camera-vertices

camera-vertices.c

void
gkPrepareCameraProp(GkCamera * __restrict cam) {
  mat4    projViewInv;
  vec4   *vert;
  vec3    min, max;
  int32_t i;

  vert = cam->vertices;

  glm_mat4_inv(cam->projView, projViewInv);

  glm_mat4_mulv(projViewInv, (vec4){-1.0f, -1.0f, -1.0f, 1.0f}, vert[0]);
  glm_mat4_mulv(projViewInv, (vec4){-1.0f,  1.0f, -1.0f, 1.0f}, vert[1]);
  glm_mat4_mulv(projViewInv, (vec4){ 1.0f, -1.0f, -1.0f, 1.0f}, vert[2]);
  glm_mat4_mulv(projViewInv, (vec4){ 1.0f,  1.0f, -1.0f, 1.0f}, vert[3]);

  glm_mat4_mulv(projViewInv, (vec4){-1.0f, -1.0f,  1.0f, 1.0f}, vert[4]);
  glm_mat4_mulv(projViewInv, (vec4){-1.0f,  1.0f,  1.0f, 1.0f}, vert[5]);
  glm_mat4_mulv(projViewInv, (vec4){ 1.0f, -1.0f,  1.0f, 1.0f}, vert[6]);
  glm_mat4_mulv(projViewInv, (vec4){ 1.0f,  1.0f,  1.0f, 1.0f}, vert[7]);

  memset(min, 0, sizeof(vec3));
  memset(max, 0, sizeof(vec3));

  for (i = 0; i < 8; i++) {
    glm_vec4_scale(vert[i], 1.0f / vert[i][3], vert[i]);

    if (vert[i][0] < min[0])
      min[0] = vert[i][0];
    else if (vert[i][0] > max[0])
      max[0] = vert[i][0];

    if (vert[i][1] < min[1])
      min[1] = vert[i][1];
    else if (vert[i][1] > max[1])
      max[1] = vert[i][1];

    if (vert[i][2] < min[2])
      min[2] = vert[i][2];
    else if (vert[i][2] > max[2])
      max[2] = vert[i][2];
  }

  glm_vec_copy(min, cam->bbox.min);
  glm_vec_copy(max, cam->bbox.max);
  glm_vec_center(min, max, cam->bbox.center);
  cam->bbox.radius = glm_vec_distance(min, max) * 0.5f;
}