From 79e2a02bff3ab5a3a0f0fabc8ecaa639e3956e8e Mon Sep 17 00:00:00 2001
From: griffi-gh <prasol258@gmail.com>
Date: Sun, 15 Jan 2023 03:26:18 +0100
Subject: [PATCH] shaders

---
 src/game.rs         | 17 ++++++++++++-
 src/game/camera.rs  | 35 ++++++++++++++++++++++++++
 src/game/shaders.rs | 61 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 112 insertions(+), 1 deletion(-)
 create mode 100644 src/game/camera.rs
 create mode 100644 src/game/shaders.rs

diff --git a/src/game.rs b/src/game.rs
index 0325673..9ed082b 100644
--- a/src/game.rs
+++ b/src/game.rs
@@ -1,4 +1,4 @@
-use glium::Surface;
+use glium::{Surface, uniform};
 use glutin::{
     event::{Event, WindowEvent},
     event_loop::{EventLoop, ControlFlow},
@@ -6,23 +6,37 @@ use glutin::{
 
 mod assets;
 mod display;
+mod shaders;
+mod camera;
 
 use assets::Assets;
 use display::init_display;
+use shaders::{Programs, Colored2dVertex};
 
 pub fn run() {
     log::info!("starting up");
     let event_loop = EventLoop::new();
     log::info!("initializing display");
     let display = init_display(&event_loop);
+    log::info!("compiling shaders");
+    let programs = Programs::compile_all(&display);
     log::info!("loading assets");
     let assets = Assets::load_all_sync(&display);
     log::info!("game loaded");
 
+    //=======================
+    let vertex1 = Colored2dVertex { position: [-0.5, -0.5] };
+    let vertex2 = Colored2dVertex { position: [ 0.0,  0.5] };
+    let vertex3 = Colored2dVertex { position: [ 0.5, -0.25] };
+    let shape = vec![vertex1, vertex2, vertex3];
+    let vertex_buffer = glium::VertexBuffer::new(&display, &shape).unwrap();
+    //=======================
+
     event_loop.run(move |ev, _, control_flow| {
         match ev {
             Event::WindowEvent { event, .. } => match event {
                 WindowEvent::CloseRequested => {
+                    log::info!("exit requested");
                     *control_flow = ControlFlow::Exit;
                     return
                 },
@@ -32,6 +46,7 @@ pub fn run() {
         }
         let mut target = display.draw();
         target.clear_color_and_depth((0.5, 0.5, 1., 1.), 1.);
+        target.draw(&vertex_buffer, &glium::index::NoIndices(glium::index::PrimitiveType::TrianglesList), &programs.colored_2d, &uniform! { u_color: [1.0f32, 0.0f32, 0.0f32, 1.0f32] }, &Default::default()).unwrap();
         target.finish().unwrap();
     });
 }
diff --git a/src/game/camera.rs b/src/game/camera.rs
new file mode 100644
index 0000000..31c91e8
--- /dev/null
+++ b/src/game/camera.rs
@@ -0,0 +1,35 @@
+// https://glium.github.io/glium/book/tuto-12-camera.html
+
+fn view_matrix(position: &[f32; 3], direction: &[f32; 3], up: &[f32; 3]) -> [[f32; 4]; 4] {
+    let f = {
+        let f = direction;
+        let len = f[0] * f[0] + f[1] * f[1] + f[2] * f[2];
+        let len = len.sqrt();
+        [f[0] / len, f[1] / len, f[2] / len]
+    };
+
+    let s = [up[1] * f[2] - up[2] * f[1],
+             up[2] * f[0] - up[0] * f[2],
+             up[0] * f[1] - up[1] * f[0]];
+
+    let s_norm = {
+        let len = s[0] * s[0] + s[1] * s[1] + s[2] * s[2];
+        let len = len.sqrt();
+        [s[0] / len, s[1] / len, s[2] / len]
+    };
+
+    let u = [f[1] * s_norm[2] - f[2] * s_norm[1],
+             f[2] * s_norm[0] - f[0] * s_norm[2],
+             f[0] * s_norm[1] - f[1] * s_norm[0]];
+
+    let p = [-position[0] * s_norm[0] - position[1] * s_norm[1] - position[2] * s_norm[2],
+             -position[0] * u[0] - position[1] * u[1] - position[2] * u[2],
+             -position[0] * f[0] - position[1] * f[1] - position[2] * f[2]];
+
+    [
+        [s_norm[0], u[0], f[0], 0.0],
+        [s_norm[1], u[1], f[1], 0.0],
+        [s_norm[2], u[2], f[2], 0.0],
+        [p[0], p[1], p[2], 1.0],
+    ]
+}
diff --git a/src/game/shaders.rs b/src/game/shaders.rs
new file mode 100644
index 0000000..58f6345
--- /dev/null
+++ b/src/game/shaders.rs
@@ -0,0 +1,61 @@
+use glium::{Display, Program, implement_vertex};
+
+pub struct Programs {
+    pub colored_2d: Program,
+}
+impl Programs {
+    pub fn compile_all(display: &Display) -> Self {
+        Self {
+            colored_2d: Program::from_source(display, COLORED_2D_VERTEX_SHADER, COLORED_2D_FRAGMENT_SHADER, None).unwrap(),
+        }
+    }
+}
+
+#[derive(Clone, Copy)]
+pub struct Colored2dVertex {
+    pub position: [f32; 2]
+}
+implement_vertex!(Colored2dVertex, position);
+
+pub const COLORED_2D_VERTEX_SHADER: &str = r#"
+    #version 140
+
+    in vec2 position;
+
+    void main() {
+        gl_Position = vec4(position, 0., 1.);
+    }
+"#;
+pub const COLORED_2D_FRAGMENT_SHADER: &str = r#"
+    #version 140
+
+    out vec4 color;
+    uniform vec4 u_color;
+
+    void main() {
+        color = u_color;
+    }
+"#;
+
+//TODO store vertex data in a more compact way
+pub const CHUNK_VERTEX_SHADER: &str = r#"
+    #version 150
+
+    in vec3 position;
+    in vec3 normal;
+
+    out vec3 v_normal;
+
+    uniform mat4 perspective;
+    uniform mat4 view;
+    uniform mat4 model;
+
+    void main() {
+        mat4 modelview = view * model;
+        v_normal = transpose(inverse(mat3(modelview))) * normal;
+        gl_Position = perspective * modelview * vec4(position, 1.0);
+    }
+"#;
+pub const CHUNK_FRAGMENT_SHADER: &str = r#"
+    #version 150
+"#;