pseudocode.txt

Pseudocode for Sobel Operator (GLSL FragShader)

BEGIN
    uniform -> uTexture    // Main texture
    uniform -> uResolution // Renderbuffer size
    uniform -> uThreshold  // Black/white threshold value

    kernalY -> matrix(3x3) {
        -1, 0, 1,
        -2, 0, 2,
        -1, 0, 1
    }

    kernalX -> matrix(3x3) {
        -1, -2, -1,
         0,  0,  0,
         1,  2,  1
    }

    # Main function (per fragment)
    MAIN
        
        # Gradient intensity on the x,y direction
        gX -> 0.0
        gY -> 0.0

        # x,y axis kernal pass
        FOR each value between -1 to 1 as i THEN
            FOR each value between -1 to 1 as j THEN

                # Calculate uvs of surrounding fragments
                x -> (get_uvs().x / uResolution.x) + float(i) / uResolution.x
                y -> (get_uvs().y / uResolution.y) + float(j) / uResolution.y

                # Add intensity of the gradient on the x,y axies
                gX += texture(uTexture, vec2(x,y)).r * float(kernalX[i+1][j+1])
                gY += texture(uTexture, vec2(x,y)).r * float(kernalY[i+1][j+1])
            
            ENDFOR
        ENDFOR

        # Euclidean Distance
        mag = sqrt(pow(gX, 2) + pow(gY, 2))

        if (g > uThreshold){
            finalColour = vec4(g, g, g, 1.0);
        } else {
            finalColour = vec4(0.0, 0.0, 0.0, 1.0);
        }

    ENDMAIN
END