/* Copyright (C) 2023 Wildfire Games.
* This file is part of 0 A.D.
*
* 0 A.D. is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* 0 A.D. is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with 0 A.D. If not, see .
*/
#include "precompiled.h"
#include "Camera.h"
#include "graphics/HFTracer.h"
#include "graphics/Terrain.h"
#include "maths/MathUtil.h"
#include "maths/Vector2D.h"
#include "maths/Vector4D.h"
#include "ps/Game.h"
#include "ps/World.h"
#include "renderer/Renderer.h"
#include "renderer/SceneRenderer.h"
#include "renderer/WaterManager.h"
CCamera::CCamera()
{
// Set viewport to something anything should handle, but should be initialised
// to window size before use.
m_ViewPort.m_X = 0;
m_ViewPort.m_Y = 0;
m_ViewPort.m_Width = 800;
m_ViewPort.m_Height = 600;
}
CCamera::~CCamera() = default;
void CCamera::SetProjection(const CMatrix3D& matrix)
{
m_ProjType = ProjectionType::CUSTOM;
m_ProjMat = matrix;
}
void CCamera::SetProjectionFromCamera(const CCamera& camera)
{
m_ProjType = camera.m_ProjType;
m_NearPlane = camera.m_NearPlane;
m_FarPlane = camera.m_FarPlane;
if (m_ProjType == ProjectionType::PERSPECTIVE)
{
m_FOV = camera.m_FOV;
}
else if (m_ProjType == ProjectionType::ORTHO)
{
m_OrthoScale = camera.m_OrthoScale;
}
m_ProjMat = camera.m_ProjMat;
}
void CCamera::SetOrthoProjection(float nearp, float farp, float scale)
{
m_ProjType = ProjectionType::ORTHO;
m_NearPlane = nearp;
m_FarPlane = farp;
m_OrthoScale = scale;
const float halfHeight = 0.5f * m_OrthoScale;
const float halfWidth = halfHeight * GetAspectRatio();
m_ProjMat.SetOrtho(-halfWidth, halfWidth, -halfHeight, halfHeight, m_NearPlane, m_FarPlane);
}
void CCamera::SetPerspectiveProjection(float nearp, float farp, float fov)
{
m_ProjType = ProjectionType::PERSPECTIVE;
m_NearPlane = nearp;
m_FarPlane = farp;
m_FOV = fov;
m_ProjMat.SetPerspective(m_FOV, GetAspectRatio(), m_NearPlane, m_FarPlane);
}
// Updates the frustum planes. Should be called
// everytime the view or projection matrices are
// altered.
void CCamera::UpdateFrustum(const CBoundingBoxAligned& scissor)
{
CMatrix3D MatFinal;
CMatrix3D MatView;
m_Orientation.GetInverse(MatView);
MatFinal = m_ProjMat * MatView;
m_ViewFrustum.SetNumPlanes(6);
// get the RIGHT plane
m_ViewFrustum[0].m_Norm.X = scissor[1].X*MatFinal._41 - MatFinal._11;
m_ViewFrustum[0].m_Norm.Y = scissor[1].X*MatFinal._42 - MatFinal._12;
m_ViewFrustum[0].m_Norm.Z = scissor[1].X*MatFinal._43 - MatFinal._13;
m_ViewFrustum[0].m_Dist = scissor[1].X*MatFinal._44 - MatFinal._14;
// get the LEFT plane
m_ViewFrustum[1].m_Norm.X = -scissor[0].X*MatFinal._41 + MatFinal._11;
m_ViewFrustum[1].m_Norm.Y = -scissor[0].X*MatFinal._42 + MatFinal._12;
m_ViewFrustum[1].m_Norm.Z = -scissor[0].X*MatFinal._43 + MatFinal._13;
m_ViewFrustum[1].m_Dist = -scissor[0].X*MatFinal._44 + MatFinal._14;
// get the BOTTOM plane
m_ViewFrustum[2].m_Norm.X = -scissor[0].Y*MatFinal._41 + MatFinal._21;
m_ViewFrustum[2].m_Norm.Y = -scissor[0].Y*MatFinal._42 + MatFinal._22;
m_ViewFrustum[2].m_Norm.Z = -scissor[0].Y*MatFinal._43 + MatFinal._23;
m_ViewFrustum[2].m_Dist = -scissor[0].Y*MatFinal._44 + MatFinal._24;
// get the TOP plane
m_ViewFrustum[3].m_Norm.X = scissor[1].Y*MatFinal._41 - MatFinal._21;
m_ViewFrustum[3].m_Norm.Y = scissor[1].Y*MatFinal._42 - MatFinal._22;
