need a simple shader

[Acki]

hi,
I need a simple shader, but I have no experiences with shaders... :'(
I found many tutorials on the web, but I have no time (and pacience) to dig through tons od tutorial just for a single shader...

what I need is a shader that darkens/lightens the scene depending on a value...
maybe a value from 0 to 100 (0 = dark and 100 = bright)...
I want to create a day/night/dusk/dawn effect...

I guess this would be a post process shader, right ???
mainly I need it for dx, but one for ogl in addition would be great, too !!!

also I'm not sure how to use post process shaders with Irrlicht, the shader tutorial only shows the use with scene nodes...
or do I simply have to set the shader to the camera node for this ???

I hope someone is so kind...

thx, Acki

[Lonesome Ducky]

With post processing, you would usually render the scene to a texture, then render to a screen aligned quad. This would allows the shader to change colors of the screen and so on.

[Bate]

That's how you could brighten a texture in GLSL. uniform float adjust is your callback var 1.0 means no change, a higher value brightens the texture up. Not exactly what you want, but maybe it helps. I'm still learning myself

// Vertex Shader

Code: Select all

varying vec2 tex_coord;

void main()
{
  gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;
  tex_coord = vec2(gl_MultiTexCoord0);
}

// Frag Shader

Code: Select all

varying vec2 tex_coord;
uniform sampler2D tex_color;
uniform float adjust;

void main()
{
  gl_FragColor = texture2D(tex_color, tex_coord) * adjust;
}

[Acki]

With post processing, you would usually render the scene to a texture, then render to a screen aligned quad. This would allows the shader to change colors of the screen and so on.

ahh, I saw a tutorial of game studio shaders and they used the camera for the post processing directly...
well, in this case I'll have to overthink my strategy though...

1.0 means no change, a higher value brightens the texture up. Not exactly what you want, but maybe it helps.

that look pretty promissing !!!

now I have basics I can work/test with !!!
I guess I'll get the implementation to work now, at least for ogl (maybe I get it converted to dx on myself)...

thank you both, very much !!!