src/engine/scene.c

   1 #include <stdlib.h>
   2
   3 #include "engine/logger.h"
   4
   5 #include "scene.h"
   6
   7 Scene* currentScene = NULL;
   8
   9 static Transform identity = { .a1 = 1.0f, .a2 = 0.0f, .a3 = 0.0f, .a4 = 0.0f,
  10                               .b1 = 0.0f, .b2 = 1.0f, .b3 = 0.0f, .b4 = 0.0f,
  11                               .c1 = 0.0f, .c2 = 0.0f, .c3 = 1.0f, .c4 = 0.0f,
  12                               .d1 = 0.0f, .d2 = 0.0f, .d3 = 0.0f, .d4 = 1.0f };
  13
  14 void multiply(Transform* transform, Transform by) {
  15         GLfloat* a = (GLfloat*) &by;
  16         GLfloat* b = (GLfloat*) transform;
  17
  18         for (size_t row = 0; row < 4; ++row) {
  19                 for (size_t col = 0; col < 4; ++col) {
  20                         b[(row * 4) + col] =
  21                                 a[(row * 4) + 0] * b[(0 * 4) + col]
  22                                 + a[(row * 4) + 1] * b[(1 * 4) + col]
  23                                 + a[(row * 4) + 2] * b[(2 * 4) + col]
  24                                 + a[(row * 4) + 3] * b[(3 * 4) + col];
  25                 }
  26         }
  27 }
  28
  29 void translate(Transform* transform, Vector3D vec) {
  30         multiply(transform, (Transform) { .a1 = 1.0f, .a2 = 0.0f, .a3 = 0.0f, .a4 = vec.x,
  31                                       .b1 = 0.0f, .b2 = 1.0f, .b3 = 0.0f, .b4 = vec.y,
  32                                       .c1 = 0.0f, .c2 = 0.0f, .c3 = 1.0f, .c4 = vec.z,
  33                                       .d1 = 0.0f, .d2 = 0.0f, .d3 = 0.0f, .d4 = 1.0f });
  34 }
  35
  36 Scene* newScene() {
  37         Scene* scene = malloc(sizeof(Scene));
  38         *scene = (Scene) { .parent = NULL,
  39                            .numChildren = 0u,
  40                            .children = NULL,
  41                            .transform = identity,
  42                            .solid = NULL };
  43         return scene;
  44 }
  45
  46 void insertChildScene(Scene* scene, Scene* newChild) {
  47         if (!scene || !newChild) {
  48                 return;
  49         }
  50         if (newChild->parent) {
  51                 logError(
  52                         "Cannot insert scene 0x%p as child of 0x%p, because it is already child of 0x%p",
  53                         newChild,
  54                         scene,
  55                         newChild->parent);
  56                 return;
  57         }
  58
  59         scene->children = realloc(scene->children, ++(scene->numChildren) * sizeof(Scene*));
  60         scene->children[scene->numChildren - 1] = newChild;
  61
  62         newChild->parent = scene;
  63 }