test rendering ui to texture

res/scripts/hud.lua

@@ -126,6 +126,8 @@ function on_hud_open()
     configure_SSAO()
 
     hud.default_hand_controller = update_hand
+
+    gui.root.root:add("<frame size='16' color='#FF0000'><label>Hello, World</label></frame>")
 end
 
 function on_hud_render()

src/graphics/core/Framebuffer.cpp

@@ -89,6 +89,10 @@ Texture* Framebuffer::getTexture() const {
     return texture.get();
 }
 
+std::shared_ptr<Texture> Framebuffer::getSharedTexture() const {
+    return texture;
+}
+
 uint Framebuffer::getWidth() const {
     return width;
 }

src/graphics/core/Framebuffer.hpp

@@ -13,7 +13,7 @@ class Framebuffer : public Bindable {
     uint width;
     uint height;
     uint format;
-    std::unique_ptr<Texture> texture;
+    std::shared_ptr<Texture> texture;
 public:
     Framebuffer(uint fbo, uint depth, std::unique_ptr<Texture> texture);
     Framebuffer(uint width, uint height, bool alpha=false);
@@ -33,6 +33,8 @@ public:
     /// @brief Get framebuffer color attachment
     Texture* getTexture() const;
 
+    std::shared_ptr<Texture> getSharedTexture() const;
+
     /// @brief Get framebuffer width
     uint getWidth() const;
     /// @brief Get framebuffer height

src/graphics/ui/elements/Frame.cpp

@@ -0,0 +1,42 @@
+#include "Frame.hpp"
+
+#include "assets/Assets.hpp"
+#include "graphics/core/Batch2D.hpp"
+#include "graphics/core/Framebuffer.hpp"
+#include "graphics/core/DrawContext.hpp"
+#include "graphics/core/Texture.hpp"
+#include "window/Window.hpp"
+#include "../GUI.hpp"
+
+using namespace gui;
+
+static inline constexpr int MAX_TEXTURE_SIZE = 2048;
+
+gui::Frame::Frame(GUI& gui) : Container(gui, {}), fbo(nullptr) {}
+
+gui::Frame::~Frame() = default;
+
+void gui::Frame::draw(const DrawContext& pctx, const Assets& assets) {
+    glm::ivec2 size = getSize();
+    if (size.x <= 0 || size.y <= 0 ||
+        size.x > MAX_TEXTURE_SIZE || size.y > MAX_TEXTURE_SIZE) {
+        return;
+    }
+    auto& nonConstASsets = const_cast<Assets&>(assets);
+    if (fbo && (fbo->getWidth() != size.x || fbo->getHeight() != size.y)) {
+        fbo->resize(size.x, size.y);
+        nonConstASsets.store(fbo->getSharedTexture(), texture);
+    } else if (fbo == nullptr) {
+        fbo = std::make_unique<Framebuffer>(size.x, size.y, true);
+        nonConstASsets.store(fbo->getSharedTexture(), texture);
+    }
+
+    // ui uses flipped camera with matrix based on main viewport
+    setPos({0, pctx.getViewport().y - size.y});
+    
+    auto ctx = pctx.sub();
+    ctx.setFramebuffer(fbo.get());
+    display::clear();
+    Container::draw(ctx, assets);
+    ctx.getBatch2D()->flush();
+}

src/graphics/ui/elements/Frame.hpp

@@ -0,0 +1,18 @@
+#pragma once
+
+#include "Container.hpp"
+
+class Framebuffer;
+
+namespace gui {
+    class Frame final : public Container {
+    public:
+        explicit Frame(GUI& gui);
+        virtual ~Frame();
+
+        void draw(const DrawContext& pctx, const Assets& assets) override;
+    private:
+        std::unique_ptr<Framebuffer> fbo;
+        std::string texture = "gui/no_icon";
+    };
+}

src/graphics/ui/gui_xml.cpp

@@ -8,6 +8,7 @@
 #include "elements/Button.hpp"
 #include "elements/Canvas.hpp"
 #include "elements/CheckBox.hpp"
+#include "elements/Frame.hpp"
 #include "elements/Image.hpp"
 #include "elements/InlineFrame.hpp"
 #include "elements/InputBindBox.hpp"
@@ -850,6 +851,15 @@ static std::shared_ptr<UINode> read_page_box(
     return menu;
 }
 
+static std::shared_ptr<UINode> read_frame(
+    UiXmlReader& reader, const xml::xmlelement& element
+) {
+    auto& gui = reader.getGUI();
+    auto frame = std::make_shared<Frame>(gui);
+    read_container_impl(reader, element, *frame, true);
+    return frame;
+}
+
 static std::shared_ptr<UINode> read_iframe(
     UiXmlReader& reader, const xml::xmlelement& element
 ) {
@@ -867,6 +877,7 @@ UiXmlReader::UiXmlReader(gui::GUI& gui, scriptenv&& env)
     contextStack.emplace("");
     add("image", read_image);
     add("canvas", read_canvas);
+    add("frame", read_frame);
     add("iframe", read_iframe);
     add("label", read_label);
     add("panel", read_panel);