gl_engine: enable msaa resolve in GLRenderPass

* use GLRenderBuffer in color and stencil attachment, also use x4 sample
  count by default.
* add msaa resolve logical at the end of a ComposeTask, so the normal
  color texture can get the final rendering result.

src/renderer/gl_engine/tvgGlRenderPass.cpp

@@ -48,6 +48,22 @@ void GlRenderTarget::init(GLint resolveId)
 
     GL_CHECK(glBindFramebuffer(GL_FRAMEBUFFER, mFbo));
 
+    GL_CHECK(glGenRenderbuffers(1, &mColorBuffer));
+    GL_CHECK(glBindRenderbuffer(GL_RENDERBUFFER, mColorBuffer));
+    GL_CHECK(glRenderbufferStorageMultisample(GL_RENDERBUFFER, 4, GL_RGBA8, mWidth, mHeight));
+
+    GL_CHECK(glGenRenderbuffers(1, &mStencilBuffer));
+
+    GL_CHECK(glBindRenderbuffer(GL_RENDERBUFFER, mStencilBuffer));
+
+    GL_CHECK(glRenderbufferStorageMultisample(GL_RENDERBUFFER, 4, GL_STENCIL_INDEX8, mWidth, mHeight));
+
+    GL_CHECK(glBindRenderbuffer(GL_RENDERBUFFER, 0));
+
+    GL_CHECK(glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, mColorBuffer));
+    GL_CHECK(glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER, mStencilBuffer));
+
+    // resolve target
     GL_CHECK(glGenTextures(1, &mColorTex));
 
     GL_CHECK(glBindTexture(GL_TEXTURE_2D, mColorTex));
@@ -60,16 +76,9 @@ void GlRenderTarget::init(GLint resolveId)
 
     GL_CHECK(glBindTexture(GL_TEXTURE_2D, 0));
 
-    GL_CHECK(glGenRenderbuffers(1, &mStencilBuffer));
+    GL_CHECK(glGenFramebuffers(1, &mResolveFbo));
-
+    GL_CHECK(glBindFramebuffer(GL_FRAMEBUFFER, mResolveFbo));
-    GL_CHECK(glBindRenderbuffer(GL_RENDERBUFFER, mStencilBuffer));
-
-    GL_CHECK(glRenderbufferStorage(GL_RENDERBUFFER, GL_STENCIL_INDEX8, mWidth, mHeight));
-
-    GL_CHECK(glBindRenderbuffer(GL_RENDERBUFFER, 0));
-
     GL_CHECK(glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, mColorTex, 0));
-    GL_CHECK(glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER, mStencilBuffer));
 
     GL_CHECK(glBindFramebuffer(GL_FRAMEBUFFER, resolveId));
 }

src/renderer/gl_engine/tvgGlRenderPass.h

@@ -40,14 +40,20 @@ public:
     void init(GLint resolveId);
 
     GLuint getFboId() { return mFbo; }
+    GLuint getResolveFboId() { return mResolveFbo; }
     GLuint getColorTexture() { return mColorTex; }
 
+    uint32_t getWidth() const { return mWidth; }
+    uint32_t getHeight() const { return mHeight; }
+
 private:
     uint32_t mWidth = 0;
     uint32_t mHeight = 0;
     GLuint mFbo = 0;
-    GLuint mColorTex = 0;
+    GLuint mColorBuffer = 0;
     GLuint mStencilBuffer = 0;
+    GLuint mResolveFbo = 0;
+    GLuint mColorTex = 0;
 };
 
 class GlRenderPass
@@ -66,7 +72,7 @@ public:
 
     template <class T>
     T* endRenderPass(GlProgram* program, GLuint targetFbo) {
-        return new T(program, targetFbo, mFbo->getFboId(), std::move(mTasks));
+        return new T(program, targetFbo, mFbo, std::move(mTasks));
     }
 private:
     GlRenderTarget* mFbo;

src/renderer/gl_engine/tvgGlRenderTask.cpp

@@ -22,6 +22,7 @@
 
 #include "tvgGlRenderTask.h"
 #include "tvgGlProgram.h"
+#include "tvgGlRenderPass.h"
 
 /************************************************************************/
 /* External Class Implementation                                        */
@@ -131,8 +132,8 @@ void GlStencilCoverTask::run()
     GL_CHECK(glDisable(GL_STENCIL_TEST));
 }
 
