Started a simple font text class to do font rendering.

32-text-rendering/shaders/21-screen-kernel.frag.glsl

@@ -0,0 +1,38 @@
+#version 330 core
+out vec4 FragColor;
+
+in vec2 TexCoords;
+
+uniform sampler2D screenTexture;
+
+const float offset = 1.0 / 300.0;
+
+void main()
+{
+  vec2 offsets[9] = vec2[](
+      vec2(-offset,  offset), // top-left
+      vec2( 0.0f,    offset), // top-center
+      vec2( offset,  offset), // top-right
+      vec2(-offset,  0.0f),   // center-left
+      vec2( 0.0f,    0.0f),   // center-center
+      vec2( offset,  0.0f),   // center-right
+      vec2(-offset, -offset), // bottom-left
+      vec2( 0.0f,   -offset), // bottom-center
+      vec2( offset, -offset)  // bottom-right
+      );
+
+  float kernel[9] = float[](
+      1.0 / 16, 2.0 / 16, 1.0 / 16,
+      2.0 / 16, 4.0 / 16, 2.0 / 16,
+      1.0 / 16, 2.0 / 16, 1.0 / 16
+  );
+
+  vec3 col = vec3(0.0);
+
+  for(int i = 0; i < 9; i++) {
+    vec3 sampleTex = vec3(texture(screenTexture, TexCoords.st + offsets[i]));
+    col += sampleTex * kernel[i];
+  }
+
+  FragColor = vec4(col, 1.0);
+}