Simple static 2d shadows

[general sirhc]

Okay so I got everything working with the views, I was doing some bad maths that was screwing it up. However I finally managed to find something that isn't my fault (at least I don't think it is)

In the documentation you say

Clear (const Color &color=Color(0, 0, 0))
Clear the entire target with a single color.

However I made a RenderImage and just because I am a persistant bastard I decided I would put

image.Clear(sf::Color(0,0,0,0));

And to my surprise it worked... The RenderImage was invisible and the stuff I drew on it wasn't! I tried different background colors just in case I had white on white but I am pretty confident its not me. If I am right about this we will both be very happy =)

(Sorry if I didn't make sense, im excited about RenderImage's having alpha support!)

[Laurent]

Of course RenderImage supports alpha

I don't understand what's "wrong" with what you showed, it behaves as expected.

[general sirhc]

Well the documentation says that clear only supports R G B and not A

[OniLinkPlus]

Well the documentation says that clear only supports R G B and not A

No it doesn't.

[general sirhc]

Well the documentation says that clear only supports R G B and not A

No it doesn't.

Public Member Functions
    RenderImage ()
    Default constructor.
virtual    ~RenderImage ()
    Destructor.
...
...
...
void    Clear (const Color &color=Color(0, 0, 0))
    Clear the entire target with a single color.

Yes it does

[OniLinkPlus]

Well the documentation says that clear only supports R G B and not A

No it doesn't.

Public Member Functions
    RenderImage ()
    Default constructor.
virtual    ~RenderImage ()
    Destructor.
...
...
...
void    Clear (const Color &color=Color(0, 0, 0))
    Clear the entire target with a single color.

Yes it does

No, that's a default value. When you make an sf::Color, a defaults to 255, so you don't have to specify it. That const Color &color=Color(0, 0, 0) just means if you don't give it a parameter, it defaults to black.

[general sirhc]

Oh I getcha, well it would be nice if it was

clear(0,0,0,255) for the default in the documentation, I was confused for a while about it

[Laurent]

Oh I getcha, well it would be nice if it was

clear(0,0,0,255) for the default in the documentation, I was confused for a while about it

I think that reading the sf::Color documentation would help you more than me always using the 4-components color constructor

[general sirhc]

Laurent I can't help it if you have a tendency of being right all the time.

Although I still think it would be nice if it had the 4 arguments in the documentation just so it was nice and clear for dumb dumbs =)

Btw do you plan on adding more blend modes or custom blend modes? Either would be very nice =)

[Laurent]

Although I still think it would be nice if it had the 4 arguments in the documentation just so it was nice and clear for dumb dumbs =)

Ok, you win

Btw do you plan on adding more blend modes or custom blend modes? Either would be very nice =)

No, but we can talk about it. Which blending modes would you like to have?

[general sirhc]

subtract: Because its an important on for doing shadows

There is also
add
max
one
zero

But I personally have no use for them at the moment

Why can't you add custom blend modes?

[Laurent]

subtract: Because its an important on for doing shadows

Can you explain this? Usually, shadows are achieved using add + multiply (which are both available in SFML).

Why can't you add custom blend modes?

I can
I just want to keep it simple, I don't want people to have to deal with source/destination and all OpenGL modes.

[general sirhc]

Blendmodes are not my strong point so I hope you don't mind me quoting the GM manual here.

Besides the normal mode it is possible to indicate that the new color must be added to the existing color or subtracted from the existing color. This can be used to create e.g. spot lights or shadows.

Basically with subtract black takes nothing off the color already drawn and white would take all the color. So if you draw 128,128,128 color with subtract blend mode what ever it was drawn over would be darkened by half.

Also again from the book of GM it would be much better to simply have a second command which is for advanced users.

SetBlendMode(blend mode)
SetBlendModeAdv(source blend,destination blend)
Or a different naming scheme
SetBlendModeExt(source blend,destination blend)

Either way it allows basic users to keep using the simply blend modes and advanced users to use the more advanced version... Although I think it would be for intermediate users not advanced since I probably can do this through openGL how things are now instead, couldn't I?

[Laurent]

Basically with subtract black takes nothing off the color already drawn and white would take all the color. So if you draw 128,128,128 color with subtract blend mode what ever it was drawn over would be darkened by half.

Multiply is usually better to darken things, I don't think that Subtract is necessary for shadows.

Also again from the book of GM it would be much better to simply have a second command which is for advanced users.

SetBlendMode(blend mode)
SetBlendModeAdv(source blend,destination blend)
Or a different naming scheme
SetBlendModeExt(source blend,destination blend)

I know that I can provide such an API, it's just that I don't want to
I never add features jst because "I can", I add them when they are really necessary.

[general sirhc]

Personally I think its necessary, maybe you should do a poll of what the users think, blend modes are an important part of graphics rendering