add png image loading and enable transparency

Cargo.toml

@@ -22,6 +22,7 @@ erased-serde = "0.3"
 type-uuid = "0.1"
 shaderc = "0.6"
 libloading = "0.5.2"
+png = "0.16.0"
 # rspirv = { git = "https://github.com/gfx-rs/rspirv.git", rev = "baa469eae2932271174593eb066894d7a7a38439" }
 spirv-reflect = "0.2.3"
 bevy_derive = { path = "bevy_derive" }

examples/texture.rs

@@ -12,7 +12,7 @@ fn setup(world: &mut World) {
 
     let texture_handle = {
         let mut texture_storage = world.resources.get_mut::<AssetStorage<Texture>>().unwrap();
-        let texture = Texture::load(TextureType::Data(asset::create_texels(256), 256, 256));
+        let texture = Texture::load(TextureType::Png(concat!(env!("CARGO_MANIFEST_DIR"), "/assets/temp_bevy_logo.png").to_string()));
         texture_storage.add(texture)
     };
 
@@ -29,7 +29,7 @@ fn setup(world: &mut World) {
         })
         // light
         .add_archetype(LightEntity {
-            translation: Translation::new(4.0, -4.0, 5.0),
+            translation: Translation::new(4.0, 4.0, 5.0),
             ..Default::default()
         })
         // camera

src/asset/texture.rs

@@ -1,7 +1,9 @@
 use crate::{render::render_graph::{TextureDimension, TextureDescriptor}, asset::Asset};
+use std::fs::File;
 
 pub enum TextureType {
     Data(Vec<u8>, usize, usize),
+    Png(String) // TODO: please rethink this
 }
 
 pub struct Texture {
@@ -14,6 +16,13 @@ impl Asset<TextureType> for Texture {
     fn load(descriptor: TextureType) -> Self {
         let (data, width, height) = match descriptor {
             TextureType::Data(data, width, height) => (data.clone(), width, height),
+            TextureType::Png(path) => {
+                let decoder = png::Decoder::new(File::open(&path).unwrap());
+                let (info, mut reader) = decoder.read_info().unwrap();
+                let mut buf = vec![0; info.buffer_size()];
+                reader.next_frame(&mut buf).unwrap();
+                (buf, info.width as usize, info.height as usize)
+            }
         };
 
         Texture { data, width, height }

src/render/render_graph/pipelines/forward/mod.rs

@@ -48,8 +48,16 @@ impl ForwardPipelineBuilder for RenderGraphBuilder {
             })
             .add_color_state(wgpu::ColorStateDescriptor {
                 format: wgpu::TextureFormat::Bgra8UnormSrgb,
-                color_blend: wgpu::BlendDescriptor::REPLACE,
+                color_blend: wgpu::BlendDescriptor {
-                alpha_blend: wgpu::BlendDescriptor::REPLACE,
+                    src_factor: wgpu::BlendFactor::SrcAlpha,
+                    dst_factor: wgpu::BlendFactor::OneMinusSrcAlpha,
+                    operation: wgpu::BlendOperation::Add,
+                },
+                alpha_blend: wgpu::BlendDescriptor {
+                    src_factor: wgpu::BlendFactor::One,
+                    dst_factor: wgpu::BlendFactor::One,
+                    operation: wgpu::BlendOperation::Add,
+                },
                 write_mask: wgpu::ColorWrite::ALL,
             })
             .add_vertex_buffer_descriptor(Vertex::get_vertex_buffer_descriptor())