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#include "StarWorldCamera.hpp"
namespace Star {
void WorldCamera::setCenterWorldPosition(Vec2F const& position) {
// Only actually move the world center if a half pixel distance has been
// moved in any direction. This is sort of arbitrary, but helps prevent
// judder if the camera is at a boundary and floating point inaccuracy is
// causing the focus to jitter back and forth across the boundary.
if (fabs(position[0] - m_worldCenter[0]) < 1.0f / (TilePixels * m_pixelRatio * 2) && fabs(position[1] - m_worldCenter[1]) < 1.0f / (TilePixels * m_pixelRatio * 2))
return;
// First, make sure the camera center position is inside the main x
// coordinate bounds, and that the top and bototm of the screen are not
// outside of the y coordinate bounds.
m_worldCenter = m_worldGeometry.xwrap(position);
m_worldCenter[1] = clamp(m_worldCenter[1],
(float)m_screenSize[1] / (TilePixels * m_pixelRatio * 2),
m_worldGeometry.height() - (float)m_screenSize[1] / (TilePixels * m_pixelRatio * 2));
// Then, position the camera center position so that the tile grid is as
// close as possible aligned to whole pixel boundaries. This is incredibly
// important, because this means that even without any complicated rounding,
// elements drawn in world space that are aligned with TilePixels will
// eventually also be aligned to real screen pixels.
if (m_screenSize[0] % 2 == 0)
m_worldCenter[0] = round(m_worldCenter[0] * (TilePixels * m_pixelRatio)) / (TilePixels * m_pixelRatio);
else
m_worldCenter[0] = (round(m_worldCenter[0] * (TilePixels * m_pixelRatio) + 0.5f) - 0.5f) / (TilePixels * m_pixelRatio);
if (m_screenSize[1] % 2 == 0)
m_worldCenter[1] = round(m_worldCenter[1] * (TilePixels * m_pixelRatio)) / (TilePixels * m_pixelRatio);
else
m_worldCenter[1] = (round(m_worldCenter[1] * (TilePixels * m_pixelRatio) + 0.5f) - 0.5f) / (TilePixels * m_pixelRatio);
}
}
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