1 files changed, 44 insertions, 0 deletions
diff --git a/matchblox/shaders/grayscale.frag b/matchblox/shaders/grayscale.frag
new file mode 100644
index 0000000..0f4ddaf
--- /dev/null
+++ b/matchblox/shaders/grayscale.frag
@@ -0,0 +1,44 @@
+uniform vec3 g_ConversionWeights;
+uniform sampler2D g_TexSampler;
+
+
+varying vec4 ambient, diffuse;
+varying vec3 normal, lightdir, halfvector;
+
+void main()
+{
+	float NdotL, NdotHV, gray;
+	vec3  n     = normalize(normal);
+	vec4  texcolor = texture2D(g_TexSampler, gl_TexCoord[0].st),
+	      fragcolor = ambient,
+	      color;
+	
+	//compute the dot pruduct of the normalized normal and light direction
+	NdotL = max(dot(n, lightdir), 0.0);
+	
+	if (NdotL > 0.0)
+	{
+		//add diffuse light component
+		fragcolor += diffuse * NdotL;
+		
+		//compute the dot product of the normal and half vector (of the lightdir and eye position)
+		NdotHV = max(dot(n, halfvector), 0.0);
+		
+		fragcolor += gl_FrontMaterial.specular * gl_LightSource[0].specular * 
+					 pow(NdotHV, gl_FrontMaterial.shininess);
+	}
+	
+	//modulate the fragment color with the texel color for the final color
+ 	color =  texcolor * fragcolor;
+	
+	//convert to grayscale using NTSC conversion weights 
+	//gray = dot(color.rgb, vec3(0.299, 0.587, 0.114));
+	gray = dot(color.rgb, g_ConversionWeights);
+	//gray = color.r * 0.299 + color.g * 0.587 + color.b * 0.114;
+
+	//copy grayscale to rgb components and use the alpha from the final color
+	gl_FragColor = vec4(gray, gray, gray, color.a);
+	
+	// convert grayscale to sepia
+    //gl_FragColor = vec4(gray * vec3(1.2, 1.0, 0.8), color.a);
+}
+\ No newline at end of file