From 53b0b87bb75a0f590aa2cce3469fe8d78e69610d Mon Sep 17 00:00:00 2001
From: RuiwenTang <tangruiwen1989@gmail.com>
Date: Wed, 13 Dec 2023 13:41:11 +0800
Subject: [PATCH] gl_engine: optimize framebuffer creation and save some
 runtime memory

since the framebuffer will draw back to parent RenderPass, it can be
reused in next compose rendering.

So instead of create framebuffer every time when beginCompose is called, we
trying to reuse the framebuffer created before in the same stack level
---
 src/renderer/gl_engine/tvgGlRenderer.cpp | 19 ++++++++++++-------
 src/renderer/gl_engine/tvgGlRenderer.h   |  3 +--
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/src/renderer/gl_engine/tvgGlRenderer.cpp b/src/renderer/gl_engine/tvgGlRenderer.cpp
index 375a33cc..0d0115bb 100644
--- a/src/renderer/gl_engine/tvgGlRenderer.cpp
+++ b/src/renderer/gl_engine/tvgGlRenderer.cpp
@@ -106,7 +106,6 @@ bool GlRenderer::sync()
     GL_CHECK(glDisable(GL_SCISSOR_TEST));
 
     mRenderPassStack.clear();
-    mPoolIndex = 0;
     mClearBuffer = false;
 
     delete task;
@@ -154,17 +153,19 @@ bool GlRenderer::beginComposite(Compositor* cmp, CompositeMethod method, uint8_t
     cmp->method = method;
     cmp->opacity = opacity;
 
-    if (mPoolIndex >= mComposePool.size()) {
-        mComposePool.emplace_back(make_unique<GlRenderTarget>(surface.w, surface.h));
-        mComposePool.back()->init(mTargetFboId);
+    uint32_t index = mRenderPassStack.size() - 1;
+
+    if (index >= mComposePool.count) {
+        mComposePool.push( new GlRenderTarget(surface.w, surface.h));
+        mComposePool[index]->init(mTargetFboId);
     }
-    mRenderPassStack.emplace_back(GlRenderPass(mComposePool[mPoolIndex++].get()));
+    mRenderPassStack.emplace_back(GlRenderPass(mComposePool[index]));
 
     return true;
 }
 
 
-bool GlRenderer::endComposite(TVG_UNUSED Compositor* cmp)
+bool GlRenderer::endComposite(Compositor* cmp)
 {
     if (mComposeStack.empty()) return false;
     if (mComposeStack.back().get() != cmp) return false;
@@ -441,12 +442,16 @@ GlRenderer* GlRenderer::gen()
     return new GlRenderer();
 }
 
-GlRenderer::GlRenderer() :mViewport() ,mGpuBuffer(new GlStageBuffer), mPrograms()
+GlRenderer::GlRenderer() :mViewport() ,mGpuBuffer(new GlStageBuffer), mPrograms(), mComposePool()
 {
 }
 
 GlRenderer::~GlRenderer()
 {
+    for (auto i = 0; i < mComposePool.count; i++) {
+        if (mComposePool[i]) delete mComposePool[i];
+    }
+
     --rendererCnt;
 
     if (rendererCnt == 0 && initEngineCnt == 0) _termEngine();
diff --git a/src/renderer/gl_engine/tvgGlRenderer.h b/src/renderer/gl_engine/tvgGlRenderer.h
index e974c44c..5ae0c2bc 100644
--- a/src/renderer/gl_engine/tvgGlRenderer.h
+++ b/src/renderer/gl_engine/tvgGlRenderer.h
@@ -98,8 +98,7 @@ private:
     unique_ptr<GlStageBuffer> mGpuBuffer;
     vector<std::unique_ptr<GlProgram>> mPrograms;
     unique_ptr<GlRenderTarget> mRootTarget = {};
-    vector<unique_ptr<GlRenderTarget>> mComposePool = {};
-    size_t mPoolIndex = 0;
+    Array<GlRenderTarget*> mComposePool = {};
     vector<GlRenderPass> mRenderPassStack = {};
     vector<unique_ptr<Compositor>> mComposeStack = {};