Topics

1

Graphics / Inverting a sprite

« on: July 13, 2011, 03:03:42 am »

Hello, I'm trying to invert the colors for a single sprite and I can't seem to get it right. How do I receive the current pixel's color (from the sprite) in the shader? At first I tried gl_Color to no avail:

Code: [Select]


uniform bool invert;

void main()
{
    if(invert)
        gl_FragColor = vec4(255.0 - gl_Color.r, 255.0 - gl_Color.g, 255.0 - gl_Color.b, 1.0);
    else
        gl_FragColor = gl_Color;
}


I also tried another google-inspired solution:

Code: [Select]


uniform bool invert;
uniform sampler2D screenColorBuffer;

void main()
{
    vec4 color =  gl_TexCoord[0];
    if(invert)
    {
        gl_FragColor = 1.0-texture2D(screenColorBuffer,gl_TexCoord[0].st);
        gl_FragColor.a = 1.0;
    }
    else
        gl_FragColor = color;
}


Maybe I'm just not sure what to search for... this GLSL stuff is impossible to sort out for some reason. Is there a certain variable I should use in this scenario?

Thanks

2

Graphics / Shaders don't work when running as a screensaver

« on: May 12, 2011, 03:42:03 pm »

I'm writing a screensaver using SFML 2.0, however I am running into some problems with shaders.

I should state that I haven't written a "formal" windows api screensaver, I am using the normal main and only renaming the screensaver from .exe to .scr while I am testing. This is legal and in fact works in setting up the display/drawing, but for some reason shaders fail to work.

At first I thought there might have been a problem with the execution directory but even when hard-coding the shader location it was failing. After some debugging I discovered SFML was simply unable to use shaders when the extension was changed to .scr.

Also, slightly off-topic, but has anyone had any success with screensavers in SFML in the past? Did you use <screensaver.h> and go through the "proper" windows protocol? I'm trying to decide if I should even bother with the winapi or just stick with main and command line switches. I also can't decide if I really need SFML or not... I'm really only using it to get an opengl context and load the fragment shaders which could easily be done the old-fashioned way.

3

General discussions / Problem compiling SFML 2.0 program

« on: February 03, 2011, 11:28:24 pm »

I followed the instructions to build SFML 2.0 with CMake and it seemed to work without a problem. So now I try to compile against the library but I keep getting errors:

Code: [Select]

obj\Debug\Game.o: In function `Game':
C:/Users/Mitchell/Programming/Projects/Demise/Game.cpp:13: undefined reference to `_imp___ZN2sf9VideoModeC1Ejjj'
C:/Users/Mitchell/Programming/Projects/Demise/Game.cpp:13: undefined reference to `_imp___ZN2sf12RenderWindowC1ENS_9VideoModeERKSsmRKNS_15ContextSettingsE'
C:/Users/Mitchell/Programming/Projects/Demise/Game.cpp:14: undefined reference to `_imp___ZN2sf6Window17SetFramerateLimitEj'
C:/Users/Mitchell/Programming/Projects/Demise/Game.cpp:27: undefined reference to `_imp___ZN2sf5ImageC1Ev'
C:/Users/Mitchell/Programming/Projects/Demise/Game.cpp:28: undefined reference to `_imp___ZN2sf5Image12LoadFromFileERKSs'
C:/Users/Mitchell/Programming/Projects/Demise/Game.cpp:30: undefined reference to `_imp___ZN2sf5Image9SetSmoothEb'
C:/Users/Mitchell/Programming/Projects/Demise/Game.cpp:13: undefined reference to `_imp___ZN2sf9VideoModeC1Ejjj'
C:/Users/Mitchell/Programming/Projects/Demise/Game.cpp:13: undefined reference to `_imp___ZN2sf12RenderWindowC1ENS_9VideoModeERKSsmRKNS_15ContextSettingsE'
C:/Users/Mitchell/Programming/Projects/Demise/Game.cpp:14: undefined reference to `_imp___ZN2sf6Window17SetFramerateLimitEj'
C:/Users/Mitchell/Programming/Projects/Demise/Game.cpp:27: undefined reference to `_imp___ZN2sf5ImageC1Ev'
C:/Users/Mitchell/Programming/Projects/Demise/Game.cpp:28: undefined reference to `_imp___ZN2sf5Image12LoadFromFileERKSs'
C:/Users/Mitchell/Programming/Projects/Demise/Game.cpp:30: undefined reference to `_imp___ZN2sf5Image9SetSmoothEb'
obj\Debug\Game.o:C:/Users/Mitchell/Programming/Projects/Demise/Game.cpp:58: undefined reference to `_imp___ZN2sf6Window5CloseEv'
obj\Debug\Game.o:C:/Users/Mitchell/Programming/Projects/Demise/Game.cpp:55: undefined reference to `_imp___ZN2sf6Window8GetEventERNS_5EventE'
obj\Debug\Game.o:C:/Users/Mitchell/Programming/Projects/Demise/Game.cpp:60: undefined reference to `_imp___ZNK2sf6Window8GetInputEv'
obj\Debug\Game.o:C:/Users/Mitchell/Programming/Projects/Demise/Game.cpp:63: undefined reference to `_imp___ZN2sf5Color5BlackE'
obj\Debug\Game.o:C:/Users/Mitchell/Programming/Projects/Demise/Game.cpp:63: undefined reference to `_imp___ZN2sf12RenderTarget5ClearERKNS_5ColorE'
obj\Debug\Game.o:C:/Users/Mitchell/Programming/Projects/Demise/Game.cpp:65: undefined reference to `_imp___ZN2sf6Window7DisplayEv'
obj\Debug\Game.o:C:/Users/Mitchell/Programming/Projects/Demise/Game.cpp:52: undefined reference to `_imp___ZNK2sf6Window8IsOpenedEv'
collect2: ld returned 1 exit status


So yeah, what might cause this? The program is trivially simple, it's just a basic game loop at the moment. I have the compiler/linker search directories set correctly and everything, and I'm using the exact same compiler I used to compile SFML (TDM-GCC). Using SVN revision 1786