add icon shader

src/shaders/icon.fs

@@ -0,0 +1,29 @@
+#version 330
+
+in vec2 fragTexCoord;
+in vec4 fragColor;
+
+uniform sampler2D texture0;
+uniform sampler2D textureNormal;
+
+uniform vec3 lightDir;
+uniform vec4 lightColor;
+uniform vec4 ambientColor;
+uniform vec3 falloff = vec3(0.01, 2.4, 20);
+
+out vec4 finalColor;
+
+void main() {
+	float d = length(lightDir);
+	vec3 n = normalize(texture(textureNormal, fragTexCoord).xyz);
+	vec3 l = normalize(lightDir);
+	
+	vec3 diffuse = lightColor.rgb * lightColor.a * max(dot(n, l), 0.0);
+	vec3 ambient = ambientColor.rgb * ambientColor.a;
+	float attenuation = 1.0 / (falloff.x + falloff.y * d + falloff.z * d * d);
+	vec3 intensity = ambient + diffuse * attenuation;
+
+	vec3 final = diffuse.rgb * intensity;
+
+	finalColor = vec4(final, texture(texture0, fragTexCoord).a * 0.93);
+}