osb/source/rendering/StarWorldCamera.hpp

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#pragma once
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#include "StarWorldGeometry.hpp"
#include "StarGameTypes.hpp"
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#include "StarInterpolation.hpp"
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namespace Star {
class WorldCamera {
public:
void setScreenSize(Vec2U screenSize);
Vec2U screenSize() const;
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void setTargetPixelRatio(float targetPixelRatio);
void setPixelRatio(float pixelRatio);
float pixelRatio() const;
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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;
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void update(float dt);
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private:
WorldGeometry m_worldGeometry;
Vec2U m_screenSize;
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float m_pixelRatio = 1.0f;
float m_targetPixelRatio = 1.0f;
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Vec2F m_worldCenter;
};
inline void WorldCamera::setScreenSize(Vec2U screenSize) {
m_screenSize = screenSize;
}
inline Vec2U WorldCamera::screenSize() const {
return m_screenSize;
}
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inline void WorldCamera::setTargetPixelRatio(float targetPixelRatio) {
m_targetPixelRatio = targetPixelRatio;
}
inline void WorldCamera::setPixelRatio(float pixelRatio) {
m_pixelRatio = m_targetPixelRatio = pixelRatio;
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}
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inline float WorldCamera::pixelRatio() const {
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return m_pixelRatio;
}
inline void WorldCamera::setWorldGeometry(WorldGeometry geometry) {
m_worldGeometry = std::move(geometry);
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}
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);
}
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inline void WorldCamera::update(float dt) {
m_pixelRatio = lerp(exp(-20.0f * dt), m_targetPixelRatio, m_pixelRatio);
}
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}