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#include "Frustum.h"
#include <math.h>
#include "gl.h"
void FRUSTUM::
GetFrustum() {
float projmatrix[16];
float mvmatrix[16];
float clip[16];
float t;
glGetFloatv(GL_PROJECTION_MATRIX, projmatrix);
glGetFloatv(GL_MODELVIEW_MATRIX, mvmatrix);
// Combine the matrices
clip[0] = mvmatrix[0] * projmatrix[0] + mvmatrix[1] * projmatrix[4] + mvmatrix[2] * projmatrix[8] + mvmatrix[3] * projmatrix[12];
clip[1] = mvmatrix[0] * projmatrix[1] + mvmatrix[1] * projmatrix[5] + mvmatrix[2] * projmatrix[9] + mvmatrix[3] * projmatrix[13];
clip[2] = mvmatrix[0] * projmatrix[2] + mvmatrix[1] * projmatrix[6] + mvmatrix[2] * projmatrix[10] + mvmatrix[3] * projmatrix[14];
clip[3] = mvmatrix[0] * projmatrix[3] + mvmatrix[1] * projmatrix[7] + mvmatrix[2] * projmatrix[11] + mvmatrix[3] * projmatrix[15];
clip[4] = mvmatrix[4] * projmatrix[0] + mvmatrix[5] * projmatrix[4] + mvmatrix[6] * projmatrix[8] + mvmatrix[7] * projmatrix[12];
clip[5] = mvmatrix[4] * projmatrix[1] + mvmatrix[5] * projmatrix[5] + mvmatrix[6] * projmatrix[9] + mvmatrix[7] * projmatrix[13];
clip[6] = mvmatrix[4] * projmatrix[2] + mvmatrix[5] * projmatrix[6] + mvmatrix[6] * projmatrix[10] + mvmatrix[7] * projmatrix[14];
clip[7] = mvmatrix[4] * projmatrix[3] + mvmatrix[5] * projmatrix[7] + mvmatrix[6] * projmatrix[11] + mvmatrix[7] * projmatrix[15];
clip[8] = mvmatrix[8] * projmatrix[0] + mvmatrix[9] * projmatrix[4] + mvmatrix[10] * projmatrix[8] + mvmatrix[11] * projmatrix[12];
clip[9] = mvmatrix[8] * projmatrix[1] + mvmatrix[9] * projmatrix[5] + mvmatrix[10] * projmatrix[9] + mvmatrix[11] * projmatrix[13];
clip[10] = mvmatrix[8] * projmatrix[2] + mvmatrix[9] * projmatrix[6] + mvmatrix[10] * projmatrix[10] + mvmatrix[11] * projmatrix[14];
clip[11] = mvmatrix[8] * projmatrix[3] + mvmatrix[9] * projmatrix[7] + mvmatrix[10] * projmatrix[11] + mvmatrix[11] * projmatrix[15];
clip[12] = mvmatrix[12] * projmatrix[0] + mvmatrix[13] * projmatrix[4] + mvmatrix[14] * projmatrix[8] + mvmatrix[15] * projmatrix[12];
clip[13] = mvmatrix[12] * projmatrix[1] + mvmatrix[13] * projmatrix[5] + mvmatrix[14] * projmatrix[9] + mvmatrix[15] * projmatrix[13];
clip[14] = mvmatrix[12] * projmatrix[2] + mvmatrix[13] * projmatrix[6] + mvmatrix[14] * projmatrix[10] + mvmatrix[15] * projmatrix[14];
clip[15] = mvmatrix[12] * projmatrix[3] + mvmatrix[13] * projmatrix[7] + mvmatrix[14] * projmatrix[11] + mvmatrix[15] * projmatrix[15];
// Right plane
frustum[0][0] = clip[3] - clip[0];
frustum[0][1] = clip[7] - clip[4];
frustum[0][2] = clip[11] - clip[8];
frustum[0][3] = clip[15] - clip[12];
// Left plane
frustum[1][0] = clip[3] + clip[0];
frustum[1][1] = clip[7] + clip[4];
frustum[1][2] = clip[11] + clip[8];
frustum[1][3] = clip[15] + clip[12];
// Bottom plane
frustum[2][0] = clip[3] + clip[1];
frustum[2][1] = clip[7] + clip[5];
frustum[2][2] = clip[11] + clip[9];
frustum[2][3] = clip[15] + clip[13];