-GlComposeTask::GlComposeTask(GlProgram* program, GLuint target, GLuint selfFbo, Array<GlRenderTask*>&& tasks)
+GlComposeTask::GlComposeTask(GlProgram* program, GLuint target, GlRenderTarget* fbo, Array<GlRenderTask*>&& tasks)
- :GlRenderTask(program) ,mTargetFbo(target), mSelfFbo(selfFbo), mTasks()
+ :GlRenderTask(program) ,mTargetFbo(target), mFbo(fbo), mTasks()
 {
     mTasks.push(tasks);
     tasks.clear();
@@ -165,10 +166,23 @@ void GlComposeTask::run()
 
     GLenum stencil_attachment = GL_STENCIL_ATTACHMENT;
     GL_CHECK(glInvalidateFramebuffer(GL_FRAMEBUFFER, 1, &stencil_attachment));
+
+    onResolve();
 }
 
-GlBlitTask::GlBlitTask(GlProgram* program, GLuint target, GLuint compose, Array<GlRenderTask*>&& tasks)
+GLuint GlComposeTask::getSelfFbo() { return mFbo->getFboId(); }
- : GlComposeTask(program, target, compose, std::move(tasks))
+
+GLuint GlComposeTask::getResolveFboId() { return mFbo->getResolveFboId(); }
+
+void GlComposeTask::onResolve() {
+    GL_CHECK(glBindFramebuffer(GL_READ_FRAMEBUFFER, getSelfFbo()));
+    GL_CHECK(glBindFramebuffer(GL_DRAW_FRAMEBUFFER, getResolveFboId()));
+
+    GL_CHECK(glBlitFramebuffer(0, 0, mFbo->getWidth(), mFbo->getHeight(), 0, 0, mFbo->getWidth(), mFbo->getHeight(), GL_COLOR_BUFFER_BIT, GL_NEAREST));
+}
+
+GlBlitTask::GlBlitTask(GlProgram* program, GLuint target, GlRenderTarget* fbo, Array<GlRenderTask*>&& tasks)
+ : GlComposeTask(program, target, fbo, std::move(tasks))
 {
 }
 
@@ -189,8 +203,8 @@ void GlBlitTask::run()
     GL_CHECK(glBlitFramebuffer(0, 0, mWidth, mHeight, 0, 0, mWidth, mHeight, GL_COLOR_BUFFER_BIT, GL_NEAREST));
 }
 
-GlDrawBlitTask::GlDrawBlitTask(GlProgram* program, GLuint target, GLuint compose, Array<GlRenderTask*>&& tasks)
+GlDrawBlitTask::GlDrawBlitTask(GlProgram* program, GLuint target, GlRenderTarget* fbo, Array<GlRenderTask*>&& tasks)
- : GlComposeTask(program, target, compose, std::move(tasks))
+ : GlComposeTask(program, target, fbo, std::move(tasks))
 {
 }
 

src/renderer/gl_engine/tvgGlRenderTask.h

@@ -110,10 +110,12 @@ private:
     GlRenderTask* mCoverTask;
 };
 
+class GlRenderTarget;
+
 class GlComposeTask : public GlRenderTask 
 {
 public:
-    GlComposeTask(GlProgram* program, GLuint target, GLuint selfFbo, Array<GlRenderTask*>&& tasks);
+    GlComposeTask(GlProgram* program, GLuint target, GlRenderTarget* fbo, Array<GlRenderTask*>&& tasks);
     ~GlComposeTask() override;
 
     void run() override;
@@ -123,24 +125,30 @@ public:
 protected:
     GLuint getTargetFbo() { return mTargetFbo; }
 
-    GLuint getSelfFbo() { return mSelfFbo; }
+    GLuint getSelfFbo();
 
+    GLuint getResolveFboId();
+
+    virtual void onResolve();
 private:
     GLuint mTargetFbo;
-    GLuint mSelfFbo;
+    GlRenderTarget* mFbo;
     Array<GlRenderTask*> mTasks;
 };
 
 class GlBlitTask : public GlComposeTask
 {
 public:
-    GlBlitTask(GlProgram*, GLuint target, GLuint compose, Array<GlRenderTask*>&& tasks);
+    GlBlitTask(GlProgram*, GLuint target, GlRenderTarget* fbo, Array<GlRenderTask*>&& tasks);
     ~GlBlitTask() override = default;
 
     void setSize(uint32_t width, uint32_t height);
 
     void run() override;
 
+protected:
+    void onResolve() override {}
+
 private:
     uint32_t mWidth = 0;
     uint32_t mHeight = 0;
@@ -149,7 +157,7 @@ private:
 class GlDrawBlitTask : public GlComposeTask
 {
 public:
-    GlDrawBlitTask(GlProgram*, GLuint target, GLuint compose, Array<GlRenderTask*>&& tasks);
+    GlDrawBlitTask(GlProgram*, GLuint target, GlRenderTarget* fbo, Array<GlRenderTask*>&& tasks);
     ~GlDrawBlitTask() override = default;
 
     void run() override;