From a9a7422a1936ed360bf06339bfaa1fb5a0e24ad6 Mon Sep 17 00:00:00 2001
From: maelstrom <maelstrom@maelstrom.dev>
Date: Tue, 15 Oct 2024 18:42:55 +0200
Subject: [PATCH] skybox loading code

---
 assets/shaders/skybox.fs |  2 +-
 assets/shaders/skybox.vs |  2 +-
 src/rendering/skybox.cpp | 47 ++++++++++++++++++++++++++++++++++++++++
 src/rendering/skybox.h   | 15 +++++++++++++
 4 files changed, 64 insertions(+), 2 deletions(-)
 create mode 100644 src/rendering/skybox.cpp
 create mode 100644 src/rendering/skybox.h

diff --git a/assets/shaders/skybox.fs b/assets/shaders/skybox.fs
index f2a6016..d6f55b1 100644
--- a/assets/shaders/skybox.fs
+++ b/assets/shaders/skybox.fs
@@ -11,5 +11,5 @@ out vec4 fColor;
 // Main
 
 void main() {
-    fColor = vec4(vTexCoords, 1.0, 1.0);
+    fColor = texture(uTexture, vTexCoords);
 }
diff --git a/assets/shaders/skybox.vs b/assets/shaders/skybox.vs
index b140237..0cc797e 100644
--- a/assets/shaders/skybox.vs
+++ b/assets/shaders/skybox.vs
@@ -12,7 +12,7 @@ uniform mat4 projection;
 
 void main()
 {
-    gl_Position = projection * vec4(vec3(view * vec4(aPos, 0.0)), 1.0);
+    gl_Position = projection * view * vec4(aPos, 1.0);
     vPos = vec3(vec4(aPos, 1.0));
     vNormal = aNormal;
     vTexCoords = aTexCoords;
diff --git a/src/rendering/skybox.cpp b/src/rendering/skybox.cpp
new file mode 100644
index 0000000..f7d3caa
--- /dev/null
+++ b/src/rendering/skybox.cpp
@@ -0,0 +1,47 @@
+#include <GL/glew.h>
+#include <GL/gl.h>
+#include <stb/stb_image.h>
+
+#include "skybox.h"
+
+Skybox::Skybox(std::vector<std::string> faces, unsigned int format) {
+    glGenTextures(1, &this->ID);
+    glBindTexture(GL_TEXTURE_CUBE_MAP, this->ID);
+
+    // Wrapping
+    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
+
+    // Interpolation
+    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+    // stbi_set_flip_vertically_on_load(true);
+    for (unsigned int i = 0; i< faces.size(); i++) {
+        int width, height, nrChannels;
+        unsigned char *data = stbi_load(faces[i].c_str(), &width, &height,
+                                        &nrChannels, 0);
+
+        if (!data) {
+            printf("Failed to load texture '%s'\n", faces[i].c_str());
+            abort();
+        }
+
+        glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, format, width, height, 0, format,
+                    GL_UNSIGNED_BYTE, data);
+        glGenerateMipmap(GL_TEXTURE_2D);
+    
+
+        stbi_image_free(data);
+    }
+}
+
+Skybox::~Skybox() {
+    glDeleteTextures(1, &this->ID);
+}
+
+void Skybox::activate(unsigned int textureIdx) {
+    glActiveTexture(GL_TEXTURE0 + textureIdx);
+    glBindTexture(GL_TEXTURE_2D, this->ID);
+}
diff --git a/src/rendering/skybox.h b/src/rendering/skybox.h
new file mode 100644
index 0000000..5934cb7
--- /dev/null
+++ b/src/rendering/skybox.h
@@ -0,0 +1,15 @@
+#pragma once
+
+#include <string>
+#include <vector>
+#define GL_RGB 0x1907
+
+class Skybox {
+private:
+    unsigned int ID;
+public:
+    Skybox(std::vector<std::string>, unsigned format = GL_RGB);
+    ~Skybox();
+
+    void activate(unsigned int textureIdx);
+};