qt: Refactor renderers buffer ownership

Invert the way buffers are created; make renderer create buffers for
renderer stack.
Use QImage bits as the buffer for software renderer.

src/qt/qt_softwarerenderer.cpp

@@ -1,20 +1,40 @@
 #include "qt_softwarerenderer.hpp"
 #include <QApplication>
+#include <QPainter>
 
-SoftwareRenderer::SoftwareRenderer(QWidget *parent) : QRasterWindow(parent->windowHandle()) { parentWidget = parent; }
+extern "C" {
+#include <86box/86box.h>
+#include <86box/video.h>
+}
 
-void SoftwareRenderer::paintEvent(QPaintEvent *event) {
-    (void) event;
+SoftwareRenderer::SoftwareRenderer(QWidget *parent)
+    : QRasterWindow(parent->windowHandle())
+{
+    parentWidget = parent;
+
+    images[0] = std::make_unique<QImage>(QSize(2048, 2048), QImage::Format_RGB32);
+    images[1] = std::make_unique<QImage>(QSize(2048, 2048), QImage::Format_RGB32);
+
+    buf_usage = std::vector<std::atomic_flag>(2);
+    buf_usage[0].clear();
+    buf_usage[1].clear();
+}
+
+void SoftwareRenderer::paintEvent(QPaintEvent* event) {
+    (void)event;
     onPaint(this);
 }
 
-void SoftwareRenderer::onBlit(const std::unique_ptr<uint8_t>* img, int x, int y, int w, int h, std::atomic_flag* in_use) {
+void SoftwareRenderer::onBlit(int buf_idx, int x, int y, int w, int h) {
+    /* TODO: should look into deleteLater() */
     auto tval = this;
     void* nuldata = 0;
     if (memcmp(&tval, &nuldata, sizeof(void*)) == 0) return;
-    memcpy(image.bits(), img->get(), 2048 * 2048 * 4);
-    in_use->clear();
-    source.setRect(x, y, w, h);
+
+    cur_image = buf_idx;
+    buf_usage[(buf_idx + 1) % 2].clear();
+    
+    source.setRect(x, y, w, h),
     update();
 }
 
@@ -29,3 +49,24 @@ bool SoftwareRenderer::event(QEvent *event)
     if (!eventDelegate(event, res)) return QRasterWindow::event(event);
     return res;
 }
+
+void SoftwareRenderer::onPaint(QPaintDevice* device) {
+    if (cur_image == -1)
+        return;
+
+    QPainter painter(device);
+    painter.setRenderHint(QPainter::SmoothPixmapTransform, video_filter_method > 0 ? true : false);
+    painter.fillRect(0, 0, device->width(), device->height(), QColorConstants::Black);
+    painter.setCompositionMode(QPainter::CompositionMode_Plus);
+    painter.drawImage(destination, *images[cur_image], source);
+}
+
+std::vector<std::tuple<uint8_t*, std::atomic_flag*>> SoftwareRenderer::getBuffers()
+{
+    std::vector<std::tuple<uint8_t*, std::atomic_flag*>> buffers;
+
+    buffers.push_back(std::make_tuple(images[0]->bits(), &buf_usage[0]));
+    buffers.push_back(std::make_tuple(images[1]->bits(), &buf_usage[1]));
+
+    return buffers;
+}