pulled emboss effect

effects/emboss.frag

@@ -0,0 +1,38 @@
+/* Original source code: https://www.youtube.com/watch?v=I23zT7iu_Y4
+Adapted */
+
+varying vec2 vTexCoord;
+uniform vec2 resolution;
+uniform sampler2D tex;
+
+uniform float contrast100;
+uniform float level;
+uniform bool invert;
+uniform bool hslmode; // luminance is 2*V
+
+void main() {
+    
+    float contrast = contrast100 / 100.0;
+    
+	vec2 onePixel = vec2(floor(level) /  resolution.x, floor(level) /  resolution.y); // calculating the size of one pixel on the screen for the current resolution
+
+	vec3 color = vec3(.5); // initialize color with half value on all channels
+    if (invert) {
+        color += texture2D(tex, vTexCoord - onePixel).rgb * contrast; 
+	    color -= texture2D(tex, vTexCoord + onePixel).rgb * contrast;
+    } else {
+	    color -= texture2D(tex, vTexCoord - onePixel).rgb * contrast; 
+	    color += texture2D(tex, vTexCoord + onePixel).rgb * contrast;
+	}
+	
+	// original color
+	vec4 color0 = texture2D(tex,vTexCoord);
+	
+	// grayscale
+    float gray = (color.r + color.g + color.b) / (hslmode ? 3.0 : 1.5);
+    
+    //self-multiply
+    color = color0.rgb * gray;
+    
+	gl_FragColor = vec4(color * color0.a, color0.a);
+}

effects/emboss.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<effect name="Emboss" category="Stylize">
+	<row name="Contrast">
+		<field type="double" min="0" default="50" max="100" id="contrast100"/>
+	</row>
+	<row name="Resolution">
+		<field type="double" min="0" default="1" max="100" id="level"/>
+	</row>
+	<row name="HSL mode">
+        <field type="bool" min="0" default="100" max="100" id="hslmode"/>
+    </row>
+	<row name="Invert">
+        <field type="bool" min="0" default="100" max="100" id="invert"/>
+    </row>
+	<shader vert="common.vert" frag="emboss.frag"/>
+</effect>