♻️ Allow models to render all their meshes in a batch

src/bin/pumpkin.rs

@@ -109,7 +109,6 @@ iota! {
 	        , MIN_ALBEDO
 	        , MIN_BRIGHT
 	        , TEXTURE
-	        , DITHER_PHASE
 }
 }
 
@@ -182,7 +181,6 @@ fn main () {
 			(MIN_ALBEDO, "min_albedo"),
 			(MIN_BRIGHT, "min_bright"),
 			(TEXTURE, "texture"),
-			(DITHER_PHASE, "dither_phase"),
 		].into_iter ()
 	});
 	
@@ -225,6 +223,18 @@ fn main () {
 	let mesh_sky = renderable_from_iqm_file ("sky-sphere.iqm");
 	let mesh_pitch = renderable_from_iqm_file ("pitch.iqm");
 	
+	let orange = color_from_255 ((210.0, 125.0, 44.0));
+	let green = color_from_255 ((52.0, 101.0, 36.0));
+	let white = color_from_255 ((255.0, 255.0, 255.0));
+	let _off_white = color_from_255 ((222.0, 238.0, 214.0));
+	let black = color_from_255 ((0.0, 0.0, 0.0));
+	let _off_black = color_from_255 ((20.0, 12.0, 28.0));
+	
+	let pumpkin_colors = vec! [
+		orange,
+		green,
+	];
+	
 	let (pitch_colors, grass_index) = {
 		let silver = (255.0, 255.0, 255.0);
 		let wood = (133.0, 76.0, 48.0);
@@ -297,7 +307,6 @@ fn main () {
 		}
 		
 		window.gl_make_current (&gl_ctx).unwrap ();
-		let dither_phase = rand::thread_rng ().gen_range (0, 16);
 		
 		let longitude = state.azimuth.to_radians ();
 		let latitude = (state.altitude - 90.0).to_radians ();
@@ -320,14 +329,6 @@ fn main () {
 		let sky_mvp_mat = view_mat * Mat4::from_scale ((16.0, 16.0, 16.0).into ());
 		
 		let light = Vec3::from ((2.0, 0.0, 5.0)).normalize ();
-		//let light = Vec3::from ((0.0, 0.0, 0.0)).normalize ();
-		
-		let orange = color_from_255 ((210.0, 125.0, 44.0));
-		let green = color_from_255 ((52.0, 101.0, 36.0));
-		let white = color_from_255 ((255.0, 255.0, 255.0));
-		let _off_white = color_from_255 ((222.0, 238.0, 214.0));
-		let black = color_from_255 ((0.0, 0.0, 0.0));
-		let _off_black = color_from_255 ((20.0, 12.0, 28.0));
 		
 		glezz::clear_color (1.0f32, 0.0f32, 1.0f32, 1.0f32);
 		glezz::clear (gl::COLOR_BUFFER_BIT | gl::DEPTH_BUFFER_BIT | gl::STENCIL_BUFFER_BIT);
@@ -362,24 +363,18 @@ fn main () {
 			glezz::uniform_3fv (unis [&OBJECT_SPACE_LIGHT], &object_space_light);
 			glezz::uniform_3fv (unis [&OBJECT_SPACE_SKY], &object_space_sky);
 			
-			{
+			mesh_pumpkin.draw_all (&attrs, |i| {
-				glezz::uniform_3fv (unis [&ALBEDO], &orange);
+				glezz::uniform_3fv (unis [&ALBEDO], &pumpkin_colors [i]);
-				mesh_pumpkin.draw (&attrs, 0);
+				true
-				
+			});
-				glezz::uniform_3fv (unis [&ALBEDO], &green);
-				mesh_pumpkin.draw (&attrs, 1);
-			}
 			
 			let mvp = view_mat * world_model_mat;
 			glezz::uniform_matrix_4fv (unis [&MVP], &mvp);
 			
