use PBO for timelapse data read

src/rtt.cpp

@@ -411,3 +411,114 @@ bool RTT::valid() const noexcept
 {
     return texID || rboID || fboID;
 }
+
+//////////////////////////////////////////////////////////////////////////
+
+PBO::PBO(PBO&& other) noexcept
+{
+    bound_slot = other.bound_slot;
+    buffer_id = other.buffer_id;
+    mapped_ptr = other.mapped_ptr;
+    width = other.width;
+    height = other.height;
+    other.bound_slot = 0;
+    other.buffer_id = 0;
+    other.mapped_ptr = nullptr;
+    other.width = 0;
+    other.height = 0;
+}
+
+PBO& PBO::operator=(PBO&& other) noexcept
+{
+    bound_slot = other.bound_slot;
+    buffer_id = other.buffer_id;
+    mapped_ptr = other.mapped_ptr;
+    width = other.width;
+    height = other.height;
+    other.bound_slot = 0;
+    other.buffer_id = 0;
+    other.mapped_ptr = nullptr;
+    other.width = 0;
+    other.height = 0;
+    return *this;
+}
+
+PBO::~PBO() noexcept
+{
+    destroy();
+}
+
+bool PBO::create() noexcept
+{
+    App::I->render_task([this] {
+        glGenBuffers(1, &buffer_id);
+    });
+    return true;
+}
+
+bool PBO::create(RTT& rtt) noexcept
+{
+    App::I->render_task([this, &rtt] {
+        width = rtt.getWidth();
+        height = rtt.getHeight();
+        rtt.bindFramebuffer();
+        glGenBuffers(1, &buffer_id);
+        glBindBuffer(GL_PIXEL_PACK_BUFFER, buffer_id);
+        glBufferData(GL_PIXEL_PACK_BUFFER, width * height * 4, 0, GL_STREAM_DRAW);
+        glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, 0);
+        glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
+        rtt.unbindFramebuffer();
+    });
+    return true;
+}
+
+void PBO::destroy() noexcept
+{
+    if (buffer_id)
+    {
+        App::I->render_task_async([id=buffer_id] {
+            glDeleteBuffers(1, &id);
+        });
+        buffer_id = 0;
+        bound_slot = 0;
+        width = 0;
+        height = 0;
+        mapped_ptr = nullptr;
+    }
+}
+
+/*
+void PBO::bind_read() noexcept
+{
+    App::I->render_task([this] {
+        glBindBuffer(GL_PIXEL_UNPACK_BUFFER, buffer_id);
+        bound_slot = GL_PIXEL_UNPACK_BUFFER;
+    });
+}
+
+void PBO::unbind() noexcept
+{
+    App::I->render_task([this] {
+        glBindBuffer(bound_slot, buffer_id);
+    });
+}
+*/
+
+glm::uint8_t* PBO::map() noexcept
+{
+    App::I->render_task([this] {
+        glBindBuffer(GL_PIXEL_PACK_BUFFER, buffer_id);
+        mapped_ptr = (GLubyte*)glMapBuffer(GL_PIXEL_PACK_BUFFER, GL_READ_ONLY);
+        glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
+    });
+    return mapped_ptr;
+}
+
+void PBO::unmap() noexcept
+{
+    App::I->render_task([this] {
+        glBindBuffer(GL_PIXEL_PACK_BUFFER, buffer_id);
+        glUnmapBuffer(GL_PIXEL_PACK_BUFFER);
+        glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
+    });
+}