egldisplay: Support creating a window with sRGB framebuffer

panda/src/egldisplay/eglGraphicsStateGuardian.cxx

@@ -223,6 +223,20 @@ choose_pixel_format(const FrameBufferProperties &properties,
     int err = eglGetError();
     if (_context && err == EGL_SUCCESS) {
       if (_visual) {
+        // This is set during window creation, but for now we have to pretend
+        // that we can honor the request, if we support the extension.
+        if (properties.get_srgb_color()) {
+          const char *extensions = eglQueryString(_egl_display, EGL_EXTENSIONS);
+          if (extensions != nullptr) {
+            vector_string tokens;
+            extract_words(extensions, tokens);
+
+            if (std::find(tokens.begin(), tokens.end(), "EGL_KHR_gl_colorspace") != tokens.end()) {
+              best_props.set_srgb_color(true);
+            }
+          }
+        }
+
         _fbprops = best_props;
         delete[] configs;
         return;

panda/src/egldisplay/eglGraphicsWindow.cxx

@@ -27,6 +27,14 @@
 #include "nativeWindowHandle.h"
 #include "get_x11.h"
 
+#ifndef EGL_GL_COLORSPACE_KHR
+#define EGL_GL_COLORSPACE_KHR 0x309D
+#endif
+
+#ifndef EGL_GL_COLORSPACE_SRGB_KHR
+#define EGL_GL_COLORSPACE_SRGB_KHR 0x3089
+#endif
+
 TypeHandle eglGraphicsWindow::_type_handle;
 
 /**
@@ -233,7 +241,16 @@ open_window() {
     return false;
   }
 
-  _egl_surface = eglCreateWindowSurface(_egl_display, eglgsg->_fbconfig, (NativeWindowType) _xwindow, nullptr);
+  EGLint attribs[4];
+  EGLint *attribs_p = nullptr;
+  if (eglgsg->get_fb_properties().get_srgb_color()) {
+    attribs[0] = EGL_GL_COLORSPACE_KHR;
+    attribs[1] = EGL_GL_COLORSPACE_SRGB_KHR;
+    attribs[2] = EGL_NONE;
+    attribs[3] = EGL_NONE;
+    attribs_p = attribs;
+  }
+  _egl_surface = eglCreateWindowSurface(_egl_display, eglgsg->_fbconfig, (NativeWindowType) _xwindow, attribs_p);
   if (eglGetError() != EGL_SUCCESS) {
     egldisplay_cat.error()
       << "Failed to create window surface.\n";