From ca2835943ca4327ad08b54af480e0c6333df201f Mon Sep 17 00:00:00 2001
From: talha <talha@talhaamir.xyz>
Date: Mon, 22 Apr 2024 03:38:29 +0500
Subject: Completed main levels to progress to text-rendering and 2d
 development.

- Only lessons left are geometry shaders and anti-aliasing
- will get to those later on soon
- need to do text rendering now
---
 source/lessons/cubemaps/shaders/fbo.fs.glsl | 72 +++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)
 create mode 100644 source/lessons/cubemaps/shaders/fbo.fs.glsl

(limited to 'source/lessons/cubemaps/shaders/fbo.fs.glsl')

diff --git a/source/lessons/cubemaps/shaders/fbo.fs.glsl b/source/lessons/cubemaps/shaders/fbo.fs.glsl
new file mode 100644
index 0000000..e12ad33
--- /dev/null
+++ b/source/lessons/cubemaps/shaders/fbo.fs.glsl
@@ -0,0 +1,72 @@
+#version 330 core
+
+in vec2 TexCoords;
+uniform sampler2D TexId;
+out vec4 FragColor;
+
+vec4 filter_color_invert(vec4 color)
+{
+  vec4 res = vec4(vec3(1.0) - vec3(color), 1.0);
+  return res;
+}
+
+vec4 filter_color_grayscale(vec4 color)
+{
+  // we will need to average the colors
+  // float average = (color.x + color.y + color.z) / 3.0f;
+  // in reality, human our most sensitive towards green and least to blue, so will need to weight those
+  float average = 0.2126 * color.r + 0.7152 * color.g + 0.0722 * color.b;
+  vec4 res = vec4(vec3(average), 1.0);
+
+  return res;
+}
+
+// @note: different kernels for experimentation
+const float kernel_sharpen[9] = float[](
+    -1, -1, -1,
+    -1,  9, -1,
+    -1, -1, -1
+);
+
+const float kernel_blur[9] = float[](
+    1.0/16.0, 2.0/16.0, 1.0/16.0,
+    2.0/16.0, 4.0/16.0, 2.0/16.0,
+    1.0/16.0, 2.0/16.0, 1.0/16.0
+);
+
+const float kernel_edge_detection[9] = float[](
+    1,  1,  1,
+    1, -8,  1,
+    1,  1,  1
+);
+
+vec4 filter_kernal_effects() 
+{
+  const float offset = 1.0/300.0;
+  vec2 offsets[9] = vec2[](
+    vec2(-offset,  offset),    // top left
+    vec2(      0,  offset),    // top center
+    vec2( offset,  offset),    // top right
+    vec2(-offset,       0),    // center left
+    vec2(      0,       0),    // center center
+    vec2( offset,       0),    // center right
+    vec2(-offset, -offset),    // bot left
+    vec2(      0, -offset),    // bot center
+    vec2( offset, -offset)    // bot right
+  );
+
+  float kernal[9] = kernel_edge_detection;
+  vec3 kernalValue = vec3(0.0);
+  vec3 sampleTex[9];
+  for (int i=0; i<9; i++) {
+    sampleTex[i] = vec3(texture(TexId, TexCoords + offsets[i]));
+    kernalValue += (kernal[i] * sampleTex[i]);
+  }
+
+  vec4 res = vec4(kernalValue, 1.0);
+  return res;
+}
+
+void main() {
+    FragColor = texture(TexId, TexCoords);
+}
-- 
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