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/* This file is part of the Spring engine (GPL v2 or later), see LICENSE.html */
#include "Frustum.h"
#include "Rendering/GL/myGL.h"
#undef far // avoid collision with windef.h
void Frustum::InversePlanes ()
{
std::vector<Plane>::iterator p;
for(p=planes.begin(); p!=planes.end(); ++p) {
p->Inverse ();
}
}
// find the box vertices to compare against the plane
static void BoxPlaneVerts (const Vector3& min, const Vector3& max, const Vector3& plane,
Vector3& close, Vector3& far)
{
if(plane.x > 0) { close.x = min.x; far.x = max.x; }
else { close.x = max.x; far.x = min.x; }
if(plane.y > 0) { close.y = min.y; far.y = max.y; }
else { close.y = max.y; far.y = min.y; }
if(plane.z > 0) { close.z = min.z; far.z = max.z; }
else { close.z = max.z; far.z = min.z; }
}
void Frustum::CalcCameraPlanes (Vector3 *cbase, Vector3 *cright, Vector3* cup, Vector3* cfront, float tanHalfFov, float aspect)
{
planes.resize(5);
planes[0].SetVec (*cfront);
planes[0].CalcDist (*cbase + *cfront);
float m = 200.0f;
base = *cbase + *cfront * m;
up = *cup , right = *cright;
up *= tanHalfFov * m;
right *= tanHalfFov * m * aspect;
front = *cfront;
pos [0] = base + right + up; // rightup
pos [1] = base + right - up; // rightdown
pos [2] = base - right - up; // leftdown
pos [3] = base - right + up; // leftup
base = *cbase;
planes[1].MakePlane (base, pos[2], pos[3]); // left
planes[2].MakePlane (base, pos[3], pos[0]); // up
planes[3].MakePlane (base, pos[0], pos[1]); // right
planes[4].MakePlane (base, pos[1], pos[2]); // down
right.ANormalize();
up.ANormalize();
front.ANormalize();
}
void Frustum::Draw ()
{
if (base.x==0.0f) return;
glDisable(GL_CULL_FACE);
/* if (keys[SDLK_t]) {
glBegin(GL_LINES);
glColor3ub (255,0,0);
glVertex3fv((float*)&base);
glVertex3fv((float*)&(base+front*100));
glEnd();
glBegin(GL_LINES);
glColor3ub (0,255,0);
glVertex3fv((float*)&base);
glVertex3fv((float*)&(base+right*100));
glEnd();
glBegin(GL_LINES);
glColor3ub (0,0,255);
glVertex3fv((float*)&base);
glVertex3fv((float*)&(base+up*100));
glEnd();
}else{*/
glBegin (GL_LINES);
for (int a=0;a<4;a++) {
glVertex3f (base.x, base.y, base.z);
glVertex3f (pos[a].x, pos[a].y, pos[a].z);
}
glEnd();
glBegin (GL_LINE_LOOP);
for (int a=0;a<4;a++) {
glVertex3fv ((float*)&pos[a]);
}
glEnd();
//}
glColor3ub(255,255,255);
}
Frustum::VisType Frustum::IsBoxVisible (const Vector3& min, const Vector3& max)
{
bool full = true;
Vector3 c,f;
std::vector<Plane>::iterator p;
for(p=planes.begin(); p!=planes.end(); ++p)
{
BoxPlaneVerts (min, max, p->GetVector(), c, f);
const float dc = p->Dist(&c);
const float df = p->Dist(&f);
if(dc < 0.0f || df < 0.0f) full=false;
if(dc < 0.0f && df < 0.0f) return Outside;
}
return full ? Inside : Partial;
}
Frustum::VisType Frustum::IsPointVisible (const Vector3& pt)
{
std::vector<Plane>::const_iterator p;
for(p=planes.begin(); p!=planes.end(); ++p) {
float d = p->Dist (&pt);
if (d < 0.0f) return Outside;
}
return Inside;
}
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