From: Mikko Rasa <tdb@tdb.fi>
Date: Mon, 11 Oct 2021 12:25:52 +0000 (+0300)
Subject: Allow suppressing clear in a sequence by passing in a special tag
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=867c4e8c34fe24146f4f8cf6bd0b27a6d99aa1a2;p=libs%2Fgl.git

Allow suppressing clear in a sequence by passing in a special tag

Sequence doesn't pass on the tag it receives, so it can be used to
control the sequence's own behaviour instead.
---

diff --git a/source/render/sequence.cpp b/source/render/sequence.cpp
index e0fb408f..f7dea9bf 100644
--- a/source/render/sequence.cpp
+++ b/source/render/sequence.cpp
@@ -12,6 +12,8 @@ using namespace std;
 namespace Msp {
 namespace GL {
 
+Tag Sequence::noclear_tag = "noclear";
+
 Sequence::Sequence(unsigned w, unsigned h, const FrameFormat &f):
 	width(w),
 	height(h),
@@ -105,7 +107,7 @@ void Sequence::finish_frame()
 
 void Sequence::render(Renderer &renderer, Tag tag) const
 {
-	if(tag.id)
+	if(tag.id && tag!=noclear_tag)
 		return;
 
 	Renderer::Push _push(renderer);
@@ -115,7 +117,7 @@ void Sequence::render(Renderer &renderer, Tag tag) const
 	if(target[0])
 		renderer.set_framebuffer(&(target_ms ? target_ms : target[0])->get_framebuffer());
 
-	if(clear_enabled)
+	if(clear_enabled && tag!=noclear_tag)
 	{
 		const Framebuffer *target_fbo = renderer.get_framebuffer();
 		if(!target_fbo)
diff --git a/source/render/sequence.h b/source/render/sequence.h
index 9a3d0207..efead27f 100644
--- a/source/render/sequence.h
+++ b/source/render/sequence.h
@@ -79,6 +79,8 @@ private:
 	float clear_depth = 1.0f;
 	int clear_stencil = 0;
 
+	static Tag noclear_tag;
+
 public:
 	Sequence() = default;
 	Sequence(unsigned, unsigned, const FrameFormat &);