// Top plane
frustum[3][0] = clip[3] - clip[1];
frustum[3][1] = clip[7] - clip[5];
frustum[3][2] = clip[11] - clip[9];
frustum[3][3] = clip[15] - clip[13];
// Far plane
frustum[4][0] = clip[3] - clip[2];
frustum[4][1] = clip[7] - clip[6];
frustum[4][2] = clip[11] - clip[10];
frustum[4][3] = clip[15] - clip[14];
// Near plane
frustum[5][0] = clip[3] + clip[2];
frustum[5][1] = clip[7] + clip[6];
frustum[5][2] = clip[11] + clip[10];
frustum[5][3] = clip[15] + clip[14];
}
int FRUSTUM::
CubeInFrustum(float x, float y, float z, float size) {
int c, c2;
for(int i=0; i<6; i++) {
c=0;
if(frustum[i][0] * (x-size) + frustum[i][1] * (y-size) + frustum[i][2] * (z-size) + frustum[i][3] > 0)
c++;
if(frustum[i][0] * (x+size) + frustum[i][1] * (y-size) + frustum[i][2] * (z-size) + frustum[i][3] > 0)
c++;
if(frustum[i][0] * (x-size) + frustum[i][1] * (y+size) + frustum[i][2] * (z-size) + frustum[i][3] > 0)
c++;
if(frustum[i][0] * (x+size) + frustum[i][1] * (y+size) + frustum[i][2] * (z-size) + frustum[i][3] > 0)
c++;
if(frustum[i][0] * (x-size) + frustum[i][1] * (y-size) + frustum[i][2] * (z+size) + frustum[i][3] > 0)
c++;
if(frustum[i][0] * (x+size) + frustum[i][1] * (y-size) + frustum[i][2] * (z+size) + frustum[i][3] > 0)
c++;
if(frustum[i][0] * (x-size) + frustum[i][1] * (y+size) + frustum[i][2] * (z+size) + frustum[i][3] > 0)
c++;
if(frustum[i][0] * (x+size) + frustum[i][1] * (y+size) + frustum[i][2] * (z+size) + frustum[i][3] > 0)
c++;
if(c==0)
return 0;
if(c==8)
c2++;
}
if(c2>=6)
return 2;
else
return 1;
}
int FRUSTUM::
CubeInFrustum(float x, float y, float z, float size, float height) {
int c, c2;
for(int i=0; i<6; i++) {
c=0;
if(frustum[i][0] * (x-size) + frustum[i][1] * (y-height) + frustum[i][2] * (z-size) + frustum[i][3] > 0)
c++;
if(frustum[i][0] * (x+size) + frustum[i][1] * (y-height) + frustum[i][2] * (z-size) + frustum[i][3] > 0)
c++;
if(frustum[i][0] * (x-size) + frustum[i][1] * (y+height) + frustum[i][2] * (z-size) + frustum[i][3] > 0)
c++;
if(frustum[i][0] * (x+size) + frustum[i][1] * (y+height) + frustum[i][2] * (z-size) + frustum[i][3] > 0)
c++;
if(frustum[i][0] * (x-size) + frustum[i][1] * (y-height) + frustum[i][2] * (z+size) + frustum[i][3] > 0)
c++;
if(frustum[i][0] * (x+size) + frustum[i][1] * (y-height) + frustum[i][2] * (z+size) + frustum[i][3] > 0)
c++;
if(frustum[i][0] * (x-size) + frustum[i][1] * (y+height) + frustum[i][2] * (z+size) + frustum[i][3] > 0)
c++;
if(frustum[i][0] * (x+size) + frustum[i][1] * (y+height) + frustum[i][2] * (z+size) + frustum[i][3] > 0)
c++;
if(c==0)
return 0;
if(c==8)
c2++;
}
if(c2>=6)
return 2;
else
return 1;
}
int FRUSTUM::
SphereInFrustum(float x, float y, float z, float radius) {
int c2;
for(int i=0; i<6; i++) {
if(frustum[i][0] * x + frustum[i][1] * y + frustum[i][2] * z + frustum[i][3] > -1*radius)
c2++;
else
return 0;
}
if(c2>=6)
return 2;
else
return 1;
}
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