From dd39f4c31641d3723df4b9a45cb8fef9538fca64 Mon Sep 17 00:00:00 2001
From: Kjetil Orbekk <kjetil.orbekk@gmail.com>
Date: Sat, 11 Jun 2016 21:57:14 -0400
Subject: Use matrix uniform.

---
 rust/opengl/src/main.rs | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

(limited to 'rust/opengl')

diff --git a/rust/opengl/src/main.rs b/rust/opengl/src/main.rs
index ff24d1e..d7b3a52 100644
--- a/rust/opengl/src/main.rs
+++ b/rust/opengl/src/main.rs
@@ -11,8 +11,6 @@ fn main() {
         .build_glium()
         .unwrap();
 
-    // let display = glium::glutin::WindowBuilder::new().build_glium().unwrap();
-
     #[derive(Copy, Clone)]
     struct Vertex {
         position: [f32; 2],
@@ -31,11 +29,9 @@ fn main() {
     let vertex_shader_src = r#"
         #version 140
         in vec2 position;
-        uniform float t;
+        uniform mat4 trans;
         void main() {
-            vec2 p = position;
-            p.x += t;
-            gl_Position = vec4(p, 0.0, 1.0);
+            gl_Position = trans * vec4(position, 0.0, 1.0);
         }
     "#;
 
@@ -56,9 +52,18 @@ fn main() {
             t = -0.5;
         }
 
+        let uniforms = uniform! {
+            trans: [
+                [t.cos(),  t.sin(), 0.0, 0.0],
+                [-t.sin(), t.cos(), 0.0, 0.0],
+                [1.0,      0.0,     1.0, 0.0],
+                [t,        0.0,     0.0, 1.0f32],
+            ]
+        };
+
         let mut target = display.draw();
         target.clear_color(0.3, 0.3, 0.2, 1.0);
-        target.draw(&vertex_buffer, &indices, &program, &uniform! { t: t },
+        target.draw(&vertex_buffer, &indices, &program, &uniforms,
                     &Default::default()).unwrap();
         target.finish().unwrap();
 
@@ -69,5 +74,4 @@ fn main() {
             }
         }
     }
-
 }
-- 
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