4 files changed, 163 insertions, 0 deletions
diff --git a/advanced_opengl/5.framebuffers/shaders/cube.fs b/advanced_opengl/5.framebuffers/shaders/cube.fs
new file mode 100644
index 0000000..f58c5d3
--- /dev/null
+++ b/advanced_opengl/5.framebuffers/shaders/cube.fs
@@ -0,0 +1,13 @@
+#version 330 core
+
+out vec4 frag_color;
+
+in vec2 tex_coords;
+
+uniform sampler2D texture1;
+
+void
+main(void)
+{
+    frag_color = texture(texture1, tex_coords);
+}
diff --git a/advanced_opengl/5.framebuffers/shaders/cube.vs b/advanced_opengl/5.framebuffers/shaders/cube.vs
new file mode 100644
index 0000000..3c11932
--- /dev/null
+++ b/advanced_opengl/5.framebuffers/shaders/cube.vs
@@ -0,0 +1,17 @@
+#version 330 core
+
+layout(location = 0) in vec3 apos;
+layout(location = 1) in vec2 atex_coords;
+
+uniform mat4 model;
+uniform mat4 view;
+uniform mat4 projection;
+
+out vec2 tex_coords;
+
+void
+main(void)
+{
+    gl_Position = projection*view*model*vec4(apos, 1.0f);
+    tex_coords = atex_coords;
+}
diff --git a/advanced_opengl/5.framebuffers/shaders/screen.fs b/advanced_opengl/5.framebuffers/shaders/screen.fs
new file mode 100644
index 0000000..8f0b2da
--- /dev/null
+++ b/advanced_opengl/5.framebuffers/shaders/screen.fs
@@ -0,0 +1,119 @@
+#version 330 core
+
+out vec4 frag_color;
+
+in vec2 tex_coords;
+
+uniform sampler2D texture1;
+
+vec4
+inversion()
+{
+    vec4 result = vec4(1.0f-vec3(texture(texture1, tex_coords)), 1.0f);
+    return(result);
+}
+
+vec4
+grayscale_average()
+{
+    vec4 tex_color = texture(texture1, tex_coords);
+    float average = (tex_color.r+tex_color.g+tex_color.b)/3.0f;
+    vec4 result = vec4(average, average, average, 1.0f);
+    return(result);
+}
+
+vec4
+grayscale_weights()
+{
+    vec4 tex_color = texture(texture1, tex_coords);
+    float average = 0.2126*tex_color.r+0.7152*tex_color.g+0.0722f*tex_color.b;
+    vec4 result = vec4(average, average, average, 1.0f);
+    return(result);
+}
+
+const float offset = 1.0f/300.0f;
+
+vec4
+kernel_effect(float[9] kernel)
+{
+    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 */
+    );
+
+    vec3 sample_texture[9];
+    for (int offset_index = 0;
+         offset_index < 9;
+         ++offset_index)
+    {
+        sample_texture[offset_index] =
+            vec3(texture(texture1, tex_coords+offsets[offset_index]));
+    }
+
+    vec3 color = vec3(0.0f);
+    for (int i = 0; i < 9; ++i)
+        color += sample_texture[i]*kernel[i];
+
+    return(vec4(color, 1.0f));
+}
+
+void
+main(void)
+{
+    float strange_kernel[9] = float[](
+        -1, -1, -1,
+        -1,  9, -1,
+        -1, -1, -1
+    );
+
+    float gaussian_blur_kernel[9] = float[](
+        1.0f/16.0f, 2.0f/16.0f, 1.0f/16.0f,
+        2.0f/16.0f, 4.0f/16.0f, 2.0f/16.0f,
+        1.0f/16.0f, 2.0f/16.0f, 1.0f/16.0f
+    );
+
+    float box_blur_kernel[9] = float[](
+        1.0f/9.0f, 1.0f/9.0f, 1.0f/9.0f,
+        1.0f/9.0f, 1.0f/9.0f, 1.0f/9.0f,
+        1.0f/9.0f, 1.0f/9.0f, 1.0f/9.0f
+    );
+
+    float edge_detection_kernel[9] = float[](
+        1.0f,  1.0f,  1.0f,
+        1.0f, -8.0f,  1.0f,
+        1.0f,  1.0f,  1.0f
+    );
+
+    float sharpening_kernel[9] = float[](
+         0.0f, -1.0f,  0.0f,
+        -1.0f,  5.0f, -1.0f,
+         0.0f, -1.0f,  0.0f
+    );
+
+    float sobel_kernel_vertical[9] = float[](
+        -1.0f, 0.0f, 1.0f,
+        -2.0f, 0.0f, 2.0f,
+        -1.0f, 0.0f, 0.0f
+    );
+    float sobel_kernel_horizontal[9] = float[](
+        -1.0f, -2.0f, -1.0f,
+         0.0f,  0.0f,  0.0f,
+         1.0f,  2.0f,  1.0f
+    );
+
+    float funny_kernel[9] = float[](
+        1.0f,  1.0f,  1.0f,
+        1.0f, -4.0f,  1.0f,
+        1.0f,  1.0f,  1.0f
+    );
+
+    frag_color = kernel_effect(funny_kernel);
+    frag_color *= vec4(0.76f, 0.47f, 0.84f, 1.0f);
+}
diff --git a/advanced_opengl/5.framebuffers/shaders/screen.vs b/advanced_opengl/5.framebuffers/shaders/screen.vs
new file mode 100644
index 0000000..157dde2
--- /dev/null
+++ b/advanced_opengl/5.framebuffers/shaders/screen.vs
@@ -0,0 +1,14 @@
+#version 330 core
+layout(location = 0) in vec3 apos;
+layout(location = 1) in vec2 atex_coords;
+
+out vec2 tex_coords;
+
+uniform mat4 model;
+
+void
+main(void)
+{
+    gl_Position = model*vec4(apos, 1.0f);
+    tex_coords = atex_coords;
+}