Add false color rendering

shaders/image.frag

@@ -5,6 +5,7 @@ uniform vec3 mtf_param;
 uniform bool bw;
 uniform bool invert;
 uniform bool srgb;
+uniform bool false_color;
 uniform vec3 whiteBalance;
 in vec2 qt_TexCoord0;
 layout(location = 0) out vec4 color;
@@ -23,6 +24,20 @@ vec4 MTF(vec4 x, vec3 m)
     return ((m.y - 1) * x) / ((2 * m.y - 1) * x - m.y);
 }
 
+vec3 falsecolor(float color)
+{
+    const vec3 pallete[] = vec3[](
+            vec3(1.0, 0.0, 1.0), //magneta
+            vec3(0.0, 0.0, 1.0), //blue
+            vec3(0.0, 1.0, 1.0), //cyan
+            vec3(0.0, 1.0, 0.0), //green
+            vec3(1.0, 1.0, 0.0), //yellow
+            vec3(1.0, 0.0, 0.0), vec3(1.0, 0.0, 0.0));//red
+    color *= 5.0;
+    int i = int(color);
+    return mix(pallete[i], pallete[i+1], fract(color));
+}
+
 vec3 checker()
 {
     vec2 pattern = fract(gl_FragCoord.xy * 0.0625) - 0.5;
@@ -34,6 +49,7 @@ void main(void)
     color = texture(qt_Texture0, qt_TexCoord0);
     if(bw)color = color.rrra;
     color = MTF(color, mtf_param);
+    if(false_color)color.rgb = falsecolor(color.r);
 
     if(invert)color.rgb = vec3(1.0) - color.rgb;