Skybox

resources/shaders/skybox.fs

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

resources/shaders/skybox.vs

@@ -0,0 +1,14 @@
+#version 330 core
+layout (location = 0) in vec3 aPos;
+
+out vec3 TexCoords;
+
+uniform mat4 projection;
+uniform mat4 view;
+
+void main()
+{
+    TexCoords = aPos;
+    vec4 pos = projection * view * vec4(aPos, 1.0);
+    gl_Position = pos.xyww;
+}

src/example_client.rs

@@ -4,6 +4,7 @@ use crate::gaia::client::Client;
 use crate::gaia::components::{ModelComponent, Transform};
 use crate::gaia::consts;
 use crate::gaia::engine::Engine;
+use crate::gaia::sky::Sky;
 use crate::gaia::*;
 use cgmath::{perspective, vec3, Deg, Matrix4, Point3};
 use imgui_glfw_rs::glfw;
@@ -12,6 +13,7 @@ pub struct ExampleClient {
     models: Vec<ModelComponent>,
     camera: Camera,
     shader: shader::Shader,
+    sky: Sky,
     show_object_info: bool,
     show_camera_info: bool,
     object_info_id: i32,
@@ -19,6 +21,10 @@ pub struct ExampleClient {
 
 impl ExampleClient {
     pub fn create() -> ExampleClient {
+        let sky;
+        unsafe {
+            sky = Sky::new();
+        }
         ExampleClient {
             object_info_id: 0,
             show_camera_info: true,
@@ -37,6 +43,7 @@ impl ExampleClient {
                 "resources/shaders/model_loading.vs",
                 "resources/shaders/model_loading.fs",
             ),
+            sky: sky,
         }
     }
 }
@@ -60,10 +67,7 @@ impl Client for ExampleClient {
                 scale: vec3(2.5, 2.5, 2.5),
                 ..Transform::default()
             },
-            model: cache.get_model_ext(
+            model: cache.get_model_ext("resources/objects/tree/tree_6_d.obj", Some("tree_e.png")),
-                "resources/objects/tree/tree_6_d.obj",
-                Some("tree_e.png")
-            ),
         };
         let tree2 = ModelComponent {
             transform: Transform {
@@ -71,10 +75,7 @@ impl Client for ExampleClient {
                 scale: vec3(2.5, 2.5, 2.5),
                 ..Transform::default()
             },
-            model: cache.get_model_ext(
+            model: cache.get_model_ext("resources/objects/tree/tree_6_c.obj", Some("tree_e.png")),
-                "resources/objects/tree/tree_6_c.obj",
-                Some("tree_e.png")
-            ),
         };
         let tree3 = ModelComponent {
             transform: Transform {
@@ -82,10 +83,7 @@ impl Client for ExampleClient {
                 scale: vec3(2.5, 2.5, 2.5),
                 ..Transform::default()
             },
-            model: cache.get_model_ext(
+            model: cache.get_model_ext("resources/objects/tree/tree_6_c.obj", Some("tree_e.png")),
-                "resources/objects/tree/tree_6_c.obj",
-                Some("tree_e.png")
-            ),
         };
         self.models = vec![tree, tree2, tree3, ground, robot];
     }
@@ -107,6 +105,7 @@ impl Client for ExampleClient {
         for model in self.models.iter() {
             model.draw(&self.shader);
         }
+        self.sky.draw(view, projection);
     }
     fn update(&mut self, _engine: &mut Engine) {}
 

src/gaia/mod.rs

@@ -10,4 +10,5 @@ pub mod engine;
 pub mod mesh;
 pub mod model;
 pub mod shader;
+pub mod sky;
 pub mod utils;