m_ViewFrustum[3].m_Norm.Z = scissor[1].Y*MatFinal._43 - MatFinal._23;
m_ViewFrustum[3].m_Dist = scissor[1].Y*MatFinal._44 - MatFinal._24;
// get the FAR plane
m_ViewFrustum[4].m_Norm.X = scissor[1].Z*MatFinal._41 - MatFinal._31;
m_ViewFrustum[4].m_Norm.Y = scissor[1].Z*MatFinal._42 - MatFinal._32;
m_ViewFrustum[4].m_Norm.Z = scissor[1].Z*MatFinal._43 - MatFinal._33;
m_ViewFrustum[4].m_Dist = scissor[1].Z*MatFinal._44 - MatFinal._34;
// get the NEAR plane
m_ViewFrustum[5].m_Norm.X = -scissor[0].Z*MatFinal._41 + MatFinal._31;
m_ViewFrustum[5].m_Norm.Y = -scissor[0].Z*MatFinal._42 + MatFinal._32;
m_ViewFrustum[5].m_Norm.Z = -scissor[0].Z*MatFinal._43 + MatFinal._33;
m_ViewFrustum[5].m_Dist = -scissor[0].Z*MatFinal._44 + MatFinal._34;
for (size_t i = 0; i < 6; ++i)
m_ViewFrustum[i].Normalize();
}
void CCamera::ClipFrustum(const CPlane& clipPlane)
{
CPlane normClipPlane = clipPlane;
normClipPlane.Normalize();
m_ViewFrustum.AddPlane(normClipPlane);
}
void CCamera::SetViewPort(const SViewPort& viewport)
{
m_ViewPort.m_X = viewport.m_X;
m_ViewPort.m_Y = viewport.m_Y;
m_ViewPort.m_Width = viewport.m_Width;
m_ViewPort.m_Height = viewport.m_Height;
}
float CCamera::GetAspectRatio() const
{
return static_cast(m_ViewPort.m_Width) / static_cast(m_ViewPort.m_Height);
}
void CCamera::GetViewQuad(float dist, Quad& quad) const
{
if (m_ProjType == ProjectionType::CUSTOM)
{
const CMatrix3D invProjection = m_ProjMat.GetInverse();
const std::array ndcCorners = {
CVector2D{-1.0f, -1.0f}, CVector2D{1.0f, -1.0f},
CVector2D{1.0f, 1.0f}, CVector2D{-1.0f, 1.0f}};
for (size_t idx = 0; idx < 4; ++idx)
{
const CVector2D& corner = ndcCorners[idx];
CVector4D nearCorner =
invProjection.Transform(CVector4D(corner.X, corner.Y, -1.0f, 1.0f));
nearCorner /= nearCorner.W;
CVector4D farCorner =
invProjection.Transform(CVector4D(corner.X, corner.Y, 1.0f, 1.0f));
farCorner /= farCorner.W;
const float t = (dist - nearCorner.Z) / (farCorner.Z - nearCorner.Z);
const CVector4D quadCorner = nearCorner * (1.0 - t) + farCorner * t;
quad[idx].X = quadCorner.X;
quad[idx].Y = quadCorner.Y;
quad[idx].Z = quadCorner.Z;
}
return;
}
const float y = m_ProjType == ProjectionType::PERSPECTIVE ? dist * tanf(m_FOV * 0.5f) : m_OrthoScale * 0.5f;
const float x = y * GetAspectRatio();
quad[0].X = -x;
quad[0].Y = -y;
quad[0].Z = dist;
quad[1].X = x;
quad[1].Y = -y;
quad[1].Z = dist;
quad[2].X = x;
quad[2].Y = y;
quad[2].Z = dist;
quad[3].X = -x;
quad[3].Y = y;
quad[3].Z = dist;
}
void CCamera::BuildCameraRay(int px, int py, CVector3D& origin, CVector3D& dir) const
{
ENSURE(m_ProjType == ProjectionType::PERSPECTIVE || m_ProjType == ProjectionType::ORTHO);
// Coordinates relative to the camera plane.
const float dx = static_cast(px) / m_ViewPort.m_Width;
const float dy = 1.0f - static_cast(py) / m_ViewPort.m_Height;
Quad points;
GetViewQuad(m_FarPlane, points);
// Transform from camera space to world space.
for (CVector3D& point : points)
point = m_Orientation.Transform(point);
// Get world space position of mouse point at the far clipping plane.
const CVector3D basisX = points[1] - points[0];
const CVector3D basisY = points[3] - points[0];
if (m_ProjType == ProjectionType::PERSPECTIVE)
{
// Build direction for the camera origin to the target point.
