1 files changed, 86 insertions, 0 deletions
diff --git a/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_colorize_frag.glsl b/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_colorize_frag.glsl
new file mode 100644
index 00000000000..33b249ac09b
--- /dev/null
+++ b/source/blender/draw/engines/gpencil/shaders/fx/gpencil_fx_colorize_frag.glsl
@@ -0,0 +1,86 @@
+uniform sampler2D strokeColor;
+uniform sampler2D strokeDepth;
+
+uniform vec4 low_color;
+uniform vec4 high_color;
+uniform int mode;
+uniform float factor;
+
+out vec4 FragColor;
+
+#define MODE_GRAYSCALE   0
+#define MODE_SEPIA       1
+#define MODE_BITONE      2
+#define MODE_CUSTOM      3
+#define MODE_TRANSPARENT 4
+
+float get_luminance(vec4 color)
+{
+	float lum = (color.r * 0.2126) + (color.g * 0.7152) + (color.b * 0.723);
+	return lum;
+}
+
+void main()
+{
+	ivec2 uv = ivec2(gl_FragCoord.xy);
+
+	float stroke_depth = texelFetch(strokeDepth, uv.xy, 0).r;
+	vec4 src_pixel= texelFetch(strokeColor, uv.xy, 0);
+	float luminance = get_luminance(src_pixel);
+	vec4 outcolor;
+
+	/* is transparent */
+	if (src_pixel.a == 0.0f) {
+		discard;
+	}
+
+	switch(mode) {
+		case MODE_GRAYSCALE:
+			{
+			outcolor = vec4(luminance, luminance, luminance, src_pixel.a);
+			break;
+			}
+		case MODE_SEPIA:
+			{
+			float Red = (src_pixel.r * 0.393) + (src_pixel.g * 0.769) + (src_pixel.b * 0.189);
+			float Green = (src_pixel.r * 0.349) + (src_pixel.g * 0.686) + (src_pixel.b * 0.168);
+			float Blue = (src_pixel.r * 0.272) + (src_pixel.g * 0.534) + (src_pixel.b * 0.131);
+			outcolor = vec4(Red, Green, Blue, src_pixel.a);
+			break;
+			}
+		case MODE_BITONE:
+			{
+			if (luminance <= factor) {
+				outcolor = low_color;
+			}
+			else {
+				outcolor = high_color;
+			}
+			break;
+			}
+		case MODE_CUSTOM:
+			{
+			/* if below umbral, force custom color */
+			if (luminance <= factor) {
+				outcolor = low_color;
+			}
+			else {
+				outcolor = vec4(luminance * low_color.r, luminance * low_color.b, luminance * low_color.b, src_pixel.a);
+			}
+			break;
+			}
+		case MODE_TRANSPARENT:
+			{
+			outcolor = vec4(src_pixel.rgb, src_pixel.a * factor);
+			break;
+			}
+		default:
+			{
+			outcolor = src_pixel;
+			}
+
+	}
+
+	gl_FragDepth = stroke_depth;
+	FragColor = outcolor;
+}