[oogl] move the commonly-used example code into a module

crates/cardboard_oogl/examples/common.rs

@@ -0,0 +1,78 @@
+use sdl2::video::{GLProfile, Window};
+use std::rc::Rc;
+
+use cardboard_math::*;
+use cardboard_oogl::*;
+
+// <https://github.com/gfx-rs/wgpu-rs/blob/2ef725065e68164cced1551c7a2540523eb0ca77/examples/framework.rs#L336-L337>
+#[allow(dead_code)]
+fn main() {}
+
+pub fn prepare_example_gl_context(
+  example_name: &'static str,
+  window_size: Vec2u32,
+) -> (sdl2::Sdl, sdl2::VideoSubsystem, Window, sdl2::EventPump, SharedContext) {
+  let sdl_context = sdl2::init().unwrap();
+  let video_subsystem = sdl_context.video().unwrap();
+
+  let gl_attr = video_subsystem.gl_attr();
+  gl_attr.set_context_profile(GLProfile::GLES);
+  gl_attr.set_context_version(2, 0);
+
+  let window_title = format!("{} {} example", env!("CARGO_PKG_NAME"), example_name);
+  let window = video_subsystem
+    .window(&window_title, window_size.x, window_size.y)
+    .resizable()
+    .opengl()
+    .allow_highdpi()
+    .build()
+    .unwrap();
+
+  let sdl_gl_ctx = window.gl_create_context().unwrap();
+  let gl = Rc::new(Context::load_with(&video_subsystem, sdl_gl_ctx));
+
+  let event_pump = sdl_context.event_pump().unwrap();
+
+  (sdl_context, video_subsystem, window, event_pump, gl)
+}
+
+pub fn reset_gl_viewport(gl: &Context, window: &Window) {
+  let (w, h) = window.drawable_size();
+  gl.set_viewport(vec2(0, 0), vec2(w as i32, h as i32));
+}
+
+pub fn compile_shader(gl: SharedContext, src: &str, type_: ShaderType) -> Shader {
+  let shader = Shader::new(gl, type_);
+  shader.set_source(src.as_bytes());
+  let success = shader.compile();
+
+  let log = shader.get_info_log();
+  let log = String::from_utf8_lossy(&log);
+  if !success {
+    panic!("Shader compilation error(s):\n{}", log);
+  } else if !log.is_empty() {
+    eprintln!("Shader compilation warning(s):\n{}", log);
+  }
+
+  shader
+}
+
+pub fn link_program(gl: SharedContext, vertex: &Shader, fragment: &Shader) -> Program {
+  let program = Program::new(gl);
+  program.attach_shader(vertex);
+  program.attach_shader(fragment);
+  let success = program.link();
+
+  let log = program.get_info_log();
+  let log = String::from_utf8_lossy(&log);
+  if !success {
+    panic!("Program linking error(s):\n{}", log);
+  } else if !log.is_empty() {
+    eprintln!("Program linking warning(s):\n{}", log);
+  }
+
+  program.detach_shader(vertex);
+  program.detach_shader(fragment);
+  program.load_descriptors();
+  program
+}

crates/cardboard_oogl/examples/textures.rs

@@ -1,10 +1,11 @@
 use sdl2::event::{Event, WindowEvent};
 use sdl2::keyboard::Keycode;
-use sdl2::video::{GLProfile, Window};
 
 use cardboard_math::*;
 use cardboard_oogl::*;
-use std::rc::Rc;
+
+#[path = "common.rs"]
+mod common;
 
 #[repr(C, packed)]
 #[derive(Debug, Copy, Clone)]
@@ -39,45 +40,32 @@ static FS_SRC: &str = r#"#version 100
   precision highp float;
   varying vec4 v_color;
   varying vec2 v_texcoord;
+  uniform float u_blending_factor;
   uniform sampler2D u_tex1;
   uniform sampler2D u_tex2;
   void main() {
-    gl_FragColor = mix(texture2D(u_tex1, v_texcoord), texture2D(u_tex2, v_texcoord), 0.2) * v_color;
+    gl_FragColor = mix(
+      texture2D(u_tex1, v_texcoord), texture2D(u_tex2, v_texcoord), u_blending_factor
+    ) * v_color;
   }
 "#;
 
 const IMAGE_DATA_1: &[u8] = include_bytes!("./assets/LearnOpenGL/container.jpeg");
 const IMAGE_DATA_2: &[u8] = include_bytes!("./assets/LearnOpenGL/awesomeface.png");
 
 fn main() {
-  let sdl_context = sdl2::init().unwrap();
-  let video_subsystem = sdl_context.video().unwrap();
-
-  let gl_attr = video_subsystem.gl_attr();
-  gl_attr.set_context_profile(GLProfile::GLES);
-  gl_attr.set_context_version(2, 0);
-
-  let window = video_subsystem
-    .window("cardboard_oogl textures example", 800, 600)
-    .resizable()
-    .opengl()
-    .allow_highdpi()
-    .build()
-    .unwrap();
-
-  let sdl_gl_ctx = window.gl_create_context().unwrap();
-  let gl = Rc::new(Context::load_with(&video_subsystem, sdl_gl_ctx));
+  let (_sdl_context, _video_subsystem, window, mut event_pump, gl) =
+    common::prepare_example_gl_context("textures", vec2(800, 600));
 
