Add texture support to the renderer

- Refactor to use the new model::Model struct
- Implement blinn-phong shading
- Add texture support for shaders

src/render.rs

@@ -1,7 +1,9 @@
 use crate::camera::Camera;
-use crate::ecs::{MeshHandle, Transform};
-use crate::model::Mesh;
+use crate::ecs::{ModelHandle, Transform};
+use crate::model::{Model};
+use glium::texture::{RawImage2d, SrgbTexture2d};
 use glium::{uniform, Program, Surface};
+use glium::uniforms::{MinifySamplerFilter, MagnifySamplerFilter, SamplerWrapFunction};
 use glam::Vec3;
 use hecs::World;
 use glium::glutin::surface::WindowSurface;
@@ -9,16 +11,25 @@ use glium::glutin::surface::WindowSurface;
 pub struct GliumRenderer {
     display: glium::Display<WindowSurface>,
     program: Program,
-    pub meshes: Vec<Mesh>,
+    white_tex: SrgbTexture2d,
+
+    pub models: Vec<Model>,
+
     params: glium::DrawParameters<'static>,
 }
 
 impl GliumRenderer {
     pub fn new(display: glium::Display<WindowSurface>) -> anyhow::Result<Self> {
-        const VERT: &str = include_str!("../resources/shaders/gl_solid_color.vert");
-        const FRAG: &str = include_str!("../resources/shaders/gl_solid_color.frag");
+        const VERT_SRC: &str = include_str!("../resources/shaders/gl_textured.vert");
+        const FRAG_SRC: &str = include_str!("../resources/shaders/gl_textured.frag");
 
-        let program = Program::from_source(&display, VERT, FRAG, None)?;
+        let program = Program::from_source(&display, VERT_SRC, FRAG_SRC, None)?;
+
+        let white_tex = {
+            let data = vec![255u8, 255u8, 255u8, 255u8];
+            let raw  = RawImage2d::from_raw_rgba(data, (1, 1));
+            SrgbTexture2d::new(&display, raw)?
+        };
 
         let params = glium::DrawParameters {
             depth: glium::Depth {
@@ -29,7 +40,13 @@ impl GliumRenderer {
             .. Default::default()
         };
         
-        Ok(Self { display, program, meshes: Vec::new(), params })
+        Ok(Self {
+            display,
+            program,
+            white_tex,
+            models: Vec::new(),
+            params,
+        })
     }
 
     fn draw_scene<S: Surface>(&self, world: &World, target: &mut S) {
@@ -41,20 +58,41 @@ impl GliumRenderer {
             }
         };
 
-        let light_dir: Vec3 = Vec3::new(-1.0, -1.0, -1.0).normalize();
+        // Direction from the light source (0,+Y) towards the scene.
+        let light_dir: Vec3 = Vec3::new(0.0, -1.0, 0.0).normalize();
+
+        for (_, (tr, mh)) in world.query::<(&Transform, &ModelHandle)>().iter() {
+            let model = &self.models[mh.0];
+            let mesh  = &model.mesh;
+            let mat   = &model.material;
+
+            let tex_ref: &SrgbTexture2d = mat.base_color.as_ref().unwrap_or(&self.white_tex);
+
+            let mut sampler = tex_ref.sampled();
+            sampler = sampler.wrap_function(SamplerWrapFunction::Repeat);
+            sampler = sampler.minify_filter(MinifySamplerFilter::Linear);
+            sampler = sampler.magnify_filter(MagnifySamplerFilter::Linear);
+
+            let c = mat.base_color_factor;
 
-        for (_, (tr, mh)) in world.query::<(&Transform, &MeshHandle)>().iter() {
-            let mesh = &self.meshes[mh.0];
             let uniforms = uniform! {
                 model:      tr.matrix().to_cols_array_2d(),
                 view:       cam.view().to_cols_array_2d(),
                 projection: cam.projection().to_cols_array_2d(),
-                light_dir:  [light_dir.x, light_dir.y, light_dir.z],
+                u_light:    [light_dir.x, light_dir.y, light_dir.z],
+                tex:        sampler,
+                color:      [c[0], c[1], c[2]],
+                uv_offset:  [mat.uv_offset.x, mat.uv_offset.y],
+                uv_scale:   [mat.uv_scale.x,  mat.uv_scale.y],
             };
 
-            target
-                .draw(&mesh.vbuf, &mesh.ibuf, &self.program, &uniforms, &self.params)
-                .unwrap();
+            target.draw(
+                &mesh.vbuf,
+                &mesh.ibuf,
+                &self.program,
+                &uniforms,
+                &self.params,
+            ).unwrap();
         }
     }