1 files changed, 117 insertions, 0 deletions
diff --git a/source/rendering/StarWorldCamera.hpp b/source/rendering/StarWorldCamera.hpp
new file mode 100644
index 0000000..fe1dbeb
--- /dev/null
+++ b/source/rendering/StarWorldCamera.hpp
@@ -0,0 +1,117 @@
+#ifndef STAR_WORLD_CAMERA_HPP
+#define STAR_WORLD_CAMERA_HPP
+
+#include "StarWorldGeometry.hpp"
+#include "StarGameTypes.hpp"
+
+namespace Star {
+
+class WorldCamera {
+public:
+  void setScreenSize(Vec2U screenSize);
+  Vec2U screenSize() const;
+
+  void setPixelRatio(unsigned pixelRatio);
+  unsigned pixelRatio() const;
+
+  void setWorldGeometry(WorldGeometry geometry);
+  WorldGeometry worldGeometry() const;
+
+  // Set the camera center position (in world space) to as close to the given
+  // location as possible while keeping the screen within world bounds.
+  // Returns the actual camera position.
+  void setCenterWorldPosition(Vec2F const& position);
+  Vec2F centerWorldPosition() const;
+
+  // Transforms world coordinates into one set of screen coordinates.  Since
+  // the world is non-euclidean, one world coordinate can transform to
+  // potentially an infinite number of screen coordinates.  This will retrun
+  // the closest to the center of the screen.
+  Vec2F worldToScreen(Vec2F const& worldCoord) const;
+
+  // Assumes top left corner of screen is (0, 0) in screen coordinates.
+  Vec2F screenToWorld(Vec2F const& screen) const;
+
+  // Returns screen dimensions in world space.
+  RectF worldScreenRect() const;
+
+  // Returns tile dimensions of the tiles that overlap with the screen
+  RectI worldTileRect() const;
+
+  // Returns the position of the lower left corner of the lower left tile of
+  // worldTileRect, in screen coordinates.
+  Vec2F tileMinScreen() const;
+
+private:
+  WorldGeometry m_worldGeometry;
+  Vec2U m_screenSize;
+  unsigned m_pixelRatio = 1;
+  Vec2F m_worldCenter;
+};
+
+inline void WorldCamera::setScreenSize(Vec2U screenSize) {
+  m_screenSize = screenSize;
+}
+
+inline Vec2U WorldCamera::screenSize() const {
+  return m_screenSize;
+}
+
+inline void WorldCamera::setPixelRatio(unsigned pixelRatio) {
+  m_pixelRatio = pixelRatio;
+}
+
+inline unsigned WorldCamera::pixelRatio() const {
+  return m_pixelRatio;
+}
+
+inline void WorldCamera::setWorldGeometry(WorldGeometry geometry) {
+  m_worldGeometry = move(geometry);
+}
+
+inline WorldGeometry WorldCamera::worldGeometry() const {
+  return m_worldGeometry;
+}
+
+inline Vec2F WorldCamera::centerWorldPosition() const {
+  return Vec2F(m_worldCenter);
+}
+
+inline Vec2F WorldCamera::worldToScreen(Vec2F const& worldCoord) const {
+  Vec2F wrappedCoord = m_worldGeometry.nearestTo(Vec2F(m_worldCenter), worldCoord);
+  return Vec2F(
+      (wrappedCoord[0] - m_worldCenter[0]) * (TilePixels * m_pixelRatio) + m_screenSize[0] / 2.0,
+      (wrappedCoord[1] - m_worldCenter[1]) * (TilePixels * m_pixelRatio) + m_screenSize[1] / 2.0
+    );
+}
+
+inline Vec2F WorldCamera::screenToWorld(Vec2F const& screen) const {
+  return Vec2F(
+      (screen[0] - m_screenSize[0] / 2.0) / (TilePixels * m_pixelRatio) + m_worldCenter[0],
+      (screen[1] - m_screenSize[1] / 2.0) / (TilePixels * m_pixelRatio) + m_worldCenter[1]
+    );
+}
+
+inline RectF WorldCamera::worldScreenRect() const {
+  // screen dimensions in world space
+  float w = (float)m_screenSize[0] / (TilePixels * m_pixelRatio);
+  float h = (float)m_screenSize[1] / (TilePixels * m_pixelRatio);
+  return RectF::withSize(Vec2F(m_worldCenter[0] - w / 2, m_worldCenter[1] - h / 2), Vec2F(w, h));
+}
+
+inline RectI WorldCamera::worldTileRect() const {
+  RectF screen = worldScreenRect();
+  Vec2I min = Vec2I::floor(screen.min());
+  Vec2I size = Vec2I::ceil(Vec2F(m_screenSize) / (TilePixels * m_pixelRatio) + (screen.min() - Vec2F(min)));
+  return RectI::withSize(min, size);
+}
+
+inline Vec2F WorldCamera::tileMinScreen() const {
+  RectF screenRect = worldScreenRect();
+  RectI tileRect = worldTileRect();
+  return (Vec2F(tileRect.min()) - screenRect.min()) * (TilePixels * m_pixelRatio);
+}
+
+}
+
+#endif