From dfecbdd4fb8494272fd6b6a86fbee6bdbcda9e8d Mon Sep 17 00:00:00 2001
From: _ <>
Date: Mon, 6 Jan 2020 01:57:34 +0000
Subject: [PATCH] Shader class... appears to work

---
 src/main.rs | 120 +++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 114 insertions(+), 6 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 30bf37d..b87ea9f 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,10 +1,116 @@
-use gl::types::*;
-
 use sdl2::event::Event;
 use sdl2::keyboard::Keycode;
 
+use std::convert::TryInto;
 use std::time::Duration;
 
+const VERT_SHADER_SRC: &str = 
+"
+#define lowp
+#define mediump
+#define highp
+#line 0
+uniform highp mat4 uni_model;
+uniform highp mat4 uni_viewproj;
+
+attribute highp vec4 attr_pos;
+attribute mediump vec2 attr_uv;
+attribute lowp vec3 attr_normal;
+
+varying lowp vec4 vary_color;
+varying mediump vec2 vary_uv;
+
+void main (void) {
+	vary_uv = attr_uv;
+	
+	lowp vec4 light_color = vec4 (1.0);
+	
+	vary_color = light_color;
+	
+	vec4 world_pos = uni_model * attr_pos;
+	
+	gl_Position = uni_viewproj * world_pos;
+}";
+
+const FRAG_SHADER_SRC: &str = 
+"
+#define lowp
+#define mediump
+#define highp
+#line 0
+uniform lowp sampler2D uni_texture;
+
+varying lowp vec4 vary_color;
+varying mediump vec2 vary_uv;
+
+void main (void) {
+	gl_FragColor = texture2D (uni_texture, vary_uv) * vary_color;
+	//gl_FragColor = vec4 (1.0, 0.0, 1.0, 1.0);
+}
+";
+
+pub struct ShaderObject {
+	id: u32,
+}
+
+impl ShaderObject {
+	pub fn id (&self) -> u32 {
+		self.id
+	}
+	
+	pub fn new (shader_type: u32, source: &str) -> Result <ShaderObject, String>
+	{
+		let id = unsafe {
+			gl::CreateShader (shader_type)
+		};
+		
+		let sources = [
+			source.as_ptr () as *const i8,
+		];
+		
+		let lengths = [
+			source.len ().try_into ().unwrap (),
+		];
+		
+		let success = unsafe {
+			gl::ShaderSource (id, sources.len ().try_into ().unwrap (), sources.as_ptr (), lengths.as_ptr ());
+			gl::CompileShader (id);
+			
+			let mut success = 0;
+			gl::GetShaderiv (id, gl::COMPILE_STATUS, &mut success);
+			success == 1
+		};
+		
+		if success {
+			Ok (ShaderObject {
+				id,
+			})
+		}
+		else {
+			let mut info_log = vec! [0u8; 4096];
+			let mut log_length = 0;
+			
+			unsafe {
+				gl::GetShaderInfoLog (id, (info_log.len () - 1).try_into ().unwrap (), &mut log_length, info_log.as_mut_ptr () as *mut i8);
+			}
+			
+			info_log.truncate (log_length.try_into ().unwrap ());
+			
+			let info = String::from_utf8 (info_log).unwrap ();
+			
+			Err (info)
+		}
+	}
+}
+
+impl Drop for ShaderObject {
+	fn drop (&mut self) {
+		unsafe {
+			gl::DeleteShader (self.id);
+		}
+	}
+}
+
 fn main () {
 	let sdl_context = sdl2::init ().unwrap ();
 	let video_subsystem = sdl_context.video ().unwrap ();
@@ -15,9 +121,6 @@ fn main () {
 		.build ()
 	.unwrap ();
 	
-	println! ("{:?}", &video_subsystem);
-	println! ("{}", video_subsystem.current_video_driver ());
-	
 	gl::load_with (|s| {
 		let result = video_subsystem.gl_get_proc_address (s) as *const _;
 		//println! ("{:?}", result);
@@ -29,9 +132,14 @@ fn main () {
 	
 	let gl_ctx = window.gl_create_context ().unwrap ();
 	
+	window.gl_make_current (&gl_ctx).unwrap ();
+	
+	let vert_shader = ShaderObject::new (gl::VERTEX_SHADER, VERT_SHADER_SRC).unwrap ();
+	let frag_shader = ShaderObject::new (gl::FRAGMENT_SHADER, FRAG_SHADER_SRC).unwrap ();
+	
 	let mut event_pump = sdl_context.event_pump ().unwrap ();
 	'running: loop {
-		let mouse = event_pump.mouse_state ();
+		let _mouse = event_pump.mouse_state ();
 		
 		for event in event_pump.poll_iter() {
 			match event {