origin = m_Orientation.GetTranslation();
CVector3D targetPoint = points[0] + (basisX * dx) + (basisY * dy);
dir = targetPoint - origin;
}
else if (m_ProjType == ProjectionType::ORTHO)
{
origin = m_Orientation.GetTranslation() + (basisX * (dx - 0.5f)) + (basisY * (dy - 0.5f));
dir = m_Orientation.GetIn();
}
dir.Normalize();
}
void CCamera::GetScreenCoordinates(const CVector3D& world, float& x, float& y) const
{
CMatrix3D transform = m_ProjMat * m_Orientation.GetInverse();
CVector4D screenspace = transform.Transform(CVector4D(world.X, world.Y, world.Z, 1.0f));
x = screenspace.X / screenspace.W;
y = screenspace.Y / screenspace.W;
x = (x + 1) * 0.5f * m_ViewPort.m_Width;
y = (1 - y) * 0.5f * m_ViewPort.m_Height;
}
CVector3D CCamera::GetWorldCoordinates(int px, int py, bool aboveWater) const
{
CHFTracer tracer(g_Game->GetWorld()->GetTerrain());
int x, z;
CVector3D origin, dir, delta, terrainPoint, waterPoint;
BuildCameraRay(px, py, origin, dir);
bool gotTerrain = tracer.RayIntersect(origin, dir, x, z, terrainPoint);
if (!aboveWater)
{
if (gotTerrain)
return terrainPoint;
// Off the edge of the world?
// Work out where it /would/ hit, if the map were extended out to infinity with average height.
return GetWorldCoordinates(px, py, 50.0f);
}
CPlane plane;
plane.Set(CVector3D(0.f, 1.f, 0.f), // upwards normal
CVector3D(0.f, g_Renderer.GetSceneRenderer().GetWaterManager().m_WaterHeight, 0.f)); // passes through water plane
bool gotWater = plane.FindRayIntersection( origin, dir, &waterPoint );
// Clamp the water intersection to within the map's bounds, so that
// we'll always return a valid position on the map
const ssize_t mapSize = g_Game->GetWorld()->GetTerrain().GetVerticesPerSide();
if (gotWater)
{
waterPoint.X = Clamp(waterPoint.X, 0.f, (mapSize - 1) * TERRAIN_TILE_SIZE);
waterPoint.Z = Clamp(waterPoint.Z, 0.f, (mapSize - 1) * TERRAIN_TILE_SIZE);
}
if (gotTerrain)
{
if (gotWater)
{
// Intersecting both heightmap and water plane; choose the closest of those
if ((origin - terrainPoint).LengthSquared() < (origin - waterPoint).LengthSquared())
return terrainPoint;
else
return waterPoint;
}
else
{
// Intersecting heightmap but parallel to water plane
return terrainPoint;
}
}
else
{
if (gotWater)
{
// Only intersecting water plane
return waterPoint;
}
else
{
// Not intersecting terrain or water; just return 0,0,0.
return CVector3D(0.f, 0.f, 0.f);
}
}
}
CVector3D CCamera::GetWorldCoordinates(int px, int py, float h) const
{
CPlane plane;
plane.Set(CVector3D(0.f, 1.f, 0.f), CVector3D(0.f, h, 0.f)); // upwards normal, passes through h
CVector3D origin, dir, delta, currentTarget;
BuildCameraRay(px, py, origin, dir);
if (plane.FindRayIntersection(origin, dir, ¤tTarget))
return currentTarget;
// No intersection with the infinite plane - nothing sensible can be returned,
// so just choose an arbitrary point on the plane
return CVector3D(0.f, h, 0.f);
}
CVector3D CCamera::GetFocus() const
{
// Basically the same as GetWorldCoordinates
CHFTracer tracer(g_Game->GetWorld()->GetTerrain());
int x, z;
CVector3D origin, dir, delta, terrainPoint, waterPoint;
origin = m_Orientation.GetTranslation();
dir = m_Orientation.GetIn();
bool gotTerrain = tracer.RayIntersect(origin, dir, x, z, terrainPoint);
CPlane plane;
plane.Set(CVector3D(0.f, 1.f, 0.f), // upwards normal
CVector3D(0.f, g_Renderer.GetSceneRenderer().GetWaterManager().m_WaterHeight, 0.f)); // passes through water plane
bool gotWater = plane.FindRayIntersection( origin, dir, &waterPoint );
// Clamp the water intersection to within the map's bounds, so that
// we'll always return a valid position on the map
const ssize_t mapSize = g_Game->GetWorld()->GetTerrain().GetVerticesPerSide();
if (gotWater)
{
waterPoint.X = Clamp(waterPoint.X, 0.f, (mapSize - 1) * TERRAIN_TILE_SIZE);
waterPoint.Z = Clamp(waterPoint.Z, 0.f, (mapSize - 1) * TERRAIN_TILE_SIZE);
}
if (gotTerrain)
{
if (gotWater)
{
// Intersecting both heightmap and water plane; choose the closest of those
if ((origin - terrainPoint).LengthSquared() < (origin - waterPoint).LengthSquared())
return terrainPoint;
else
return waterPoint;
}
else
{
// Intersecting heightmap but parallel to water plane
return terrainPoint;
}
}
else
{
if (gotWater)
{
// Only intersecting water plane
return waterPoint;
}
else
{
// Not intersecting terrain or water; just return 0,0,0.
