From: Mikko Rasa <tdb@tdb.fi>
Date: Sun, 19 Sep 2021 11:04:02 +0000 (+0300)
Subject: Query the attachments of the default framebuffer
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=d6122b75b00c0889a54536b5cea971d08184af8f;p=libs%2Fgl.git

Query the attachments of the default framebuffer

The exact pixel formats are unimportant for now and would be somewhat
convoluted to query.
---

diff --git a/source/core/framebuffer.cpp b/source/core/framebuffer.cpp
index 1dd2f61f..01a41074 100644
--- a/source/core/framebuffer.cpp
+++ b/source/core/framebuffer.cpp
@@ -34,6 +34,24 @@ Framebuffer::Framebuffer(unsigned i):
 	if(id)
 		throw invalid_argument("System framebuffer must have id 0");
 
+	if(EXT_framebuffer_object)
+	{
+		int value;
+		glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_BACK, GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE, &value);
+		if(value==GL_NONE)
+			glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_FRONT, GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE, &value);
+		if(value!=GL_NONE)
+			format = (format,COLOR_ATTACHMENT);
+
+		glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_DEPTH, GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE, &value);
+		if(value!=GL_NONE)
+			format = (format,DEPTH_ATTACHMENT);
+
+		glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_STENCIL, GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE, &value);
+		if(value!=GL_NONE)
+			format = (format,STENCIL_ATTACHMENT);
+	}
+
 	int view[4];
 	glGetIntegerv(GL_VIEWPORT, view);
 	width = view[2];
@@ -80,7 +98,7 @@ Framebuffer::~Framebuffer()
 
 void Framebuffer::set_format(const FrameFormat &fmt)
 {
-	if(!format.empty())
+	if(!format.empty() || !id)
 		throw invalid_operation("Framebuffer::set_format");
 	if(fmt.empty())
 		throw invalid_argument("Framebuffer::set_format");