From d69ad62f0bb39b4ca32f668bf340764870ebbe81 Mon Sep 17 00:00:00 2001 From: Casey Mulcahy Date: Mon, 25 Aug 2025 13:01:16 -0400 Subject: [PATCH] Use OpenGL 3.1 on Windows 3.2+ causes high CPU usage on some (integrated?) graphics processors --- src/native/windows/wgl.rs | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/src/native/windows/wgl.rs b/src/native/windows/wgl.rs index 923f07777..a5c0818ff 100644 --- a/src/native/windows/wgl.rs +++ b/src/native/windows/wgl.rs @@ -406,13 +406,13 @@ impl Wgl { // CreateContextAttribsARB is supposed to create the context with // the highest version version possible - // but, somehow, sometimes, it creates 2.1 context when 3.2 is in fact available - // so this is a workaround: try to create 3.2, and if it fails, go for 2.1 + // but, somehow, sometimes, it creates 2.1 context when 3.1 is in fact available + // so this is a workaround: try to create 3.1, and if it fails, go for 2.1 let attrs = [ WGL_CONTEXT_MAJOR_VERSION_ARB, 3, WGL_CONTEXT_MINOR_VERSION_ARB, - 2, + 1, WGL_CONTEXT_FLAGS_ARB, WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB, WGL_CONTEXT_PROFILE_MASK_ARB, @@ -427,7 +427,7 @@ impl Wgl { ); if gl_ctx.is_null() { - eprintln!("WGL: failed to create 3.2 context, trying 2.1"); + eprintln!("WGL: failed to create 3.1 context, trying 2.1"); let attrs = [ WGL_CONTEXT_MAJOR_VERSION_ARB, @@ -445,10 +445,11 @@ impl Wgl { attrs.as_ptr() as *const _, ); } + if gl_ctx.is_null() { let err = GetLastError(); if err == (0xc0070000 | ERROR_INVALID_VERSION_ARB) { - panic!("WGL: Driver does not support OpenGL version 3.3"); + panic!("WGL: Driver does not support requested OpenGL version"); } else if err == (0xc0070000 | ERROR_INVALID_PROFILE_ARB) { panic!("WGL: Driver does not support the requested OpenGL profile"); } else if err == (0xc0070000 | ERROR_INCOMPATIBLE_DEVICE_CONTEXTS_ARB) {