GLSL color channel offset problem

I tried to create the post-effects, use of Common/Pos.vert and my custom.frag


then add the offset of the red channel


Why, instead of the offset of the red channel there are red lines?

Which effect do you try to do ?

texCoord in range ([0.0,1.0], [0.0,1.0]) if you substract (1.0,0.0) you will have a negative texCoord params, behavior depends of clamp (see OpenGL - Textures). IMHO (hypothesis), you’re in GL_CLAMP_TO_EDGE => your red is always with a texCoord(0, [0.0,1.0]) so if the pixel at the “begin of the line” is red, you’ll see red line.

yeah, david is right. I think i understand what you try to create. If i get it correctly you would like to be able to set the offset in pixels.

vec2f blueTexCoord=inTexCoord-(blueOffset/screenResolution);
uniform vec2 g_Resolution;

uniform sampler2D m_Texture;
uniform sampler2D m_DepthTexture;

in vec2 texCoord;
out vec4 outFragColor;

void main () {
	vec2 greenTexCoord = texCoord - (vec2(1,0) / g_Resolution); 
    vec4 redValue = texture2D(m_Texture, texCoord);  
    vec4 greenValue = texture2D(m_Texture, greenTexCoord);
    vec4 blueValue = texture2D(m_Texture, texCoord);  

    outFragColor = vec4(0, greenValue.g, 0, 1.0);


Hm solid green is a strange output.

Sure the texCoord and g_Resolution is porperly passed to the shader?

texCoord would be easy to debug… not sure about g_Resolution. (as a note: you have to add Resolution to your j3md)

(as a note: you have to add Resolution to your j3md)
thanks :)

Fine, you 're creating blue red stereoscopic 3D effect ( ).

Beside that, this effect was heavily in use in battlefield 4. For cutscenes, menu changes, teasers… like everywhere.