-			for (i, color) in pitch_colors.iter ().enumerate ().take (mesh_pitch.num_meshes ())
+			mesh_pitch.draw_all (&attrs, |i| {
-			{
+				glezz::uniform_3fv (unis [&ALBEDO], &pitch_colors [i]);
-				glezz::uniform_3fv (unis [&ALBEDO], color);
+				i != grass_index
-				if i != grass_index {
+			});
-					mesh_pitch.draw (&attrs, i);
-				}
-			}
 			
 			let draw_sky = true;
 			if draw_sky {
@@ -390,7 +385,7 @@ fn main () {
 				glezz::uniform_3fv (unis [&MIN_ALBEDO], &black);
 				glezz::uniform_1i (unis [&TEXTURE], 0);
 				
-				mesh_sky.draw (&attrs, 0);
+				mesh_sky.draw_all (&attrs, |_| true);
 			}
 			
 			glezz::enable (gl::STENCIL_TEST);
@@ -409,19 +404,12 @@ fn main () {
 			let mvp = view_mat * pumpkin_model_mat;
 			glezz::uniform_matrix_4fv (shadow_unis [&MVP], &mvp);
 			
-			{
+			mesh_pumpkin.draw_all (&shadow_attrs, |_| true);
-				mesh_pumpkin.draw (&shadow_attrs, 0);
-				mesh_pumpkin.draw (&shadow_attrs, 1);
-			}
 			
 			let mvp = view_mat * world_model_mat;
 			glezz::uniform_matrix_4fv (shadow_unis [&MVP], &mvp);
 			
-			for i in 0..mesh_pitch.num_meshes () {
+			mesh_pitch.draw_all (&shadow_attrs, |i| i != grass_index);
-				if i != grass_index {
-					mesh_pitch.draw (&shadow_attrs, i);
-				}
-			}
 			
 			unsafe {
 				gl::ColorMask (255, 255, 255, 255);

src/renderable_model.rs

@@ -37,6 +37,8 @@ unsafe fn vertex_attrib_pointer (id: Option <u32>, num_coords: i32, float_offset
 	}
 }
 
+pub type AttrMap = HashMap <String, Option <u32>>;
+
 impl RenderableModel {
 	pub fn from_iqm (model: &iqm::Model) -> RenderableModel {
 		let pos_bytes = model.get_vertex_slice (iqm::types::POSITION);
@@ -87,10 +89,12 @@ impl RenderableModel {
 		}
 	}
 	
-	pub fn draw (&self, attrs: &HashMap <String, Option <u32>>, mesh_num: usize) 
+	pub fn draw_ranged <F> (&self, 
+		attrs: &AttrMap, callback: F, 
+		start: usize, end: usize
+	) 
+	where F: Fn (usize) -> bool
 	{
-		let mesh = &self.meshes [mesh_num];
-		
 		self.vertexes.bind ();
 		self.indexes.bind ();
 		
@@ -98,9 +102,30 @@ impl RenderableModel {
 			vertex_attrib_pointer (attrs ["pos"], 3, 0);
 			vertex_attrib_pointer (attrs ["uv"], 2, self.num_pos);
 			vertex_attrib_pointer (attrs ["normal"], 3, self.num_pos + self.num_uv);
-			
-			gl::DrawRangeElements (gl::TRIANGLES, 0, self.indexes.max (), mesh.num_triangles * 3, gl::UNSIGNED_INT, (mesh.first_triangle * 3 * 4) as *const u8 as *const c_void);
 		}
+		
+		for mesh_num in start..end {
+			if ! callback (mesh_num) {
+				continue;
+			}
+			
+			let mesh = &self.meshes [mesh_num];
+			
+			unsafe {
+				gl::DrawRangeElements (gl::TRIANGLES, 0, self.indexes.max (), mesh.num_triangles * 3, gl::UNSIGNED_INT, (mesh.first_triangle * 3 * 4) as *const u8 as *const c_void);
+			}
+		}
+	}
+	
+	pub fn draw_all <F> (&self, attrs: &AttrMap, callback: F)
+	where F: Fn (usize) -> bool
+	{
+		self.draw_ranged (attrs, callback, 0, self.meshes.len ());
+	}
+	
+	pub fn draw (&self, attrs: &AttrMap, mesh_num: usize) 
+	{
+		self.draw_ranged (attrs, |_| true, mesh_num, mesh_num + 1);
 	}
 	
 	pub fn num_meshes (&self) -> usize {