From 27e34a18c9c44c2738111bf15494cb6ecf0d1726 Mon Sep 17 00:00:00 2001
From: "Zed A. Shaw" <zed.shaw@gmail.com>
Date: Tue, 1 Sep 2026 13:20:58 -0400
Subject: [PATCH] Have framebuffer mostly working, but light calculations are
 not there.

---
 21-framebuffers/config.json                   |  8 ++---
 .../shaders/21-framebuffers.frag.glsl         | 11 +++++++
 .../shaders/21-framebuffers.vert.glsl         | 20 +++++++++++++
 21-framebuffers/src/scene.cpp                 |  1 +
 21-framebuffers/src/scene.hpp                 | 29 ++++++++++---------
 5 files changed, 50 insertions(+), 19 deletions(-)
 create mode 100644 21-framebuffers/shaders/21-framebuffers.frag.glsl
 create mode 100644 21-framebuffers/shaders/21-framebuffers.vert.glsl

diff --git a/21-framebuffers/config.json b/21-framebuffers/config.json
index b80fd17..ea49535 100644
--- a/21-framebuffers/config.json
+++ b/21-framebuffers/config.json
@@ -1,12 +1,8 @@
 {
   "scene": {
     "shader": {
-      "vertex_path": "shaders/19-vert.glsl",
-      "frag_path": "shaders/19-frag.glsl"
-    },
-    "light_shader": {
-      "vertex_path": "shaders/19-vert.glsl",
-      "frag_path": "shaders/19-lightsource.frag.glsl"
+      "vertex_path": "shaders/21-framebuffers.vert.glsl",
+      "frag_path": "shaders/21-framebuffers.frag.glsl"
     },
     "screen_shader": {
       "vertex_path": "shaders/21-screen.vert.glsl",
diff --git a/21-framebuffers/shaders/21-framebuffers.frag.glsl b/21-framebuffers/shaders/21-framebuffers.frag.glsl
new file mode 100644
index 0000000..f25434c
--- /dev/null
+++ b/21-framebuffers/shaders/21-framebuffers.frag.glsl
@@ -0,0 +1,11 @@
+#version 330 core
+out vec4 FragColor;
+
+in vec2 TexCoords;
+
+uniform sampler2D texture1;
+
+void main()
+{
+    FragColor = texture(texture1, TexCoords);
+}
diff --git a/21-framebuffers/shaders/21-framebuffers.vert.glsl b/21-framebuffers/shaders/21-framebuffers.vert.glsl
new file mode 100644
index 0000000..276f393
--- /dev/null
+++ b/21-framebuffers/shaders/21-framebuffers.vert.glsl
@@ -0,0 +1,20 @@
+#version 330 core
+layout (location = 0) in vec3 aPos;
+layout (location = 1) in vec3 aNormal;
+layout (location = 2) in vec2 aTexCoords;
+
+out vec3 FragPos;
+out vec3 Normal;
+out vec2 TexCoords;
+
+uniform mat4 model;
+uniform mat4 view;
+uniform mat4 projection;
+
+void main()
+{
+    gl_Position = projection * view * model * vec4(aPos, 1.0f);
+    FragPos = vec3(model * vec4(aPos, 1.0));
+    Normal = mat3(transpose(inverse(model))) * aNormal;
+    TexCoords = aTexCoords;
+}
diff --git a/21-framebuffers/src/scene.cpp b/21-framebuffers/src/scene.cpp
index c9cd9d9..f0a825b 100644
--- a/21-framebuffers/src/scene.cpp
+++ b/21-framebuffers/src/scene.cpp
@@ -43,6 +43,7 @@ void Scene::render(GLFWwindow* window) {
   // framebuffer stuff here
   glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
   glEnable(GL_DEPTH_TEST);
+
   glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
diff --git a/21-framebuffers/src/scene.hpp b/21-framebuffers/src/scene.hpp
index 983ed11..c636865 100644
--- a/21-framebuffers/src/scene.hpp
+++ b/21-framebuffers/src/scene.hpp
@@ -81,22 +81,32 @@ struct Scene {
           thing.scale);
     }
 
-    // screen quadVAO
     glGenVertexArrays(1, &quadVAO);
     glGenBuffers(1, &quadVBO);
     glBindVertexArray(quadVAO);
     glBindBuffer(GL_ARRAY_BUFFER, quadVBO);
     glBufferData(GL_ARRAY_BUFFER, sizeof(quadVertices), &quadVertices, GL_STATIC_DRAW);
     glEnableVertexAttribArray(0);
-    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)0);
+    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void *)0);
     glEnableVertexAttribArray(1);
     glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)(2 * sizeof(float)));
 
+    shader.use();
+    shader.setInt("texture1", 0);
+    shader.apply_lighting(light);
+
+    screen_shader.use();
+    screen_shader.setInt("screenTexture", 0);
 
     // framebuffer config
     glGenFramebuffers(1, &framebuffer);
     glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
 
+    // framebuffer configuration
+    // -------------------------
+    glGenFramebuffers(1, &framebuffer);
+    glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
+
     // create a color attachment texture
     glGenTextures(1, &textureColorBuffer);
     glBindTexture(GL_TEXTURE_2D, textureColorBuffer);
@@ -105,22 +115,15 @@ struct Scene {
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
     glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, textureColorBuffer, 0);
 
-    // create renderbuffer object for depth and stencil attachment
+    // create a renderbuffer object for depth and stencil attachment (we won't be sampling these)
     glGenRenderbuffers(1, &rbo);
     glBindRenderbuffer(GL_RENDERBUFFER, rbo);
-    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, SCR_WIDTH, SCR_HEIGHT);
-    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, rbo);
-
-    glBindRenderbuffer(GL_RENDERBUFFER, 0);
+    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, SCR_WIDTH, SCR_HEIGHT); // use a single renderbuffer object for both a depth AND stencil buffer.
+    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, rbo); // now actually attach it
+    // now that we actually created the framebuffer and added all attachments we want to check if it is actually complete now
 
     dbc::check(glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE, "Frame buffer not complete.");
     glBindFramebuffer(GL_FRAMEBUFFER, 0);
-
-    shader.use();
-    shader.apply_lighting(light);
-
-    screen_shader.use();
-    screen_shader.setInt("screenTexture", 0);
   }
 
   void update();