1 files changed, 110 insertions, 0 deletions
diff --git a/advanced_opengl/10.antialiasing/shaders/screen.frag b/advanced_opengl/10.antialiasing/shaders/screen.frag
new file mode 100644
index 0000000..5ccc843
--- /dev/null
+++ b/advanced_opengl/10.antialiasing/shaders/screen.frag
@@ -0,0 +1,110 @@
+#version 330 core
+
+out vec4 frag_color;
+
+in vec2 tex_coords;
+
+uniform sampler2D texture1;
+
+vec4 inversion()
+{
+    vec4 result = vec4(1.0-vec3(texture(texture1, tex_coords)), 1.0);
+    return(result);
+}
+
+vec4 grayscale_average()
+{
+    vec4 tex_color = texture(texture1, tex_coords);
+    float average = (tex_color.r+tex_color.g+tex_color.b)/3.0;
+    vec4 result = vec4(average, average, average, 1.0);
+    return(result);
+}
+
+vec4 grayscale_weights()
+{
+    vec4 tex_color = texture(texture1, tex_coords);
+    float average = 0.2126*tex_color.r+0.7152*tex_color.g+0.0722*tex_color.b;
+    vec4 result = vec4(average, average, average, 1.0);
+    return(result);
+}
+
+const float offset = 1.0/300.0;
+
+vec4 kernel_effect(float[9] kernel)
+{
+    vec2 offsets[9] = vec2[](
+        vec2(-offset, offset), /* top-left */
+        vec2(0.0, offset), /* top-center */
+        vec2(offset, offset), /* top-right */
+        vec2(-offset, 0.0), /* center-left */
+        vec2(0.0, 0.0), /* center-center */
+        vec2(offset, 0.0), /* center-right */
+        vec2(-offset, -offset), /* bottom-left */
+        vec2(0.0, -offset), /* bottom-center */
+        vec2(offset, -offset) /* bottom-right */
+    );
+
+    vec3 sample_texture[9];
+    for (int i = 0; i < 9; ++i)
+        sample_texture[i] = vec3(texture(texture1, tex_coords+offsets[i]));
+
+    vec3 color = vec3(0.0);
+    for (int i = 0; i < 9; ++i)
+        color += sample_texture[i]*kernel[i];
+
+    return(vec4(color, 1.0));
+}
+
+void
+main(void)
+{
+    float strange_kernel[9] = float[](
+        -1, -1, -1,
+        -1,  9, -1,
+        -1, -1, -1
+    );
+
+    float gaussian_blur_kernel[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
+    );
+
+    float box_blur_kernel[9] = float[](
+        1.0/9.0, 1.0/9.0, 1.0/9.0,
+        1.0/9.0, 1.0/9.0, 1.0/9.0,
+        1.0/9.0, 1.0/9.0, 1.0/9.0
+    );
+
+    float edge_detection_kernel[9] = float[](
+        1.0,  1.0,  1.0,
+        1.0, -8.0,  1.0,
+        1.0,  1.0,  1.0
+    );
+
+    float sharpening_kernel[9] = float[](
+         0.0, -1.0,  0.0,
+        -1.0,  5.0, -1.0,
+         0.0, -1.0,  0.0
+    );
+
+    float sobel_kernel_vertical[9] = float[](
+        -1.0, 0.0, 1.0,
+        -2.0, 0.0, 2.0,
+        -1.0, 0.0, 0.0
+    );
+    float sobel_kernel_horizontal[9] = float[](
+        -1.0, -2.0, -1.0,
+         0.0,  0.0,  0.0,
+         1.0,  2.0,  1.0
+    );
+
+    float funny_kernel[9] = float[](
+        1.0,  1.0,  1.0,
+        1.0, -4.0,  1.0,
+        1.0,  1.0,  1.0
+    );
+
+    frag_color = kernel_effect(funny_kernel);
+    frag_color *= vec4(0.76, 0.47, 0.84, 1.0);
+}