more ergonomic uniform

src/opengl/wrapper/uniform.rs

@@ -1,6 +1,7 @@
 use anyhow::Result as AnyhowResult;
 use gl::types::*;
 use std::os::raw::c_char;
+use std::ffi::CString;
 
 /// A typesafe handle on uniform IDs with convenience methods.
 #[derive(Clone, Debug, Copy)]
@@ -9,11 +10,13 @@ pub struct Uniform {
 }
 
 impl Uniform {
-  pub fn lookup(opengl_program_id: GLuint, identifier: *const c_char) -> AnyhowResult<Self> {
-    let mut loc = -1;
+  pub fn lookup(identifier: &str, opengl_program_id: GLuint) -> AnyhowResult<Self> {
+    let id_cstr : CString = CString::new(identifier)?;
+    let id_cstr_ptr : *const c_char = id_cstr.as_ptr() as *const c_char;
 
+    let mut loc = -1;
     unsafe {
-      loc = gl::GetUniformLocation(opengl_program_id, identifier);
+      loc = gl::GetUniformLocation(opengl_program_id, id_cstr_ptr);
     }
 
     Ok(Self {

src/point_cloud/point_cloud_renderer.rs

@@ -201,10 +201,6 @@ impl PointCloudRenderer {
     let PROJECTION : CString = CString::new("projection").expect("string is correct");
     let PROJECTION_PTR : *const c_char = PROJECTION.as_ptr() as *const c_char;
 
-    /// Uniform variable name in OpenGL shader program
-    let MODEL_VIEW : CString = CString::new("modelView").expect("string is correct");
-    let MODEL_VIEW_PTR : *const c_char = MODEL_VIEW.as_ptr() as *const c_char;
-
     /// Uniform variable name in OpenGL shader program
     let ENABLE_SHADING : CString = CString::new("enableShading").expect("string is correct");
     let ENABLE_SHADING_PTR : *const c_char = ENABLE_SHADING.as_ptr() as *const c_char;
@@ -238,7 +234,7 @@ impl PointCloudRenderer {
       point_cloud_texture_indices.push(gl::GetUniformLocation(program_id, POINT_CLOUD_1_PTR));
     }
 
-    let model_transform = Uniform::lookup(program_id, MODEL_VIEW_PTR).unwrap();
+    let model_transform = Uniform::lookup("modelView", program_id).unwrap();
 
     let color_vertex_attribute_location = unsafe {
       let location = gl::GetAttribLocation(program_id, COLOR_LOCATION_PTR);