1 files changed, 122 insertions, 0 deletions
diff --git a/src/samples/firebirds/plugin/CollisionDetector.cpp b/src/samples/firebirds/plugin/CollisionDetector.cpp
new file mode 100644
index 0000000..1eca5c9
--- /dev/null
+++ b/src/samples/firebirds/plugin/CollisionDetector.cpp
@@ -0,0 +1,122 @@
+#include "CollisionDetector.h"
+
+#include "../../../base/ScopeTimer.h"
+#include "../../../wrapper/WrapHelper.h"
+
+namespace avg {
+
+CollisionDetector::CollisionDetector(const Bitmap& bmpA, const Bitmap& bmpB)
+{
+    m_pBmpA = new Bitmap(bmpA.getSize(), B8G8R8A8);
+    m_pBmpA->copyPixels(bmpA);
+    m_pBmpB = new Bitmap(bmpB.getSize(), B8G8R8A8);
+    m_pBmpB->copyPixels(bmpB);
+}
+
+CollisionDetector::~CollisionDetector()
+{
+    delete m_pBmpA;
+    delete m_pBmpB;
+}
+
+static ProfilingZoneID CollisionDetectorProfilingZone("Detect collisions");
+
+bool CollisionDetector::detect(glm::vec2 posA, glm::vec2 posB)
+{
+    ScopeTimer Timer(CollisionDetectorProfilingZone);
+
+    int widthA = m_pBmpA->getSize().x;
+    int heightA = m_pBmpA->getSize().y;
+    int rightA = posA.x + widthA;
+    int bottomA = posA.y + heightA;
+    int widthB = m_pBmpB->getSize().x;
+    int heightB = m_pBmpB->getSize().y;
+    int rightB = posB.x + widthB;
+    int bottomB = posB.y + heightB;
+
+    // bounding box test
+    if (rightA <= posB.x || posA.x >= rightB || bottomA <= posB.y || posA.y >= bottomB) {
+        return false;
+    }
+
+    // pixel level test
+
+    // calculate x overlap
+    int dX = posB.x - posA.x;
+    if (dX < 0) {
+        posA.x = 0;
+        posB.x = -dX;
+    }
+    else {
+        posA.x = dX;
+        posB.x = 0;
+    }
+    int width;
+    dX = rightB - rightA;
+    if (dX < 0)
+        width = std::min(widthA + dX, widthB);
+    else
+        width = std::min(widthB - dX, widthA);
+    // calculate y overlap
+    int dY = posB.y - posA.y;
+    if (dY < 0) {
+        posA.y = 0;
+        posB.y = -dY;
+    }
+    else {
+        posA.y = dY;
+        posB.y = 0;
+    }
+    int height;
+    dY = bottomB - bottomA;
+    if (dY < 0)
+        height = std::min(heightA + dY, heightB);
+    else
+        height = std::min(heightB - dY, heightA);
+
+    // test alpha channels
+    const unsigned char* pPixStartA = m_pBmpA->getPixels() +
+            (int) posA.y * m_pBmpA->getStride() +
+            (int) posA.x * 4 + 3; // alpha channel of 1st A pixel
+    const unsigned char* pPixStartB = m_pBmpB->getPixels() +
+            (int) posB.y * m_pBmpB->getStride() +
+            (int) posB.x * 4 + 3; // alpha channel of 1st B pixel
+    const unsigned char* pPixA = pPixStartA;
+    const unsigned char* pPixB = pPixStartB;
+    for (int y = 0; y < height; y++) {
+        for (int x = 0; x < width; x++) {
+            if (*pPixA && *pPixB) {
+                return true; // both pixels have alpha > 0 --> collision
+            }
+            pPixA += 4;
+            pPixB += 4;
+        }
+        pPixA = pPixStartA + y * m_pBmpA->getStride();
+        pPixB = pPixStartB + y * m_pBmpB->getStride();
+    }
+
+    return false;
+}
+
+} // namespace avg
+
+
+using namespace boost::python;
+
+BOOST_PYTHON_MODULE(collisiondetector)
+{
+    class_<avg::CollisionDetector, boost::noncopyable>("CollisionDetector", no_init)
+        .def(init<avg::Bitmap&, avg::Bitmap&>())
+        .def("detect", &avg::CollisionDetector::detect)
+        ;
+}
+
+
+AVG_PLUGIN_API void registerPlugin()
+{
+    initcollisiondetector(); // created by BOOST_PYTHON_MODULE
+    object mainModule(handle<>(borrowed(PyImport_AddModule("__main__"))));
+    object collisiondetectorModule(handle<>(PyImport_ImportModule("collisiondetector")));
+    mainModule.attr("collisiondetector") = collisiondetectorModule;
+}
+