WorldToScreen 16:9

worldtoscreen.cpp

/**********************************
Credits to OGC for world2screen
**********************************/

inline float VectorAngle(const vec3_t a, const vec3_t b)
{
	float length_a = VectorLength(a);
	float length_b = VectorLength(b);
	float length_ab = length_a*length_b;
	if (length_ab == 0.0) { return 0.0; }
	else { return (float)(acos(DotProduct(a, b) / length_ab) * (180.f / M_PI)); }
}

void MakeVector(const vec3_t ain, vec3_t vout)
{
	float pitch;
	float yaw;
	float tmp;

	pitch = (float)(ain[0] * M_PI / 180);
	yaw = (float)(ain[1] * M_PI / 180);
	tmp = (float)cos(pitch);

	vout[0] = (float)(-tmp * -cos(yaw));
	vout[1] = (float)(sin(yaw)*tmp);
	vout[2] = (float)-sin(pitch);
}

void VectorRotateX(const vec3_t in, float angle, vec3_t out)
{
	float a, c, s;

	a = (float)(angle * M_PI / 180);
	c = (float)cos(a);
	s = (float)sin(a);
	out[0] = in[0];
	out[1] = c*in[1] - s*in[2];
	out[2] = s*in[1] + c*in[2];
}

void VectorRotateY(const vec3_t in, float angle, vec3_t out)
{
	float a, c, s;

	a = (float)(angle * M_PI / 180);
	c = (float)cos(a);
	s = (float)sin(a);
	out[0] = c*in[0] + s*in[2];
	out[1] = in[1];
	out[2] = -s*in[0] + c*in[2];
}

void VectorRotateZ(const vec3_t in, float angle, vec3_t out)
{
	float a, c, s;

	a = (float)(angle * M_PI / 180);
	c = (float)cos(a);
	s = (float)sin(a);
	out[0] = c*in[0] - s*in[1];
	out[1] = s*in[0] + c*in[1];
	out[2] = in[2];
}

bool CDraw::worldToScreen(vec3_t w, int *x, int *y) {
	vec3_t aim;
	vec3_t newaim;
	vec3_t view;
	vec3_t tmp;
	float num, fov;

	VectorCopy(sky.cgame.refdef->vieworg, tmp);
	VectorSubtract(w, tmp, aim);
	MakeVector(sky.cgame.refdefViewAngles, view);

	fov = sky.cgame.refdef->fov_x;
	fov += (9.f / 40.f) * fov + (3.f / 4.f) + 1.f; // Ignoring 16:10 as for now

	if (VectorAngle(view, aim) > (fov / 1.8))
		return false;

	VectorRotateZ(aim, -sky.cgame.refdefViewAngles[YAW], newaim);
	VectorRotateY(newaim, -sky.cgame.refdefViewAngles[PITCH], tmp);
	VectorRotateX(tmp, -sky.cgame.refdefViewAngles[ROLL], newaim);

	if (newaim[0] <= 0)
		return false;

	num = (float)((640.0f / newaim[0]) * (120.0 / fov - 1.0 / 3.0));

	*x = (int)(640 - num * newaim[1]);
	*y = (int)(360 - num * newaim[2]);

	BOUND_VALUE(*x, 0, 1280);
	BOUND_VALUE(*y, 0, 720);

	return true;
}