hrm

beppe_online/src/lib.rs

@@ -24,4 +24,68 @@ pub fn init_webgl_context(canvas_id: &str) -> Result<WebGlRenderingContext, JsVa
 
 
 // https://blog.logrocket.com/implement-webassembly-webgl-viewer-using-rust/#setup-environment
-pub fn create_
+pub fn create_shader(
+    gl: &WebGlRenderingContext,
+    shader_type: u32,
+    source: &str,
+) -> Result<WebGlShader, JsValue> {
+    let shader = gl.create_shader(shader_type)
+        .ok_or_else(|| JsValue::from_str("Unable to create shader object"))?;
+
+    g..shader_source(&shader, source);
+    gl.compile_shader(&shader);
+
+    if gl.get_shader_parameter(&shader. WebGlRenderingContext::COMPILE_STATUS)
+        .as_bool().unwrap_or(false) {
+            Ok(shader)
+    } else {
+        Err(JsValue::from_str(&gl.get_shader_info_log(&shader).unwrap_or_else(|| "Unknown error creating shader".into()),
+        ))
+    }
+}
+
+
+pub fn setup_shaders(gl: &WebGlRenderingContext) -> Result<WebGlProgram, JsValue> {
+    let vertex_shader_source = "
+        attribute vec3 coordinates;
+        void main(void) {
+            gl_Position = vec4(coordinates, 1.0);
+        }
+        ";
+    let fragment_shader_source = "
+        precision mediump float;
+        uniform vec4 fragColor;
+        void main(void) {
+            gl_FragColor = fragColor;
+        }
+        ";
+    let vertex_shader = create_shader(
+        &gl,
+        WebGlRenderingContext::VERTEX_SHADER,
+        vertex_shader_source,
+    ).unwrap();
+    let fragment_shader = create_shader(
+        &gl,
+        WebGlRenderingContext::FRAGMENT_SHADER,
+        fragment_shader_source,
+    ).unwrap();
+
+    let shader_program = gl.create_program().unwrap();
+    gl.attach_shader(&shader_program, &vertex_shader);
+    gl.attach_shader(&shader_program, &fragment_shader);
+    gl.link_program(&shader_program);
+
+    if gl.get_program_parameter(&shader_program, WebGlRenderingContext::LINK_STATUS)
+        .as_bool()
+        .unwrap_or(false) {
+            g.use_program(Some(&shader_program));
+            Ok(shader_program);
+    } else {
+        return Err(JsValue::from_str(
+                &gl.get_program_info_log(&shader_program)
+                .unwrap_or_else(|| "Unknown error linking program".into()),
+        ));
+    }
+}
+
+