bool
SimpleRenderer::get_inverse_matrix (Matrix44 &result, ustring to, float time)
{
if (to == u_camera || to == u_screen || to == u_NDC || to == u_raster) {
Matrix44 M = m_world_to_camera;
if (to == u_screen || to == u_NDC || to == u_raster) {
// arbitrary clip planes because renderer doesn't do any clipping
float yon = 0.01f;
float hither = 1e5f;
float depthrange = yon - hither;
float tanhalffov = tanf (m_fov * float(M_PI/360.0));
Matrix44 camera_to_screen (1/tanhalffov, 0, 0, 0,
0, 1/tanhalffov, 0, 0,
0, 0, yon/depthrange, 1,
0, 0, -yon*hither/depthrange, 0);
M = M * camera_to_screen;
if (to == u_NDC || to == u_raster) {
Matrix44 screen_to_ndc (0.5f, 0, 0, 0,
0, 0.5f, 0, 0,
0, 0, 1.0f, 0,
-0.5f, -0.5f, 0, 1);
M = M * screen_to_ndc;
if (to == u_raster) {
Matrix44 ndc_to_raster (m_xres, 0, 0, 0,
0, m_yres, 0, 0,
0, 0, 1, 0,
0, 0, 0, 1);
M = M * ndc_to_raster;
}
}
}
result = M;
return true;
}
TransformMap::const_iterator found = m_named_xforms.find (to);
if (found == m_named_xforms.end())
return false;
result = found->second;
result.invert();
return true;
}
void test_d_camera_to_screen() {
auto pos = Vector3f{0, 0, 0};
auto look = Vector3f{0, 0, 1};
auto up = Vector3f{0, 1, 0};
Matrix3x3f n2c = Matrix3x3f::identity();
Matrix3x3f c2n = Matrix3x3f::identity();
Camera camera{1, 1,
&pos[0],
&look[0],
&up[0],
&n2c.data[0][0],
&c2n.data[0][0],
1e-2f,
false};
auto pt = Vector3{0.5, 0.5, 1.0};
auto dx = Real(1);
auto dy = Real(1);
auto d_camera = DCameraInst{};
auto d_pt = Vector3{0, 0, 0};
d_camera_to_screen(camera, pt, dx, dy, d_camera, d_pt);
// Compare with central difference
auto finite_delta = Real(1e-6);
for (int i = 0; i < 3; i++) {
auto delta_pos = pos;
delta_pos[i] += finite_delta;
auto delta_camera = Camera{
1, 1,
&delta_pos[0],
&look[0],
&up[0],
&n2c.data[0][0],
&c2n.data[0][0],
1e-2f,
false};
auto pxy = camera_to_screen(delta_camera, pt);
delta_pos[i] -= 2 * finite_delta;
delta_camera = Camera{
1, 1,
&delta_pos[0],
&look[0],
&up[0],
&n2c.data[0][0],
&c2n.data[0][0],
1e-2f,
false};
auto nxy = camera_to_screen(delta_camera, pt);
auto diff = (sum(pxy - nxy)) / (2 * finite_delta);
equal_or_error(__FILE__, __LINE__, (Real)diff, (Real)d_camera.position[i]);
}
for (int i = 0; i < 3; i++) {
auto delta_look = look;
delta_look[i] += finite_delta;
auto delta_camera = Camera{
1, 1,
&pos[0],
&delta_look[0],
&up[0],
&n2c.data[0][0],
&c2n.data[0][0],
1e-2f,
false};
auto pxy = camera_to_screen(delta_camera, pt);
delta_look[i] -= 2 * finite_delta;
delta_camera = Camera{
1, 1,
&pos[0],
&delta_look[0],
&up[0],
&n2c.data[0][0],
&c2n.data[0][0],
1e-2f,
false};
auto nxy = camera_to_screen(delta_camera, pt);
auto diff = (sum(pxy - nxy)) / (2 * finite_delta);
equal_or_error(__FILE__, __LINE__, (Real)diff, (Real)d_camera.look[i]);
}
for (int i = 0; i < 3; i++) {
auto delta_up = up;
delta_up[i] += finite_delta;
auto delta_camera = Camera{
1, 1,
&pos[0],
&look[0],
&delta_up[0],
&n2c.data[0][0],
&c2n.data[0][0],
1e-2f,
false};
auto pxy = camera_to_screen(delta_camera, pt);
delta_up[i] -= 2 * finite_delta;
delta_camera = Camera{
1, 1,
&pos[0],
&look[0],
&delta_up[0],
&n2c.data[0][0],
&c2n.data[0][0],
1e-2f,
false};
auto nxy = camera_to_screen(delta_camera, pt);
auto diff = (sum(pxy - nxy)) / (2 * finite_delta);
equal_or_error(__FILE__, __LINE__, (Real)diff, (Real)d_camera.up[i]);
}
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
auto delta_camera = camera;
delta_camera.cam_to_ndc(i, j) += finite_delta;
auto pxy = camera_to_screen(delta_camera, pt);
delta_camera.cam_to_ndc(i, j) -= 2 * finite_delta;
auto nxy = camera_to_screen(delta_camera, pt);
auto diff = sum(pxy - nxy) / (2 * finite_delta);
equal_or_error(__FILE__, __LINE__, (Real)diff, (Real)d_camera.cam_to_ndc(i, j));
}
}
}