CameraHelpers.h

// Copyright eeGeo Ltd (2012-2014), All Rights Reserved

#pragma once

#include "Camera.h"
#include "Space.h"
#include "Geometry.h"
#include "VectorMathDecl.h"

namespace Eegeo
{
    namespace Camera
    {
        namespace CameraHelpers
        {
            void CalculateLookAt(
                const dv3& interestPointEcef,
                const v3& interestBasisFoward,
                float pitchRadians,
                float distanceCameraToInterest,
                dv3& out_cameraLocation,
                v3& out_cameraDirection,
                v3& out_cameraUp);
            
            void CalculateCameraOrientation(const v3& viewDirection, const v3& upAxis, m33& out_cameraOrientation);
            
            float GetAbsoluteBearingRadians(const dv3& pointEcef, const v3& headingDirection);
            
            void GetScreenPickRay(const RenderCamera& renderCamera, float screenPixelX, float screenPixelY, dv3& out_rayDirection);
            
            bool TryGetScreenPickIntersectionWithEarthCentredSphere(const RenderCamera& renderCamera, float screenPixelX, float screenPixelY, double sphereRadius, dv3& out_ecefIntersectionPoint);
            
            void EcefTangentBasisFromPointAndHeading(const dv3& pointEcef, float absoluteHeadingDegrees, Space::EcefTangentBasis& out_basis);
            
            v3 CameraRelativePoint(const dv3& pointEcef, const dv3& cameraOrigin);
            
            void GetAltitudeInterpolatedNearFar(float absoluteCameraAltitude, float approxTerrainAltitude, float approxTerrainAltitudeDelta, const double scalingFunctionAltitudeThreshold, float& out_nearDistance, float& out_farDistance);
            
            v3 GetScreenPositionFromLatLong(const Eegeo::Space::LatLong& latLong, const RenderCamera& renderCamera);
            
            v3 GetScreenPositionFromLatLongAlt(const Eegeo::Space::LatLongAltitude& latLongAlt, const RenderCamera& renderCamera);
            
            v3 GetScreenPositionFromEcef(const dv3& ecefPosition, const RenderCamera& renderCamera);

            Geometry::Ray ScreenPointToRay(const v2& screenPoint, const v2& screenDimensions, const m44& inverseViewProjectionMatrix, const dv3& viewOriginEcef);

            dv3 ScreenPointToRayDirection(const v2& screenPoint, const v2& screenDimensions, const m44& inverseViewProjectionMatrix);

            v3 ClipCoordToScreenPoint(const v4& clipCoord, const v2& screenDimensions);

            bool TryScreenProject(
                const dv3& pointEcef,
                const dv3& cameraOriginEcef,
                const m44& viewProjectionMatrix,
                const v2& screenDimensions,
                v3& out_screenPoint);

            v3 ScreenProjectWithDefaultHomogeneousW(
                const dv3& pointEcef,
                const dv3& cameraOriginEcef,
                const m44& viewProjectionMatrix,
                const v2& screenDimensions,
                const float defaultHomogeneousW = 0.1f);

            float VerticalFieldOfViewFromProjection(const m44& projectionMatrix);

            float NearClipDistanceFromProjection(const m44& projectionMatrix);

            float FarClipDistanceFromProjection(const m44& projectionMatrix);

            CameraState BuildCameraStateFromRenderCamera(const RenderCamera& camera, const dv3& cameraInterestPointEcef);
        }
    }
}