wraitii
924c6ce34e
Following comments by @vladislavbelov. Differential Revision: https://code.wildfiregames.com/D3860 This was SVN commit r25278.
395 lines
12 KiB
C++
395 lines
12 KiB
C++
/* Copyright (C) 2021 Wildfire Games.
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* This file is part of 0 A.D.
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*
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* 0 A.D. is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* 0 A.D. is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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* CCamera holds a view and a projection matrix. It also has a frustum
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* which can be used to cull objects for rendering.
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*/
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#include "precompiled.h"
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#include "Camera.h"
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#include "graphics/HFTracer.h"
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#include "graphics/Terrain.h"
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#include "lib/ogl.h"
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#include "maths/MathUtil.h"
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#include "maths/Vector4D.h"
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#include "ps/Game.h"
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#include "ps/World.h"
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#include "renderer/Renderer.h"
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#include "renderer/WaterManager.h"
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CCamera::CCamera()
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{
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// Set viewport to something anything should handle, but should be initialised
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// to window size before use.
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m_ViewPort.m_X = 0;
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m_ViewPort.m_Y = 0;
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m_ViewPort.m_Width = 800;
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m_ViewPort.m_Height = 600;
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}
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CCamera::~CCamera() = default;
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void CCamera::SetProjection(const CMatrix3D& matrix)
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{
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m_ProjType = ProjectionType::CUSTOM;
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m_ProjMat = matrix;
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}
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void CCamera::SetProjectionFromCamera(const CCamera& camera)
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{
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m_ProjType = camera.m_ProjType;
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m_NearPlane = camera.m_NearPlane;
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m_FarPlane = camera.m_FarPlane;
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if (m_ProjType == ProjectionType::PERSPECTIVE)
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{
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m_FOV = camera.m_FOV;
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}
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else if (m_ProjType == ProjectionType::ORTHO)
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{
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m_OrthoScale = camera.m_OrthoScale;
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}
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m_ProjMat = camera.m_ProjMat;
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}
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void CCamera::SetOrthoProjection(float nearp, float farp, float scale)
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{
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m_ProjType = ProjectionType::ORTHO;
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m_NearPlane = nearp;
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m_FarPlane = farp;
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m_OrthoScale = scale;
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const float halfHeight = 0.5f * m_OrthoScale;
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const float halfWidth = halfHeight * GetAspectRatio();
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m_ProjMat.SetOrtho(-halfWidth, halfWidth, -halfHeight, halfHeight, m_NearPlane, m_FarPlane);
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}
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void CCamera::SetPerspectiveProjection(float nearp, float farp, float fov)
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{
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m_ProjType = ProjectionType::PERSPECTIVE;
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m_NearPlane = nearp;
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m_FarPlane = farp;
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m_FOV = fov;
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m_ProjMat.SetPerspective(m_FOV, GetAspectRatio(), m_NearPlane, m_FarPlane);
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}
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// Updates the frustum planes. Should be called
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// everytime the view or projection matrices are
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// altered.
