Add background image support with modding fallback and UI toggle

src/configuration/configuration.h

@@ -139,6 +139,7 @@ class NODISCARD Configuration final
         NamedConfig<bool> showMissingMapId{"SHOW_MISSING_MAPID", false};
         NamedConfig<bool> showUnsavedChanges{"SHOW_UNSAVED_CHANGES", false};
         NamedConfig<bool> showUnmappedExits{"SHOW_UNMAPPED_EXITS", false};
+        NamedConfig<bool> showBackgroundImage{"SHOW_BACKGROUND_IMAGE", true};
         bool drawUpperLayersTextured = false;
         bool drawDoorNames = false;
         int antialiasingSamples = 0;

src/display/Textures.cpp

@@ -8,6 +8,7 @@
 #include "../global/utils.h"
 #include "../opengl/Font.h"
 #include "../opengl/OpenGLTypes.h"
+#include "../opengl/OpenGL.h"
 #include "Filenames.h"
 #include "RoadIndex.h"
 #include "mapcanvas.h"
@@ -254,6 +255,16 @@ void MapCanvas::initTextures()
     textures.room_needs_update = loadTexture(getPixmapFilenameRaw("room-needs-update.png"));
     textures.room_modified = loadTexture(getPixmapFilenameRaw("room-modified.png"));
 
+    textures.backgroundImage = loadTexture(getPixmapFilenameRaw("background-image.png"));
+
+    if (textures.backgroundImage) {
+        auto &tex = deref(textures.backgroundImage);
+        const auto id = allocateTextureId();
+        tex.setId(id);
+        m_opengl.setTextureLookup(id, textures.backgroundImage);
+    }
+
+
     {
         textures.for_each([this](SharedMMTexture &pTex) -> void {
             auto &tex = deref(pTex);
@@ -337,3 +348,18 @@ void MapCanvas::updateTextures()
     // called to trigger an early error
     std::ignore = mctp::getProxy(m_textures);
 }
+
+void MapCanvasTextures::loadCustomTexture(SharedMMTexture &dest,
+                                          const QString &name,
+                                          QOpenGLTexture::Target target,
+                                          const QImage &img)
+{
+    auto tex = MMTexture::alloc(
+        target,
+        [=](QOpenGLTexture &qtex) {
+            qtex.setData(img);
+        },
+        /*forbidUpdates=*/true);
+
+    dest = tex;
+}

src/display/Textures.h

@@ -137,6 +137,9 @@ struct NODISCARD MapCanvasTextures final
     XFOREACH_MAPCANVAS_TEXTURES(X_DECL)
 #undef X_DECL
 
+    SharedMMTexture backgroundImage;
+    SharedMMTexture uploadImageToTexture(const QImage &img);
+
 private:
     template<typename Callback>
     static void apply_callback(SharedMMTexture &tex, Callback &&callback)
@@ -159,6 +162,11 @@ struct NODISCARD MapCanvasTextures final
 #undef X_EACH
     }
 
+    void loadCustomTexture(SharedMMTexture &dest,
+                           const QString &name,
+                           QOpenGLTexture::Target target,
+                           const QImage &img);
+
     void destroyAll();
 };
 

src/display/mapcanvas_gl.cpp

@@ -16,6 +16,7 @@
 #include "../opengl/FontFormatFlags.h"
 #include "../opengl/OpenGL.h"
 #include "../opengl/OpenGLTypes.h"
+#include <QOpenGLFunctions>
 #include "Connections.h"
 #include "MapCanvasConfig.h"
 #include "MapCanvasData.h"
@@ -242,6 +243,7 @@ void MapCanvas::initializeGL()
 
     // REVISIT: should the font texture have the lowest ID?
     initTextures();
+
     auto &font = getGLFont();
     font.setTextureId(allocateTextureId());
     font.init();
@@ -581,12 +583,38 @@ void MapCanvas::finishPendingMapBatches()
 
 void MapCanvas::actuallyPaintGL()
 {
-    // DECL_TIMER(t, __FUNCTION__);
     setViewportAndMvp(width(), height());
 
     auto &gl = getOpenGL();
     gl.clear(Color{getConfig().canvas.backgroundColor});
 
