I'm trying to tint a texture like Photoshop (and photofiltre) does. I use shaders to do that.
I can't find anything on the net so I post here.
For the light tint, I make sure that if each rgb colors are above 0.85, then I alter them, but it varies depending on the distance.
"if( texcol.r > 0.85 ) gl_FragColor.r = texcol.r * altered_red;\n" same for .g and .b
Not sure what I need to do for the light tint.
For the mid tint, I simply use pow( texcol, ( 2-vec3( altered_red, altered_green, altered_blue ) ) ). I'm not sure if it's right
As for the dark tint, I simply multiply the texture color by the altered color value (it seems to be right).
About brightness/contrast, I found this, it works well for the brightness, but for the contrast, it's not a real contrast, instead if makes the scene much more "lighty". I'm not sure how to achieve a real contrast with this shader.
Any of you guys already achieved tinturation like photoshop does ?