Skybox

core/Shaders/SkyboxShader.cpp

@@ -0,0 +1,12 @@
+#include "SkyboxShader.h"
+#include "skybox.vert.h"
+#include "skybox.frag.h"
+
+SkyboxShader::SkyboxShader() : Shader(skybox_vert, skybox_frag) {}
+
+void SkyboxShader::UpdateSkybox(Skybox skybox) {
+  glActiveTexture(GL_TEXTURE0);
+  glBindTexture(GL_TEXTURE_CUBE_MAP, skybox.id);
+}
+
+Name SkyboxShader::GetName() const { return "Skybox Shader"; }

core/Shaders/SkyboxShader.h

@@ -0,0 +1,14 @@
+#ifndef SKYBOXSHADER_H
+#define SKYBOXSHADER_H
+
+#include "Shader.h"
+#include "Skybox.h"
+
+class SkyboxShader : public Shader {
+public:
+  SkyboxShader();
+  Name GetName() const;
+  void UpdateSkybox(Skybox skybox);
+};
+
+#endif /* SKYBOXSHADER_H */

core/Skybox.cpp

@@ -0,0 +1,94 @@
+#include "Skybox.h"
+
+cfloat vertices[] = {
+    // positions          
+    -1.0f,  1.0f, -1.0f,
+    -1.0f, -1.0f, -1.0f,
+     1.0f, -1.0f, -1.0f,
+     1.0f, -1.0f, -1.0f,
+     1.0f,  1.0f, -1.0f,
+    -1.0f,  1.0f, -1.0f,
+
+    -1.0f, -1.0f,  1.0f,
+    -1.0f, -1.0f, -1.0f,
+    -1.0f,  1.0f, -1.0f,
+    -1.0f,  1.0f, -1.0f,
+    -1.0f,  1.0f,  1.0f,
+    -1.0f, -1.0f,  1.0f,
+
+     1.0f, -1.0f, -1.0f,
+     1.0f, -1.0f,  1.0f,
+     1.0f,  1.0f,  1.0f,
+     1.0f,  1.0f,  1.0f,
+     1.0f,  1.0f, -1.0f,
+     1.0f, -1.0f, -1.0f,
+
+    -1.0f, -1.0f,  1.0f,
+    -1.0f,  1.0f,  1.0f,
+     1.0f,  1.0f,  1.0f,
+     1.0f,  1.0f,  1.0f,
+     1.0f, -1.0f,  1.0f,
+    -1.0f, -1.0f,  1.0f,
+
+    -1.0f,  1.0f, -1.0f,
+     1.0f,  1.0f, -1.0f,
+     1.0f,  1.0f,  1.0f,
+     1.0f,  1.0f,  1.0f,
+    -1.0f,  1.0f,  1.0f,
+    -1.0f,  1.0f, -1.0f,
+
+    -1.0f, -1.0f, -1.0f,
+    -1.0f, -1.0f,  1.0f,
+     1.0f, -1.0f, -1.0f,
+     1.0f, -1.0f, -1.0f,
+    -1.0f, -1.0f,  1.0f,
+     1.0f, -1.0f,  1.0f
+};
+
+Skybox::Skybox() {
+  glGenVertexArrays(1, &cube);
+  glBindVertexArray(cube);
+
+  Id vbo;
+  glGenBuffers(1, &vbo);
+  glBindBuffer(GL_ARRAY_BUFFER, vbo);
+  glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+
+  // We're just going to use position data
+  // UV data is the same
+  glEnableVertexAttribArray(0);
+  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * (sizeof(cfloat)), (void*) 0);
+  glBindVertexArray(0);
+}
+
+Name Skybox::GetType() const { return "Skybox"; }
+
+Skybox *Skybox::FromFiles(const char *right, const char* left, const char* top, const char* bottom, const char* front, const char* back) {
+  // HOCUS: https://learnopengl.com/Advanced-OpenGL/Cubemaps
+  Skybox *sb = new Skybox();
+  glGenTextures(1, &sb->id);
+  glBindTexture(GL_TEXTURE_CUBE_MAP, sb->id);
+
+  int width, height, nrChannels;
+  unsigned char* data;
+  const char* files[] = {right, left, top, bottom, front, back};
+  for (int i = 0; i < 6; i++) {
+    data = stbi_load(files[i], &width, &height, &nrChannels, 3);
+    glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i,
+		 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
+    stbi_image_free(data);
+  }
+  glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+  glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+  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);
+
+  return sb;
+}
+
+void Skybox::DrawSkybox() {
+  glBindVertexArray(cube);
+  glDrawArrays(GL_TRIANGLES, 0, 36);
+  glBindVertexArray(0);
+}

core/Skybox.h

@@ -0,0 +1,21 @@
+#ifndef SKYBOX_H
+#define SKYBOX_H
+
+#include <GL/glew.h>
+
+#include "types.h"
+#include "Node.h"
+#include "Material.h"
+
+class Skybox : public Node {
+public:
+  Skybox();
+  virtual Name GetType() const;
+  static Skybox *FromFiles(const char *right, const char* left, const char* top, const char* bottom, const char* front, const char* back);
+  void DrawSkybox();
+  Id id;
+private:
+  Id cube;
+};
+
+#endif /* SKYBOX_H */

core/couch.cpp

@@ -12,6 +12,7 @@
 
 #include "Shaders/FlatShader.h"
 #include "Shaders/ScreenShader.h"
+#include "Shaders/SkyboxShader.h"
 
