Camera.h

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// Copyright © 2008-2021 Pioneer Developers. See AUTHORS.txt for details
// Licensed under the terms of the GPL v3. See licenses/GPL-3.txt
 
#ifndef _CAMERA_H
#define _CAMERA_H
 
#include "Color.h"
#include "FrameId.h"
#include "graphics/Frustum.h"
#include "graphics/Light.h"
#include "matrix4x4.h"
#include "vector3.h"
 
class Body;
class Frame;
 
namespace Graphics {
    class Material;
    class Renderer;
} // namespace Graphics
 
class CameraContext : public RefCounted {
public:
    // camera for rendering to width x height with view frustum properties
    CameraContext(float width, float height, float fovAng, float zNear, float zFar);
    ~CameraContext();
 
    float GetWidth() const { return m_width; }
    float GetHeight() const { return m_height; }
    float GetFovAng() const { return m_fovAng; }
    float GetZNear() const { return m_zNear; }
    float GetZFar() const { return m_zFar; }
 
    // frame to position the camera relative to
    void SetCameraFrame(FrameId frame) { m_frame = frame; }
    // return the parent frame of this camera
    FrameId GetCameraFrame() const { return m_frame; }
 
    // camera position relative to the frame origin
    void SetCameraPosition(const vector3d &pos) { m_pos = pos; }
 
    // camera orientation relative to the frame origin
    void SetCameraOrient(const matrix3x3d &orient) { m_orient = orient; }
 
    const vector3d GetCameraPos() const { return m_pos; }
    const matrix3x3d &GetCameraOrient() const { return m_orient; }
 
    // get the frustum. use for projection
    const Graphics::Frustum &GetFrustum() const { return m_frustum; }
 
    // generate and destroy the camere frame, used mostly to transform things to camera space
    void BeginFrame();
    void EndFrame();
 
    FrameId GetTempFrame() const { return m_camFrame; }
 
    // apply projection and modelview transforms to the renderer
    void ApplyDrawTransforms(Graphics::Renderer *r);
 
private:
    float m_width;
    float m_height;
    float m_fovAng;
    float m_zNear;
    float m_zFar;
 
    Graphics::Frustum m_frustum;
 
    FrameId m_frame;
    vector3d m_pos;
    matrix3x3d m_orient;
 
    FrameId m_camFrame;
};
 
class Camera {
public:
    Camera(RefCountedPtr<CameraContext> context, Graphics::Renderer *renderer);
 
    const CameraContext *GetContext() const { return m_context.Get(); }
 
    void Update();
    void Draw(const Body *excludeBody = nullptr);
 
    // camera-specific light with attached source body
    class LightSource {
    public:
        LightSource(const Body *b, Graphics::Light &light) :
            m_body(b),
            m_light(light) {}
 
        const Body *GetBody() const { return m_body; }
        const Graphics::Light &GetLight() const { return m_light; }
 
    private:
        const Body *m_body;
        Graphics::Light m_light;
    };
 
    struct Shadow {
        vector3d centre;
        float srad;
        float lrad;
 
        bool operator<(const Shadow &other) const { return srad / lrad < other.srad / other.lrad; }
    };
 
    void CalcShadows(const int lightNum, const Body *b, std::vector<Shadow> &shadowsOut) const;
    float ShadowedIntensity(const int lightNum, const Body *b) const;
    void PrincipalShadows(const Body *b, const int n, std::vector<Shadow> &shadowsOut) const;
 
    // lights with properties in camera space
    const std::vector<LightSource> &GetLightSources() const { return m_lightSources; }
    int GetNumLightSources() const { return static_cast<Uint32>(m_lightSources.size()); }
 
private:
    RefCountedPtr<CameraContext> m_context;
    Graphics::Renderer *m_renderer;
 
    std::unique_ptr<Graphics::Material> m_billboardMaterial;
 
    // temp attrs for sorting and drawing
    struct BodyAttrs {
        Body *body;
 
        // camera position and orientation relative to the body
        vector3d viewCoords;
        matrix4x4d viewTransform;
 
        // body distance from camera
        double camDist;
 
        // body flags. DRAW_LAST is the interesting one
        Uint32 bodyFlags;
 
        // if true, draw object as billboard of billboardSize at billboardPos
        bool billboard;
        vector3f billboardPos;
        float billboardSize;
        Color billboardColor;
 
        // for sorting. "should a be drawn before b?"
        // NOTE: Add below function (thus an indirection) in order
        // to decouple Camera from Body.h
        static bool sort_BodyAttrs(const BodyAttrs &a, const BodyAttrs &b);
        friend bool operator<(const BodyAttrs &a, const BodyAttrs &b)
        {
            return sort_BodyAttrs(a, b);
        };
    };
 
    std::list<BodyAttrs> m_sortedBodies;
    std::vector<LightSource> m_lightSources;
};
 
#endif