1 files changed, 42 insertions, 0 deletions
diff --git a/WebInterface/wasm/webhogg/src/canvas.rs b/WebInterface/wasm/webhogg/src/canvas.rs
new file mode 100644
index 0000000..a0ef7d1
--- /dev/null
+++ b/WebInterface/wasm/webhogg/src/canvas.rs
@@ -0,0 +1,42 @@
+use web_sys::WebGl2RenderingContext as WebGl2;
+use wasm_bindgen::JsCast;
+use crate::webhogg_exception::WebhoggException;
+use crate::page::Page;
+
+pub struct Canvas {
+    ctx: WebGl2,
+}
+
+impl Canvas {
+    pub fn from_existing(id: &str, page: &Page) -> Result<Self, WebhoggException> {
+        let canvas_element = page.get_element(id)
+            .ok_or(WebhoggException::DomError(
+                    "could not obtain canvas element (id=canvas)"
+                    .to_string()))?;
+        let canvas_element = canvas_element
+            .dyn_into::<web_sys::HtmlCanvasElement>()
+            .map_err(|_| WebhoggException::DomError(
+                    "id=canvas is not a canvas element".to_string()))?;
+        debug!("successfully obtained canvas element");
+        let ctx = canvas_element.get_context("webgl2")
+            .map_err(|_| WebhoggException::WebGlContextError(
+                    "obtained invalid webgl2 context js value".to_string()))?
+            .ok_or(WebhoggException::WebGlContextError(
+                    "could not obtaine webgl2 context".to_string()))?
+            .dyn_into::<WebGl2>()
+            .map_err(|_| WebhoggException::WebGlContextError(
+                    "obtained invalid webgl2 context js object".to_string()))?;
+        debug!("successfully obtained webgl2 context");
+        Ok(Self {
+            ctx,
+        })
+    }
+
+    pub fn gl<'a>(&'a self) -> &'a WebGl2 {
+        &self.ctx
+    }
+
+    pub fn gl_mut<'a>(&'a mut self) -> &'a mut WebGl2 {
+        &mut self.ctx
+    }
+}