 #include "Screen.h"
 
@@ -20,6 +21,8 @@
 #include "Node.h"
 #include "Mesh.h"
 #include "Light.h"
+#include "Skybox.h"
+
 #include "Scripting/Lua.h"
 
 // Thirdparty Includes
@@ -88,6 +91,8 @@ int main() {
   Screen screen;
   ScreenShader *screenShader = new ScreenShader();
 
+  SkyboxShader *skyboxShader = new SkyboxShader();
+  
   FlatShader *shader = new FlatShader();
   
   Matrix projection = glm::perspective(glm::radians(45.0f), 800.0f/600.0f, 0.1f, 100.0f);
@@ -127,6 +132,18 @@ int main() {
     // Render the scene tree
     render(root, shader, Matrix(1.0f));
 
+    // Render the skybox
+    Skybox *skybox = Util::FindNodeByType<Skybox>(root, "Skybox");
+    if (skybox) {
+      glDepthFunc(GL_LEQUAL);
+      skyboxShader->Use();
+      skyboxShader->UpdateView(glm::mat4(glm::mat3(view)));
+      skyboxShader->UpdateProjection(projection);
+      skyboxShader->UpdateSkybox(*skybox);
+      skybox->DrawSkybox();
+      glDepthFunc(GL_LESS);
+    }
+
     // Stop rendering to texture
     screen.Disable();
     // // Render the screen

demo/main.lua

@@ -36,6 +36,16 @@ function init()
    light.specular = 0.1
    couch.Node.GetRoot().children:Append(light)
 
+   skybox = couch.Skybox.FromFiles(
+      "skybox/right.jpg",
+      "skybox/left.jpg",
+      "skybox/top.jpg",
+      "skybox/bottom.jpg",
+      "skybox/front.jpg",
+      "skybox/back.jpg"
+   )
+   couch.Node.GetRoot().children:Append(skybox)
+   
    ball = couch.Mesh.FromFile("cube.obj")
    material = ball:GetMaterial(0)
    material.ambient = RED
@@ -44,6 +54,7 @@ function init()
    couch.Node.GetRoot().children:Append(ball)
    
    ball1 = couch.Mesh.FromFile("ball.obj")
+   
    print(material.diffuse.b)
    material = ball1:GetMaterial(0)
    ball1:SetMaterial(0, material)

scripting/couch.i

@@ -15,6 +15,7 @@
 #include "Material.h"
 #include "Camera.h"
 #include "Light.h"
+#include "Skybox.h"
 %}
 
 %rename("%(strip:[script_])s") "";
@@ -45,7 +46,6 @@ public:
   }
 }
 
-
 %include "types.h"
 %include "constants.h"
 %include "Node.h"
@@ -55,4 +55,4 @@ public:
 %include "Material.h"
 %include "Camera.h"
 %include "Light.h"
-
+%include "Skybox.h"

shaders/CMakeLists.txt

@@ -12,7 +12,9 @@ add_shader(flat.vert)
 add_shader(flat.frag)
 add_shader(screen.vert)
 add_shader(screen.frag)
+add_shader(skybox.vert)
+add_shader(skybox.frag)
 
 add_custom_target(shader_headers
-  DEPENDS flat.vert.h flat.frag.h screen.vert.h screen.frag.h
+  DEPENDS flat.vert.h flat.frag.h screen.vert.h screen.frag.h skybox.vert.h skybox.frag.h
   COMMENT "Generated shaders headers.")

shaders/skybox.frag

@@ -0,0 +1,11 @@
+#version 330 core
+
+out vec4 FragColor;
+
+in vec3 UV;
+
+uniform samplerCube skybox;
+
+void main() {
+  FragColor = texture(skybox, UV);
+}

shaders/skybox.vert

@@ -0,0 +1,14 @@
+#version 330 core
+
+layout (location = 0) in vec3 pos;
+
+out vec3 UV;
+
+uniform mat4 VIEW; // Assuming this is free of translation
+uniform mat4 PROJECTION;
+
+void main() {
+  UV = pos;
+  vec4 projectedPos = PROJECTION * VIEW * vec4(pos, 1.0);
+  gl_Position = projectedPos.xyww;
+}