you mean. You're saying I would use sf::RenderStates state and then use state.transform = transform and also use &shader in state.shader then pass state like window.draw(circle, state);? I think I understand now, thanks.

7

Graphics / Re: sfml gradient shaders question

« on: May 30, 2020, 02:22:46 am »

So I cant use sf::Transform?

8

Graphics / sfml gradient shaders question

« on: May 29, 2020, 08:10:31 pm »

Hello, I posted a question in github SFML Gradient shaders but was told to post here instead. I was wondering if it's possible to pass an sf::Transform into the draw function along with the shader?

For example normal draw I would pass a transform like:

Code: [Select]

window.draw(circle, transform);

but with shaders that 2nd parameter is already taken up like

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window.draw(circle, &shader);

 and I cant add a third parameter. I read somewhere that I could use

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shader.setUniform("matrix", sf::Glsl::Mat4(transform));

but I added

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"uniform mat4 matrix;"

in const char RadialGradient[] but I'm getting Uniform "matrix" not found in shader. Am I doing it wrong, or overdoing it or missing something?

9

Graphics / different mouse cursors

« on: April 18, 2020, 07:48:36 am »

If this has been asked before then I apologize but I was wondering if there's more cursors besides the following:

// available types
enum     Type {
  Arrow, ArrowWait, Wait, Text,
  Hand, SizeHorizontal, SizeVertical, SizeTopLeftBottomRight,
  SizeBottomLeftTopRight, SizeAll, Cross, Help,
  NotAllowed
}

More specifically I was looking for drag and isDrag (open hand) (close hand) kind of a cursor for when mouse button is pressed and then released. I suppose I can get a png image to appear on my mouse cursor and do the handling but I was wondering if there's been more additions to the available types,  thx in advance!

10

Graphics / Re: getPixel with sf::RectangleShape

« on: April 05, 2020, 10:07:12 pm »

Sounds like you're trying to see if a point is inside a rotated rectangle. That's simpler:

if (rectangle.getLocalBounds().contains(rectangle.getInverseTransform().transformPoint(point)))
    pointIsInsideRectangle = true;

@Hapax, Dude thanks so much. This did it exactly. I was looking for something similar to JavaScript's ctx.isPointInPath() and this did it perfectly. My other method was image getPixel() but I had to rotate the png rectangle image ahead of time which was very cumbersome. Thanks again!

11

Graphics / Re: getPixel with sf::RectangleShape

« on: April 05, 2020, 07:59:15 pm »

Oooo, I'm going to have to test that out!! That looks real promising.

12

Graphics / Re: getPixel with sf::RectangleShape

« on: April 04, 2020, 08:57:11 pm »

That's what I figured. My other 'hacky' solution was to create a png file with a red rectangle already rotated. And from that I load the texture into the image and then check getPixel() for red. When I have more time I need to redo this and use your method.

13

Graphics / Re: getPixel with sf::RectangleShape

« on: April 04, 2020, 01:44:10 am »

Is there a difference from using

Code: [Select]

sf::Transform transform;
transform.rotate(angle);
window.draw(rect, transform);
as opposed to just

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rect.setPosition(pos);
rect.setOrigin(rect.getSize().x/2, rect.getSize().y/2);
rect.setFillColor(sf::Color::Red);
rect.rotate(angle);
window.draw(rect);

 Also when I use getGlobalBounds() after the rotation it seems to ignore the rotation, it still checks it's normal non rotated bounds.

14

Graphics / getPixel with sf::RectangleShape

« on: April 03, 2020, 11:16:57 pm »

Hi , this may sound like a noobish question but is there a way to get a pixel color information from a rotated rectangle?

I'm asking this because so far I've been using texture images to getPixel just fine, but what if I want to rotate a simple rectangle and then check to see it's color?

My current workaround was to simply create a png file with an image of a rectangle already rotated and then checking getPixel() from there, but I thought maybe there's a better method to this? Thank you!

15

Graphics / Re: is it possible to rotate a line?

« on: January 17, 2020, 08:55:04 pm »

How to use sf::Transform to draw an entity:
https://www.sfml-dev.org/tutorials/2.5/graphics-transform.php#custom-transforms

How to build the right transform for what you want:
https://www.sfml-dev.org/documentation/2.5.1/classsf_1_1Transform.php#af0b7cc3fed36d0fa22d5d331a779eee2

That did it. Thanks man. I couldn't figure out how to add another parameter for window.draw when I already had

Code: [Select]

w.draw(lines, 2, sf::Lines);
Passing transform to the draw function had only 2 arguments stated here
https://www.sfml-dev.org/tutorials/2.5/graphics-transform.php#custom-transforms

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window.draw(entity, transform);
on a whim I just added transform at the end of

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w.draw(lines, 2, sf::Lines, transform);
And then the .rotate() function had the center argument for rotation and that did the trick. Thx again Laurent!!