Possible fix for T63685: macOS edit mode selection not working on second display

The idea is to force `glReadPixel` to run in the offscreen context.
And don't rely on any rendering context.

1 files changed, 13 insertions, 1 deletions

diff --git a/source/blender/draw/intern/draw_manager.c b/source/blender/draw/intern/draw_manager.c
index 7a95120b273..47d0e97d34b 100644
--- a/source/blender/draw/intern/draw_manager.c
+++ b/source/blender/draw/intern/draw_manager.c
@@ -2863,7 +2863,19 @@ void DRW_framebuffer_select_id_read(const rcti *rect, uint *r_buf)
 
   rcti rect_clamp = *rect;
   if (BLI_rcti_isect(&r, &rect_clamp, &rect_clamp)) {
-    GPU_texture_read_rect(g_select_buffer.texture_u32, GPU_DATA_UNSIGNED_INT, &rect_clamp, r_buf);
+    DRW_opengl_context_enable();
+    GPU_framebuffer_bind(g_select_buffer.framebuffer_select_id);
+    glReadBuffer(GL_COLOR_ATTACHMENT0);
+    glReadPixels(rect_clamp.xmin,
+                 rect_clamp.ymin,
+                 BLI_rcti_size_x(&rect_clamp),
+                 BLI_rcti_size_y(&rect_clamp),
+                 GL_RED_INTEGER,
+                 GL_UNSIGNED_INT,
+                 r_buf);
+
+    GPU_framebuffer_restore();
+    DRW_opengl_context_disable();
 
     if (!BLI_rcti_compare(rect, &rect_clamp)) {
       GPU_select_buffer_stride_realign(rect, &rect_clamp, r_buf);