return CVector3D(0.f, 0.f, 0.f);
}
}
}
CBoundingBoxAligned CCamera::GetBoundsInViewPort(const CBoundingBoxAligned& boundigBox) const
{
const CVector3D cameraPosition = GetOrientation().GetTranslation();
if (boundigBox.IsPointInside(cameraPosition))
return CBoundingBoxAligned(CVector3D(-1.0f, -1.0f, 0.0f), CVector3D(1.0f, 1.0f, 0.0f));
const CMatrix3D viewProjection = GetViewProjection();
CBoundingBoxAligned viewPortBounds;
#define ADD_VISIBLE_POINT_TO_VIEWBOUNDS(POSITION) STMT( \
CVector4D v = viewProjection.Transform(CVector4D((POSITION).X, (POSITION).Y, (POSITION).Z, 1.0f)); \
if (v.W != 0.0f) \
viewPortBounds += CVector3D(v.X, v.Y, v.Z) * (1.0f / v.W); )
std::array worldPositions;
std::array isBehindNearPlane;
const CVector3D lookDirection = GetOrientation().GetIn();
// Check corners.
for (size_t idx = 0; idx < 8; ++idx)
{
worldPositions[idx] = CVector3D(boundigBox[(idx >> 0) & 0x1].X, boundigBox[(idx >> 1) & 0x1].Y, boundigBox[(idx >> 2) & 0x1].Z);
isBehindNearPlane[idx] = lookDirection.Dot(worldPositions[idx]) < lookDirection.Dot(cameraPosition) + GetNearPlane();
if (!isBehindNearPlane[idx])
ADD_VISIBLE_POINT_TO_VIEWBOUNDS(worldPositions[idx]);
}
// Check edges for intersections with the near plane.
for (size_t idxBegin = 0; idxBegin < 8; ++idxBegin)
for (size_t nextComponent = 0; nextComponent < 3; ++nextComponent)
{
const size_t idxEnd = idxBegin | (1u << nextComponent);
if (idxBegin == idxEnd || isBehindNearPlane[idxBegin] == isBehindNearPlane[idxEnd])
continue;
CVector3D intersection;
// Intersect the segment with the near plane.
if (!m_ViewFrustum[5].FindLineSegIntersection(worldPositions[idxBegin], worldPositions[idxEnd], &intersection))
continue;
ADD_VISIBLE_POINT_TO_VIEWBOUNDS(intersection);
}
#undef ADD_VISIBLE_POINT_TO_VIEWBOUNDS
if (viewPortBounds[0].X >= 1.0f || viewPortBounds[1].X <= -1.0f || viewPortBounds[0].Y >= 1.0f || viewPortBounds[1].Y <= -1.0f)
return CBoundingBoxAligned{};
return viewPortBounds;
}
void CCamera::LookAt(const CVector3D& camera, const CVector3D& focus, const CVector3D& up)
{
CVector3D delta = focus - camera;
LookAlong(camera, delta, up);
}
void CCamera::LookAlong(const CVector3D& camera, CVector3D orientation, CVector3D up)
{
orientation.Normalize();
up.Normalize();
const CVector3D s = orientation.Cross(up);
up = s.Cross(orientation);
m_Orientation._11 = -s.X; m_Orientation._12 = up.X; m_Orientation._13 = orientation.X; m_Orientation._14 = camera.X;
m_Orientation._21 = -s.Y; m_Orientation._22 = up.Y; m_Orientation._23 = orientation.Y; m_Orientation._24 = camera.Y;
m_Orientation._31 = -s.Z; m_Orientation._32 = up.Z; m_Orientation._33 = orientation.Z; m_Orientation._34 = camera.Z;
m_Orientation._41 = 0.0f; m_Orientation._42 = 0.0f; m_Orientation._43 = 0.0f; m_Orientation._44 = 1.0f;
}