From 68c3728dae3408f6449c78882e36defd2978b716 Mon Sep 17 00:00:00 2001
From: bnewbold <bnewbold@robocracy.org>
Date: Mon, 13 Jun 2016 23:50:48 -0400
Subject: exuberantplasma: simple new GLSL hack

---
 src/bin/exuberantplasma.rs | 134 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 134 insertions(+)
 create mode 100644 src/bin/exuberantplasma.rs

(limited to 'src')

diff --git a/src/bin/exuberantplasma.rs b/src/bin/exuberantplasma.rs
new file mode 100644
index 0000000..5d49a56
--- /dev/null
+++ b/src/bin/exuberantplasma.rs
@@ -0,0 +1,134 @@
+
+extern crate exuberant;
+extern crate getopts;
+
+#[macro_use]
+extern crate glium; 
+
+use exuberant::ExuberantHack;
+use getopts::Options;
+use glium::Surface;
+
+#[derive(Copy, Clone)]
+struct Vertex {
+    position: [f32; 2],
+}
+implement_vertex!(Vertex, position);
+
+struct ExuberantPlasma {
+    display: glium::Display,
+    program: glium::Program,
+}
+ 
+impl ExuberantPlasma {
+
+    pub fn new(display: glium::Display) -> ExuberantPlasma {
+
+        let vertex_shader_src = r#" #version 140 
+            
+            in vec2 position;
+            out vec2 v_coords;
+
+            void main() {
+                v_coords = position;
+                gl_Position = vec4(position, 0.0, 1.0);
+            }
+        "#; 
+
+        // This fragment shader verbatim from:
+        // http://www.bidouille.org/prog/plasma
+        let fragment_shader_src = r#" #version 140
+
+            precision mediump float;
+            #define PI 3.1415926535897932384626433832795
+            
+            uniform float u_time;
+            uniform vec2 u_k;
+            varying vec2 v_coords;
+            
+            void main() {
+                float v = 0.0;
+                vec2 c = v_coords * u_k - u_k/2.0;
+                v += sin((c.x+u_time));
+                v += sin((c.y+u_time)/2.0);
+                v += sin((c.x+c.y+u_time)/2.0);
+                c += u_k/2.0 * vec2(sin(u_time/3.0), cos(u_time/2.0));
+                v += sin(sqrt(c.x*c.x+c.y*c.y+1.0)+u_time);
+                v = v/2.0;
+                vec3 col = vec3(1, sin(PI*v), cos(PI*v));
+                gl_FragColor = vec4(col*.5 + .5, 1);
+            }
+        "#;
+
+
+        let program = glium::Program::from_source(
+            &display,
+            vertex_shader_src,
+            fragment_shader_src,
+            None).unwrap();
+
+        ExuberantPlasma {
+            display: display,
+            program: program,
+        }
+    }
+}
+
+impl ExuberantHack for ExuberantPlasma {
+
+    fn draw_frame(&mut self, t: f64) -> Result<(), String> {
+
+        let vertex1 = Vertex { position: [-1.0, -1.0] };
+        let vertex2 = Vertex { position: [ 3.0, -1.0] };
+        let vertex3 = Vertex { position: [-1.0,  3.0] };
+        let shape = vec![vertex1, vertex2, vertex3];
+
+        let vertex_buffer = glium::VertexBuffer::new(&self.display, &shape).unwrap();
+
+        let indices = glium::index::NoIndices(glium::index::PrimitiveType::TrianglesList);
+
+        // Drawing Pipeline
+        let mut target = self.display.draw();
+
+        let uniforms = uniform! {
+            u_time: (t % (12.0 * 3.141592)) as f32,
+            u_k: [10.0 as f32, 10.0 as f32],
+        };
+
+        // Set black background
+        target.clear_color_and_depth((0.0, 0.0, 0.0, 1.0), 1.0);
+
+        let params = glium::DrawParameters {
+            .. Default::default()
+        };
+
+        target.draw(&vertex_buffer,
+                    &indices,
+                    &self.program,
+                    &uniforms,
+                    &params).unwrap();
+
+        target.finish().or(Err("Failure rendering".to_string()))
+    }
+
+    fn get_display(&self) -> &glium::Display {
+        &self.display
+    }
+}
+
+fn main() {
+
+    let mut opts = Options::new();
+    opts.optopt("c", "count", "how many cows? (1 to 9) (IGNORED)", "NUM");
+    opts.optopt("s", "speed", "how fast? ratio, with 1.0 as normal (IGNORED)", "NUM");
+    opts.optflag("", "wireframe", "wireframe mode (IGNORED)");
+
+    let conf = exuberant::main_helper(opts);
+    let dislpay = exuberant::make_display(&conf);
+    let mut hack = ExuberantPlasma::new(dislpay);
+
+    // Here is where you would configure the hack based on command line options
+
+    // Ok, actually run it (loops forever)
+    exuberant::run(&mut hack, &conf);
+}
-- 
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