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void CCamera::UpdateFrustum(const CBoundingBoxAligned& scissor)
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{
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CMatrix3D MatFinal;
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CMatrix3D MatView;
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m_Orientation.GetInverse(MatView);
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MatFinal = m_ProjMat * MatView;
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m_ViewFrustum.SetNumPlanes(6);
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// get the RIGHT plane
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m_ViewFrustum[0].m_Norm.X = scissor[1].X*MatFinal._41 - MatFinal._11;
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m_ViewFrustum[0].m_Norm.Y = scissor[1].X*MatFinal._42 - MatFinal._12;
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m_ViewFrustum[0].m_Norm.Z = scissor[1].X*MatFinal._43 - MatFinal._13;
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m_ViewFrustum[0].m_Dist = scissor[1].X*MatFinal._44 - MatFinal._14;
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// get the LEFT plane
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m_ViewFrustum[1].m_Norm.X = -scissor[0].X*MatFinal._41 + MatFinal._11;
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m_ViewFrustum[1].m_Norm.Y = -scissor[0].X*MatFinal._42 + MatFinal._12;
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m_ViewFrustum[1].m_Norm.Z = -scissor[0].X*MatFinal._43 + MatFinal._13;
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m_ViewFrustum[1].m_Dist = -scissor[0].X*MatFinal._44 + MatFinal._14;
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// get the BOTTOM plane
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m_ViewFrustum[2].m_Norm.X = -scissor[0].Y*MatFinal._41 + MatFinal._21;
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m_ViewFrustum[2].m_Norm.Y = -scissor[0].Y*MatFinal._42 + MatFinal._22;
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m_ViewFrustum[2].m_Norm.Z = -scissor[0].Y*MatFinal._43 + MatFinal._23;
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m_ViewFrustum[2].m_Dist = -scissor[0].Y*MatFinal._44 + MatFinal._24;
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// get the TOP plane
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m_ViewFrustum[3].m_Norm.X = scissor[1].Y*MatFinal._41 - MatFinal._21;
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m_ViewFrustum[3].m_Norm.Y = scissor[1].Y*MatFinal._42 - MatFinal._22;
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m_ViewFrustum[3].m_Norm.Z = scissor[1].Y*MatFinal._43 - MatFinal._23;
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m_ViewFrustum[3].m_Dist = scissor[1].Y*MatFinal._44 - MatFinal._24;
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// get the FAR plane
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m_ViewFrustum[4].m_Norm.X = scissor[1].Z*MatFinal._41 - MatFinal._31;
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m_ViewFrustum[4].m_Norm.Y = scissor[1].Z*MatFinal._42 - MatFinal._32;
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m_ViewFrustum[4].m_Norm.Z = scissor[1].Z*MatFinal._43 - MatFinal._33;
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m_ViewFrustum[4].m_Dist = scissor[1].Z*MatFinal._44 - MatFinal._34;
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// get the NEAR plane
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m_ViewFrustum[5].m_Norm.X = -scissor[0].Z*MatFinal._41 + MatFinal._31;
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m_ViewFrustum[5].m_Norm.Y = -scissor[0].Z*MatFinal._42 + MatFinal._32;
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m_ViewFrustum[5].m_Norm.Z = -scissor[0].Z*MatFinal._43 + MatFinal._33;
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m_ViewFrustum[5].m_Dist = -scissor[0].Z*MatFinal._44 + MatFinal._34;
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for (size_t i = 0; i < 6; ++i)
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m_ViewFrustum[i].Normalize();
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}
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void CCamera::ClipFrustum(const CPlane& clipPlane)
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{
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CPlane normClipPlane = clipPlane;
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normClipPlane.Normalize();
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m_ViewFrustum.AddPlane(normClipPlane);
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}
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void CCamera::SetViewPort(const SViewPort& viewport)
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{
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m_ViewPort.m_X = viewport.m_X;
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m_ViewPort.m_Y = viewport.m_Y;
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m_ViewPort.m_Width = viewport.m_Width;
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m_ViewPort.m_Height = viewport.m_Height;
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}
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float CCamera::GetAspectRatio() const
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{
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return static_cast<float>(m_ViewPort.m_Width) / static_cast<float>(m_ViewPort.m_Height);
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}
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void CCamera::GetViewQuad(float dist, Quad& quad) const
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{
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ENSURE(m_ProjType == ProjectionType::PERSPECTIVE || m_ProjType == ProjectionType::ORTHO);
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const float y = m_ProjType == ProjectionType::PERSPECTIVE ? dist * tanf(m_FOV * 0.5f) : m_OrthoScale * 0.5f;
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const float x = y * GetAspectRatio();
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quad[0].X = -x;
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quad[0].Y = -y;
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quad[0].Z = dist;
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quad[1].X = x;
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quad[1].Y = -y;
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quad[1].Z = dist;
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quad[2].X = x;
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quad[2].Y = y;
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quad[2].Z = dist;
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quad[3].X = -x;
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quad[3].Y = y;
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quad[3].Z = dist;
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}
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void CCamera::BuildCameraRay(int px, int py, CVector3D& origin, CVector3D& dir) const
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{
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ENSURE(m_ProjType == ProjectionType::PERSPECTIVE || m_ProjType == ProjectionType::ORTHO);
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// Coordinates relative to the camera plane.
