mirror of
https://github.com/Relintai/godot_voxel.git
synced 2024-12-22 01:26:50 +01:00
124 lines
3.4 KiB
C++
124 lines
3.4 KiB
C++
#include "voxel_raycast.h"
|
|
#include <core/math/math_funcs.h>
|
|
|
|
bool voxel_raycast(
|
|
Vector3 ray_origin,
|
|
Vector3 ray_direction,
|
|
VoxelPredicate predicate,
|
|
void *predicate_context,
|
|
real_t max_distance,
|
|
Vector3i &out_hit_pos,
|
|
Vector3i &out_prev_pos) {
|
|
|
|
const float g_infinite = 9999999;
|
|
|
|
// Equation : p + v*t
|
|
// p : ray start position (ray.pos)
|
|
// v : ray orientation vector (ray.dir)
|
|
// t : parametric variable = a distance if v is normalized
|
|
|
|
// This raycasting technique is described here :
|
|
// http://www.cse.yorku.ca/~amana/research/grid.pdf
|
|
|
|
// Note : the grid is assumed to have 1-unit square cells.
|
|
|
|
ERR_FAIL_COND_V(predicate == 0, false);
|
|
ERR_FAIL_COND_V(ray_direction.is_normalized() == false, false); // Must be normalized
|
|
|
|
/* Initialisation */
|
|
|
|
// Voxel position
|
|
Vector3i hit_pos(
|
|
Math::floor(ray_origin.x),
|
|
Math::floor(ray_origin.y),
|
|
Math::floor(ray_origin.z));
|
|
Vector3i hit_prev_pos = hit_pos;
|
|
|
|
// Voxel step
|
|
const int xi_step = ray_direction.x > 0 ? 1 : ray_direction.x < 0 ? -1 : 0;
|
|
const int yi_step = ray_direction.y > 0 ? 1 : ray_direction.y < 0 ? -1 : 0;
|
|
const int zi_step = ray_direction.z > 0 ? 1 : ray_direction.z < 0 ? -1 : 0;
|
|
|
|
// Parametric voxel step
|
|
const real_t tdelta_x = xi_step != 0 ? 1.f / Math::abs(ray_direction.x) : g_infinite;
|
|
const real_t tdelta_y = yi_step != 0 ? 1.f / Math::abs(ray_direction.y) : g_infinite;
|
|
const real_t tdelta_z = zi_step != 0 ? 1.f / Math::abs(ray_direction.z) : g_infinite;
|
|
|
|
// Parametric grid-cross
|
|
real_t tcross_x; // At which value of T we will cross a vertical line?
|
|
real_t tcross_y; // At which value of T we will cross a horizontal line?
|
|
real_t tcross_z; // At which value of T we will cross a depth line?
|
|
|
|
// X initialization
|
|
if (xi_step != 0) {
|
|
if (xi_step == 1)
|
|
tcross_x = (Math::ceil(ray_origin.x) - ray_origin.x) * tdelta_x;
|
|
else
|
|
tcross_x = (ray_origin.x - Math::floor(ray_origin.x)) * tdelta_x;
|
|
} else
|
|
tcross_x = g_infinite; // Will never cross on X
|
|
|
|
// Y initialization
|
|
if (yi_step != 0) {
|
|
if (yi_step == 1)
|
|
tcross_y = (Math::ceil(ray_origin.y) - ray_origin.y) * tdelta_y;
|
|
else
|
|
tcross_y = (ray_origin.y - Math::floor(ray_origin.y)) * tdelta_y;
|
|
} else
|
|
tcross_y = g_infinite; // Will never cross on X
|
|
|
|
// Z initialization
|
|
if (zi_step != 0) {
|
|
if (zi_step == 1)
|
|
tcross_z = (Math::ceil(ray_origin.z) - ray_origin.z) * tdelta_z;
|
|
else
|
|
tcross_z = (ray_origin.z - Math::floor(ray_origin.z)) * tdelta_z;
|
|
} else
|
|
tcross_z = g_infinite; // Will never cross on X
|
|
|
|
/* Iteration */
|
|
|
|
do {
|
|
hit_prev_pos = hit_pos;
|
|
if (tcross_x < tcross_y) {
|
|
if (tcross_x < tcross_z) {
|
|
// X collision
|
|
//hit.prevPos.x = hit.pos.x;
|
|
hit_pos.x += xi_step;
|
|
if (tcross_x > max_distance)
|
|
return false;
|
|
tcross_x += tdelta_x;
|
|
} else {
|
|
// Z collision (duplicate code)
|
|
//hit.prevPos.z = hit.pos.z;
|
|
hit_pos.z += zi_step;
|
|
if (tcross_z > max_distance)
|
|
return false;
|
|
tcross_z += tdelta_z;
|
|
}
|
|
} else {
|
|
if (tcross_y < tcross_z) {
|
|
// Y collision
|
|
//hit.prevPos.y = hit.pos.y;
|
|
hit_pos.y += yi_step;
|
|
if (tcross_y > max_distance)
|
|
return false;
|
|
tcross_y += tdelta_y;
|
|
} else {
|
|
// Z collision (duplicate code)
|
|
//hit.prevPos.z = hit.pos.z;
|
|
hit_pos.z += zi_step;
|
|
if (tcross_z > max_distance)
|
|
return false;
|
|
tcross_z += tdelta_z;
|
|
}
|
|
}
|
|
|
|
} while (!predicate(hit_pos, predicate_context));
|
|
|
|
out_hit_pos = hit_pos;
|
|
out_prev_pos = hit_prev_pos;
|
|
|
|
return true;
|
|
}
|