actual raytracing (almost)

src/renderer/object_tracer.cpp

@@ -1,18 +1,59 @@
 #include "object_tracer.hpp"
 #include "scene/object.hpp"
 
+#include <cmath>
+#include <maths.hpp>
 #include <yolo/yolo.hpp>
 
 namespace inferno::graphics::rays {
 
+bool triangle_ray_collide(Ray* ray, float* t, glm::vec3 vertex0, glm::vec3 vertex1, glm::vec3 vertex2)
+{
+    glm::vec3 edge1, edge2, h, s, q;
+    float a, f, u, v;
+    edge1 = vertex1 - vertex0;
+    edge2 = vertex2 - vertex0;
+    h = glm::cross(ray->Direction, edge2);
+    a = glm::dot(edge1, h);
+    if (a > -helpers::EPSILON && a < helpers::EPSILON)
+        return false; // This ray is parallel to this triangle.
+    f = 1.0 / a;
+    s = ray->Origin - vertex0;
+    u = f * glm::dot(s, h);
+    if (u < 0.0 || u > 1.0)
+        return false;
+    q = glm::cross(s, edge1);
+    v = f * glm::dot(ray->Direction, q);
+    if (v < 0.0 || u + v > 1.0)
+        return false;
+    // At this stage we can compute t to find out where the intersection point is on the line.
+    *t = f * glm::dot(edge2, q);
+    if (*t > helpers::EPSILON) // ray intersection
+        return true;
+    else // This means that there is a line intersection but not a ray intersection.
+        return false;
+}
+
 HitInfo* object_ray_collide(scene::SceneObject* object, Ray* ray)
 {
     HitInfo* info = nullptr;
     for (auto* mesh : scene::scene_object_get_meshs(object)) {
         // extract triangles and loop over them, if there is a hit - we return
+        const uint32_t* ind;
+        const float* verts;
+        const float* norms;
+        mesh->getIndicies(&ind);
+        mesh->getVerticies(&verts, &norms);
+
+        float t = INFINITY;
+        for (int i = 0; i < mesh->getIndexCount(); i += 3) {
+            uint32_t index = ind[i];
+            glm::vec3 a = {  };
+            glm::vec3 b = {  };
+            glm::vec3 c = {  };
+        }
     }
     return info;
 }
 
 }
-