From a4905536b9cf8b497ae1afea36852c0110c43394 Mon Sep 17 00:00:00 2001
From: Nathan Adams <dinnerbone@dinnerbone.com>
Date: Mon, 4 May 2020 23:33:45 +0200
Subject: [PATCH] render: Add texture target for wgpu render backend

---
 render/wgpu/src/lib.rs    |  2 +-
 render/wgpu/src/target.rs | 80 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 81 insertions(+), 1 deletion(-)

diff --git a/render/wgpu/src/lib.rs b/render/wgpu/src/lib.rs
index e0b54b261..b3fd4471d 100644
--- a/render/wgpu/src/lib.rs
+++ b/render/wgpu/src/lib.rs
@@ -32,7 +32,7 @@ mod utils;
 
 mod pipelines;
 mod shapes;
-mod target;
+pub mod target;
 
 pub struct WgpuRenderBackend<T: RenderTarget> {
     device: wgpu::Device,
diff --git a/render/wgpu/src/target.rs b/render/wgpu/src/target.rs
index a00b78407..a4326e844 100644
--- a/render/wgpu/src/target.rs
+++ b/render/wgpu/src/target.rs
@@ -79,3 +79,83 @@ impl RenderTarget for SwapChainTarget {
         self.swap_chain.get_next_texture().map(SwapChainTargetFrame)
     }
 }
+
+#[derive(Debug)]
+pub struct TextureTarget {
+    size: wgpu::Extent3d,
+    texture: wgpu::Texture,
+    format: wgpu::TextureFormat,
+}
+
+#[derive(Debug)]
+pub struct TextureTargetFrame(wgpu::TextureView);
+
+impl RenderTargetFrame for TextureTargetFrame {
+    fn view(&self) -> &wgpu::TextureView {
+        &self.0
+    }
+}
+
+impl TextureTarget {
+    pub fn new(device: &wgpu::Device, size: (u32, u32)) -> Self {
+        let size = wgpu::Extent3d {
+            width: size.0,
+            height: size.1,
+            depth: 1,
+        };
+        let label = create_debug_label!("Render target texture");
+        let format = wgpu::TextureFormat::Bgra8Unorm;
+        let texture = device.create_texture(&wgpu::TextureDescriptor {
+            label: label.as_deref(),
+            size,
+            array_layer_count: 1,
+            mip_level_count: 1,
+            sample_count: 1,
+            dimension: wgpu::TextureDimension::D2,
+            format,
+            usage: wgpu::TextureUsage::OUTPUT_ATTACHMENT | wgpu::TextureUsage::COPY_SRC,
+        });
+        Self {
+            size,
+            texture,
+            format,
+        }
+    }
+}
+
+impl RenderTarget for TextureTarget {
+    type Frame = TextureTargetFrame;
+
+    fn resize(&mut self, device: &wgpu::Device, width: u32, height: u32) {
+        self.size.width = width;
+        self.size.height = height;
+
+        let label = create_debug_label!("Render target texture");
+        self.texture = device.create_texture(&wgpu::TextureDescriptor {
+            label: label.as_deref(),
+            size: self.size,
+            array_layer_count: 1,
+            mip_level_count: 1,
+            sample_count: 1,
+            dimension: wgpu::TextureDimension::D2,
+            format: self.format,
+            usage: wgpu::TextureUsage::OUTPUT_ATTACHMENT | wgpu::TextureUsage::COPY_SRC,
+        });
+    }
+
+    fn format(&self) -> wgpu::TextureFormat {
+        self.format
+    }
+
+    fn width(&self) -> u32 {
+        self.size.width
+    }
+
+    fn height(&self) -> u32 {
+        self.size.height
+    }
+
+    fn get_next_texture(&mut self) -> Result<Self::Frame, wgpu::TimeOut> {
+        Ok(TextureTargetFrame(self.texture.create_default_view()))
+    }
+}