src/gaia/sky.rs

@@ -0,0 +1,95 @@
+use crate::gaia::camera::*;
+use crate::gaia::shader::*;
+use crate::gaia::utils::*;
+use cgmath::Matrix4;
+use gl::types::*;
+use std::mem;
+use std::os::raw::c_void;
+use std::ptr;
+
+pub struct Sky {
+    shader: Shader,
+    texture_id: u32,
+    vao: u32,
+    vbo: u32,
+}
+
+impl Drop for Sky {
+    fn drop(&mut self) {
+        unsafe {
+            gl::DeleteVertexArrays(1, &self.vao);
+            gl::DeleteBuffers(1, &self.vbo);
+        }
+    }
+}
+
+impl Sky {
+    pub unsafe fn new() -> Sky {
+        let shader =
+            Shader::from_file("resources/shaders/skybox.vs", "resources/shaders/skybox.fs");
+
+        let skybox_vertices: [f32; 108] = [
+            // positions
+            -1.0, 1.0, -1.0, -1.0, -1.0, -1.0, 1.0, -1.0, -1.0, 1.0, -1.0, -1.0, 1.0, 1.0, -1.0,
+            -1.0, 1.0, -1.0, -1.0, -1.0, 1.0, -1.0, -1.0, -1.0, -1.0, 1.0, -1.0, -1.0, 1.0, -1.0,
+            -1.0, 1.0, 1.0, -1.0, -1.0, 1.0, 1.0, -1.0, -1.0, 1.0, -1.0, 1.0, 1.0, 1.0, 1.0, 1.0,
+            1.0, 1.0, 1.0, 1.0, -1.0, 1.0, -1.0, -1.0, -1.0, -1.0, 1.0, -1.0, 1.0, 1.0, 1.0, 1.0,
+            1.0, 1.0, 1.0, 1.0, 1.0, -1.0, 1.0, -1.0, -1.0, 1.0, -1.0, 1.0, -1.0, 1.0, 1.0, -1.0,
+            1.0, 1.0, 1.0, 1.0, 1.0, 1.0, -1.0, 1.0, 1.0, -1.0, 1.0, -1.0, -1.0, -1.0, -1.0, -1.0,
+            -1.0, 1.0, 1.0, -1.0, -1.0, 1.0, -1.0, -1.0, -1.0, -1.0, 1.0, 1.0, -1.0, 1.0,
+        ];
+
+        // skybox VAO
+        let (mut skybox_vao, mut skybox_vbo) = (0, 0);
+        gl::GenVertexArrays(1, &mut skybox_vao);
+        gl::GenBuffers(1, &mut skybox_vbo);
+        gl::BindVertexArray(skybox_vao);
+        gl::BindBuffer(gl::ARRAY_BUFFER, skybox_vbo);
+        gl::BufferData(
+            gl::ARRAY_BUFFER,
+            (skybox_vertices.len() * mem::size_of::<GLfloat>()) as GLsizeiptr,
+            &skybox_vertices[0] as *const f32 as *const c_void,
+            gl::STATIC_DRAW,
+        );
+        gl::EnableVertexAttribArray(0);
+        let stride = 3 * mem::size_of::<GLfloat>() as GLsizei;
+        gl::VertexAttribPointer(0, 3, gl::FLOAT, gl::FALSE, stride, ptr::null());
+
+        let faces = [
+            "resources/textures/skybox/right.jpg",
+            "resources/textures/skybox/left.jpg",
+            "resources/textures/skybox/top.jpg",
+            "resources/textures/skybox/bottom.jpg",
+            "resources/textures/skybox/back.jpg",
+            "resources/textures/skybox/front.jpg",
+        ];
+        let cubemap_texture = load_cubemap(&faces);
+        shader.use_program();
+        shader.setInt(c_str!("skybox"), 0);
+
+        Sky {
+            shader: shader,
+            texture_id: cubemap_texture,
+            vao: skybox_vao,
+            vbo: skybox_vbo,
+        }
+    }
+
+    pub unsafe fn draw(&mut self, mut view: Matrix4<f32>, projection: Matrix4<f32>) {
+        gl::DepthFunc(gl::LEQUAL); // change depth function so depth test passes when values are equal to depth buffer's content
+        self.shader.use_program();
+        // remove translation from the view matrix
+        view.w[0] = 0.0;
+        view.w[1] = 0.0;
+        view.w[2] = 0.0;
+        self.shader.set_mat4(c_str!("view"), &view);
+        self.shader.set_mat4(c_str!("projection"), &projection);
+        // skybox cube
+        gl::BindVertexArray(self.vao);
+        gl::ActiveTexture(gl::TEXTURE0);
+        gl::BindTexture(gl::TEXTURE_CUBE_MAP, self.texture_id);
+        gl::DrawArrays(gl::TRIANGLES, 0, 36);
+        gl::BindVertexArray(0);
+        gl::DepthFunc(gl::LESS); // set depth function back to default
+    }
+}

src/gaia/utils.rs

@@ -61,3 +61,67 @@ pub unsafe fn load_texture_from_dir(filename: &str, directory: &str) -> u32 {
 
     load_texture(&fullpath, format)
 }
+
+/// loads a cubemap texture from 6 individual texture faces
+/// order:
+/// +X (right)
+/// -X (left)
+/// +Y (top)
+/// -Y (bottom)
+/// +Z (front)
+/// -Z (back)
+/// -------------------------------------------------------
+pub unsafe fn load_cubemap(faces: &[&str]) -> u32 {
+    let mut texture_id = 0;
+    gl::GenTextures(1, &mut texture_id);
+    gl::BindTexture(gl::TEXTURE_CUBE_MAP, texture_id);
+
+    for (i, face) in faces.iter().enumerate() {
+        let (data, dim) = {
+            let img: ImagePtr<u8, Rgb> = io::read_u8(face).unwrap();
+            let img_data = img.data().to_vec();
+            let (x, y, _) = img.shape();
+
+            (img_data, (x as i32, y as i32))
+        };
+        gl::TexImage2D(
+            gl::TEXTURE_CUBE_MAP_POSITIVE_X + i as u32,
+            0,
+            gl::RGB as i32,
+            dim.0,
+            dim.1,
+            0,
+            gl::RGB,
+            gl::UNSIGNED_BYTE,
+            &data[0] as *const u8 as *const c_void,
+        );
+    }
+
+    gl::TexParameteri(
+        gl::TEXTURE_CUBE_MAP,
+        gl::TEXTURE_MIN_FILTER,
+        gl::LINEAR as i32,
+    );
+    gl::TexParameteri(
+        gl::TEXTURE_CUBE_MAP,
+        gl::TEXTURE_MAG_FILTER,
+        gl::LINEAR as i32,
+    );
+    gl::TexParameteri(
+        gl::TEXTURE_CUBE_MAP,
+        gl::TEXTURE_WRAP_S,
+        gl::CLAMP_TO_EDGE as i32,
+    );
+    gl::TexParameteri(
+        gl::TEXTURE_CUBE_MAP,
+        gl::TEXTURE_WRAP_T,
+        gl::CLAMP_TO_EDGE as i32,
+    );
+    gl::TexParameteri(
+        gl::TEXTURE_CUBE_MAP,
+        gl::TEXTURE_WRAP_R,
+        gl::CLAMP_TO_EDGE as i32,
+    );
+
+    texture_id
+}