-  let mut event_pump = sdl_context.event_pump().unwrap();
+  let vs = common::compile_shader(gl.share(), VS_SRC, ShaderType::Vertex);
+  let fs = common::compile_shader(gl.share(), FS_SRC, ShaderType::Fragment);
 
-  let vs = compile_shader(gl.share(), VS_SRC, ShaderType::Vertex);
-  let fs = compile_shader(gl.share(), FS_SRC, ShaderType::Fragment);
-
-  let mut program = link_program(gl.share(), &vs, &fs);
+  let mut program = common::link_program(gl.share(), &vs, &fs);
 
   let attr_pos = program.get_attrib::<Vec2f>("a_pos");
   let attr_color = program.get_attrib::<Colorf>("a_color");
   let attr_texcoord = program.get_attrib::<Vec2f>("a_texcoord");
+  let uni_blending_factor = program.get_uniform::<f32>("u_blending_factor");
   let uni_tex1 = program.get_uniform::<TextureUnit>("u_tex1");
   let uni_tex2 = program.get_uniform::<TextureUnit>("u_tex2");
 
@@ -101,6 +89,7 @@ fn main() {
   let texture_unit2 = TextureUnit::new(gl.share());
   uni_tex1.set(&bound_program, &texture_unit1);
   uni_tex2.set(&bound_program, &texture_unit2);
+  uni_blending_factor.set(&bound_program, &0.2);
 
   let mut texture1 = load_jpeg_texture_2d(gl.share(), IMAGE_DATA_1);
   {
@@ -120,12 +109,7 @@ fn main() {
 
   gl.set_clear_color(colorn(0.1, 1.0));
 
-  fn reset_viewport(gl: &Context, window: &Window) {
-    let (w, h) = window.drawable_size();
-    gl.set_viewport(vec2(0, 0), vec2(w as i32, h as i32));
-  }
-
-  reset_viewport(&gl, &window);
+  common::reset_gl_viewport(&gl, &window);
 
   'running: loop {
     for event in event_pump.poll_iter() {
@@ -135,7 +119,7 @@ fn main() {
         }
 
         Event::Window { win_event: WindowEvent::SizeChanged(..), .. } => {
-          reset_viewport(&gl, &window);
+          common::reset_gl_viewport(&gl, &window);
         }
 
         _ => {}
@@ -149,42 +133,6 @@ fn main() {
   }
 }
 
-fn compile_shader(gl: SharedContext, src: &str, type_: ShaderType) -> Shader {
-  let shader = Shader::new(gl, type_);
-  shader.set_source(src.as_bytes());
-  let success = shader.compile();
-
-  let log = shader.get_info_log();
-  let log = String::from_utf8_lossy(&log);
-  if !success {
-    panic!("Shader compilation error(s):\n{}", log);
-  } else if !log.is_empty() {
-    eprintln!("Shader compilation warning(s):\n{}", log);
-  }
-
-  shader
-}
-
-fn link_program(gl: SharedContext, vertex: &Shader, fragment: &Shader) -> Program {
-  let program = Program::new(gl);
-  program.attach_shader(vertex);
-  program.attach_shader(fragment);
-  let success = program.link();
-
-  let log = program.get_info_log();
-  let log = String::from_utf8_lossy(&log);
-  if !success {
-    panic!("Program linking error(s):\n{}", log);
-  } else if !log.is_empty() {
-    eprintln!("Program linking warning(s):\n{}", log);
-  }
-
-  program.detach_shader(vertex);
-  program.detach_shader(fragment);
-  program.load_descriptors();
-  program
-}
-
 fn load_png_texture_2d(gl: SharedContext, encoded_data: &[u8]) -> Texture2D {
   let decoder = png::Decoder::new(encoded_data);
   let (info, mut reader) = decoder.read_info().unwrap();

crates/cardboard_oogl/examples/triangle.rs

@@ -1,10 +1,10 @@
 use sdl2::event::{Event, WindowEvent};
 use sdl2::keyboard::Keycode;
 use sdl2::video::{GLProfile, Window};
+use std::rc::Rc;
 
 use cardboard_math::*;
 use cardboard_oogl::*;
-use std::rc::Rc;
 
 #[repr(C, packed)]
 #[derive(Debug, Copy, Clone)]