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const float dx = static_cast<float>(px) / m_ViewPort.m_Width;
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const float dy = 1.0f - static_cast<float>(py) / m_ViewPort.m_Height;
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Quad points;
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GetViewQuad(m_FarPlane, points);
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// Transform from camera space to world space.
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for (CVector3D& point : points)
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point = m_Orientation.Transform(point);
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// Get world space position of mouse point at the far clipping plane.
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const CVector3D basisX = points[1] - points[0];
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const CVector3D basisY = points[3] - points[0];
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if (m_ProjType == ProjectionType::PERSPECTIVE)
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{
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// Build direction for the camera origin to the target point.
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origin = m_Orientation.GetTranslation();
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CVector3D targetPoint = points[0] + (basisX * dx) + (basisY * dy);
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dir = targetPoint - origin;
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}
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else if (m_ProjType == ProjectionType::ORTHO)
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{
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origin = m_Orientation.GetTranslation() + (basisX * (dx - 0.5f)) + (basisY * (dy - 0.5f));
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dir = m_Orientation.GetIn();
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}
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dir.Normalize();
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}
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void CCamera::GetScreenCoordinates(const CVector3D& world, float& x, float& y) const
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{
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CMatrix3D transform = m_ProjMat * m_Orientation.GetInverse();
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CVector4D screenspace = transform.Transform(CVector4D(world.X, world.Y, world.Z, 1.0f));
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x = screenspace.X / screenspace.W;
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y = screenspace.Y / screenspace.W;
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x = (x + 1) * 0.5f * m_ViewPort.m_Width;
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y = (1 - y) * 0.5f * m_ViewPort.m_Height;
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}
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CVector3D CCamera::GetWorldCoordinates(int px, int py, bool aboveWater) const
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{
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CHFTracer tracer(g_Game->GetWorld()->GetTerrain());
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int x, z;
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CVector3D origin, dir, delta, terrainPoint, waterPoint;
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BuildCameraRay(px, py, origin, dir);
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bool gotTerrain = tracer.RayIntersect(origin, dir, x, z, terrainPoint);
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if (!aboveWater)
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{
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if (gotTerrain)
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return terrainPoint;
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// Off the edge of the world?
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// Work out where it /would/ hit, if the map were extended out to infinity with average height.
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return GetWorldCoordinates(px, py, 50.0f);
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}
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CPlane plane;
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plane.Set(CVector3D(0.f, 1.f, 0.f), // upwards normal
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CVector3D(0.f, g_Renderer.GetWaterManager()->m_WaterHeight, 0.f)); // passes through water plane
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bool gotWater = plane.FindRayIntersection( origin, dir, &waterPoint );
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// Clamp the water intersection to within the map's bounds, so that
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// we'll always return a valid position on the map
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ssize_t mapSize = g_Game->GetWorld()->GetTerrain()->GetVerticesPerSide();
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if (gotWater)
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{
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waterPoint.X = Clamp<float>(waterPoint.X, 0.f, (mapSize - 1) * TERRAIN_TILE_SIZE);
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waterPoint.Z = Clamp<float>(waterPoint.Z, 0.f, (mapSize - 1) * TERRAIN_TILE_SIZE);
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}
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if (gotTerrain)
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{
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if (gotWater)
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{
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// Intersecting both heightmap and water plane; choose the closest of those
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if ((origin - terrainPoint).LengthSquared() < (origin - waterPoint).LengthSquared())
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return terrainPoint;
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else
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return waterPoint;
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}
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else
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{
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// Intersecting heightmap but parallel to water plane
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return terrainPoint;
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}
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}
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else
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{
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if (gotWater)
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{
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// Only intersecting water plane
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return waterPoint;
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}
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else
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{
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// Not intersecting terrain or water; just return 0,0,0.
