Add (updated) source code for Text Rendering chapter.

src/7.in_practice/2.text_rendering/text.fs

@@ -0,0 +1,12 @@
+#version 330 core
+in vec2 TexCoords;
+out vec4 color;
+
+uniform sampler2D text;
+uniform vec3 textColor;
+
+void main()
+{    
+    vec4 sampled = vec4(1.0, 1.0, 1.0, texture(text, TexCoords).r);
+    color = vec4(textColor, 1.0) * sampled;
+}