t_mat4 mat4_view_lookat(t_vec3 eye, t_vec3 targ, t_vec3 up)
{
t_mat4 out;
t_vec3 zaxis;
t_vec3 xaxis;
t_vec3 yaxis;
zaxis = vec3_normal(vec3_sub(eye, targ));
xaxis = vec3_normal(vec3_cross(up, zaxis));
yaxis = vec3_cross(zaxis, xaxis);
out = mat4_ident();
out.m[0] = xaxis.x;
out.m[1] = yaxis.x;
out.m[2] = zaxis.x;
out.m[4] = xaxis.y;
out.m[5] = yaxis.y;
out.m[6] = zaxis.y;
out.m[8] = xaxis.z;
out.m[9] = yaxis.z;
out.m[10] = zaxis.z;
out.m[12] = -vec3_dot(xaxis, eye);
out.m[13] = -vec3_dot(yaxis, eye);
out.m[14] = -vec3_dot(zaxis, eye);
return (out);
}
/*
Create a new buffer object from an array of vec3s for pts, and vec3s for texture coordinates.
Faces is an array of 3 shorts for each face.
*/
BUFFER_T *buffer_new(float pts[][3], float tex[][3], short faces[][3], int numpts, int numfaces)
{
int i;
float normals[numpts][3];
BUFFER_T *buf;
NEW(buf);
for(i=0; i<numpts; i++)
{
normals[i][0]=0;
normals[i][1]=0;
normals[i][2]=1;
}
for(i=0; i<numfaces; i++)
{
int a = faces[i][0];
int b = faces[i][1];
int c = faces[i][2];
float tmp[3];
float tmp2[3];
float n[3];
vec3_sub(tmp,pts[b],pts[a]);
vec3_sub(tmp2,pts[c],pts[a]);
vec3_cross(n,tmp,tmp2);
vec3_normal(n,n);
vec3_copy(normals[a],n);
vec3_copy(normals[b],n);
vec3_copy(normals[c],n);
}
float B[3*3*numpts];
for(i=0; i<numpts; i++)
{
for(int j=0; j<3; j++)
{
B[i*3*3+j]=pts[i][j];
B[i*3*3+3+j]=tex[i][j];
B[i*3*3+6+j]=normals[i][j];
}
}
buf->ntris=numfaces;
glGenBuffers(1,&buf->vbuf);
glBindBuffer(GL_ARRAY_BUFFER, buf->vbuf);
glBufferData(GL_ARRAY_BUFFER, 36*numpts, B, GL_STATIC_DRAW);
buf->vbuf_num = numpts;
glGenBuffers(1,&buf->ebuf);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buf->ebuf);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, 6*numfaces, faces, GL_STATIC_DRAW);
buf->ebuf_num = numfaces*3;
return buf;
}
// ************************************************************
void RTPolygon::GenerateNormal(void) {
vNormal = vec3_normal(verts[0], verts[1], verts[2], true);
}