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return CVector3D(0.f, 0.f, 0.f);
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}
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}
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}
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CVector3D CCamera::GetWorldCoordinates(int px, int py, float h) const
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{
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CPlane plane;
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plane.Set(CVector3D(0.f, 1.f, 0.f), CVector3D(0.f, h, 0.f)); // upwards normal, passes through h
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CVector3D origin, dir, delta, currentTarget;
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BuildCameraRay(px, py, origin, dir);
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if (plane.FindRayIntersection(origin, dir, ¤tTarget))
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return currentTarget;
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// No intersection with the infinite plane - nothing sensible can be returned,
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// so just choose an arbitrary point on the plane
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return CVector3D(0.f, h, 0.f);
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}
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CVector3D CCamera::GetFocus() const
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{
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// Basically the same as GetWorldCoordinates
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CHFTracer tracer(g_Game->GetWorld()->GetTerrain());
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int x, z;
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CVector3D origin, dir, delta, terrainPoint, waterPoint;
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origin = m_Orientation.GetTranslation();
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dir = m_Orientation.GetIn();
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bool gotTerrain = tracer.RayIntersect(origin, dir, x, z, terrainPoint);
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CPlane plane;
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plane.Set(CVector3D(0.f, 1.f, 0.f), // upwards normal
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CVector3D(0.f, g_Renderer.GetWaterManager()->m_WaterHeight, 0.f)); // passes through water plane
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bool gotWater = plane.FindRayIntersection( origin, dir, &waterPoint );
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// Clamp the water intersection to within the map's bounds, so that
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// we'll always return a valid position on the map
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ssize_t mapSize = g_Game->GetWorld()->GetTerrain()->GetVerticesPerSide();
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if (gotWater)
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{
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waterPoint.X = Clamp<float>(waterPoint.X, 0.f, (mapSize - 1) * TERRAIN_TILE_SIZE);
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waterPoint.Z = Clamp<float>(waterPoint.Z, 0.f, (mapSize - 1) * TERRAIN_TILE_SIZE);
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}
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if (gotTerrain)
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{
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if (gotWater)
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{
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// Intersecting both heightmap and water plane; choose the closest of those
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if ((origin - terrainPoint).LengthSquared() < (origin - waterPoint).LengthSquared())
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return terrainPoint;
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else
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return waterPoint;
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}
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else
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{
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// Intersecting heightmap but parallel to water plane
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return terrainPoint;
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}
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}
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else
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{
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if (gotWater)
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{
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// Only intersecting water plane
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return waterPoint;
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}
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else
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{
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// Not intersecting terrain or water; just return 0,0,0.
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return CVector3D(0.f, 0.f, 0.f);
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}
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}
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}
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void CCamera::LookAt(const CVector3D& camera, const CVector3D& focus, const CVector3D& up)
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{
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CVector3D delta = focus - camera;
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LookAlong(camera, delta, up);
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}
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void CCamera::LookAlong(const CVector3D& camera, CVector3D orientation, CVector3D up)
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{
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orientation.Normalize();
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up.Normalize();
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CVector3D s = orientation.Cross(up);
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m_Orientation._11 = -s.X; m_Orientation._12 = up.X; m_Orientation._13 = orientation.X; m_Orientation._14 = camera.X;
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m_Orientation._21 = -s.Y; m_Orientation._22 = up.Y; m_Orientation._23 = orientation.Y; m_Orientation._24 = camera.Y;
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m_Orientation._31 = -s.Z; m_Orientation._32 = up.Z; m_Orientation._33 = orientation.Z; m_Orientation._34 = camera.Z;
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m_Orientation._41 = 0.0f; m_Orientation._42 = 0.0f; m_Orientation._43 = 0.0f; m_Orientation._44 = 1.0f;
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}
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