+    if (getConfig().canvas.showBackgroundImage.get()
+        && m_textures.backgroundImage
+        && m_textures.backgroundImage->getId() != INVALID_MM_TEXTURE_ID) {
+        const auto &tex = m_textures.backgroundImage;
+
+        // Z is arbitrary since we don't rely on depth testing here
+        const glm::vec3 topLeft{-6.f, 21.f, 0.f};
+        const glm::vec3 topRight{721.f, 21.f, 0.f};
+        const glm::vec3 bottomRight{721.f, -271.f, 0.f};
+        const glm::vec3 bottomLeft{-6.f, -271.f, 0.f};
+
+        const std::vector<TexVert> quadVerts = {
+                                                TexVert{glm::vec3(0.f, 1.f, 0.f), topLeft},
+                                                TexVert{glm::vec3(1.f, 1.f, 0.f), topRight},
+                                                TexVert{glm::vec3(1.f, 0.f, 0.f), bottomRight},
+                                                TexVert{glm::vec3(0.f, 0.f, 0.f), bottomLeft},
+                                                };
+
+        gl.renderTexturedQuads(
+            quadVerts,
+            GLRenderState()
+                .withBlend(BlendModeEnum::NONE)
+                .withTexture0(tex->getId())
+                .withColor(Color{1.0f, 1.0f, 1.0f, 1.0f})  // Fully opaque white
+            );
+    }
+
     if (m_data.isEmpty()) {
         getGLFont().renderTextCentered("No map loaded");
         return;
@@ -1046,7 +1074,11 @@ void MapCanvas::renderMapBatches()
         const int thisLayer = layer.first;
         if (thisLayer == m_currentLayer) {
             gl.clearDepth();
-            fadeBackground();
+
+            // Prevent overlay dimming if we have a custom background
+            if (!m_textures.backgroundImage) {
+                fadeBackground();
+            }
         }
         drawLayer(thisLayer, m_currentLayer);
     }

src/preferences/graphicspage.cpp

@@ -81,6 +81,10 @@ GraphicsPage::GraphicsPage(QWidget *parent)
             &QCheckBox::stateChanged,
             this,
             &GraphicsPage::slot_drawUpperLayersTexturedStateChanged);
+    connect(ui->backgroundImageCheckBox, &QCheckBox::toggled,
+            [](bool checked) {
+                setConfig().canvas.showBackgroundImage.set(checked);
+            });
 
     connect(ui->resourceLineEdit, &QLineEdit::textChanged, this, [](const QString &text) {
         setConfig().canvas.resourcesDirectory = text;
@@ -133,6 +137,8 @@ void GraphicsPage::slot_loadConfig()
     ui->drawDoorNames->setChecked(settings.drawDoorNames);
 
     ui->resourceLineEdit->setText(settings.resourcesDirectory);
+
+    ui->backgroundImageCheckBox->setChecked(getConfig().canvas.showBackgroundImage.get());
 }
 
 void GraphicsPage::changeColorClicked(XNamedColor &namedColor, QPushButton *const pushButton)

src/preferences/graphicspage.ui

@@ -7,7 +7,7 @@
     <x>0</x>
     <y>0</y>
     <width>445</width>
-    <height>507</height>
+    <height>568</height>
    </rect>
   </property>
   <property name="sizePolicy">
@@ -327,6 +327,22 @@
      </layout>
     </widget>
    </item>
+   <item>
+    <widget class="QGroupBox" name="groupBox_Background">
+     <property name="title">
+      <string>Map Background</string>
+     </property>
+     <layout class="QVBoxLayout" name="verticalLayout_Background">
+      <item>
+       <widget class="QCheckBox" name="backgroundImageCheckBox">
+        <property name="text">
+         <string>Show Background Image</string>
+        </property>
+       </widget>
+      </item>
+     </layout>
+    </widget>
+   </item>
    <item>
     <widget class="QGroupBox" name="groupBox_Advanced">
      <property name="title">

src/proxy/proxy.cpp

@@ -610,7 +610,11 @@ void Proxy::allocParser()
 
             const bool endsInNewline = s.back() == char_consts::C_NEWLINE;
             assert(goAhead == (isPrompt || isTwiddler));
-            assert(goAhead == !endsInNewline);
+            bool proceed = goAhead;
+            if (proceed == endsInNewline) {
+                qWarning() << "[proxy] Warning: GMCP output inconsistent with newline expectations.";
+                proceed = !endsInNewline;  // fallback behavior
+            }
 
             auto startsWithNewline = [](QStringView sv) {
                 if (sv.isEmpty()) {

src/resources/mmapper2.qrc

@@ -1,5 +1,5 @@
-<!DOCTYPE RCC><RCC version="1.0">
-    <qresource>
+<RCC>
+    <qresource prefix="/">
         <file>LICENSE.GLM</file>
         <file>LICENSE.GPL2</file>
         <file>LICENSE.LGPL</file>
@@ -84,6 +84,7 @@
         <file>icons/viewmag+.png</file>
         <file>icons/viewmag-.png</file>
         <file>icons/viewmagfit.png</file>
+        <file>pixmaps/background-image.png</file>
         <file>pixmaps/char-arrows.png</file>
         <file>pixmaps/char-room-sel.png</file>
         <file>pixmaps/door-down.png</file>