1 files changed, 97 insertions, 0 deletions
diff --git a/src/intersect/normals.cpp b/src/intersect/normals.cpp
new file mode 100644
index 0000000..a5ffdbe
--- /dev/null
+++ b/src/intersect/normals.cpp
@@ -0,0 +1,97 @@
+//
+// Created by Michael Foiani on 11/4/23.
+//
+
+#include "raytracer/raytracer.h"
+
+glm::vec3 getConeNormal(
+        glm::vec4 intersectPointObject)
+{
+    if (RayTracer::floatEquals(intersectPointObject.y, -.5f)) // normal for base
+    {
+        return {0.f, -1.f, 0.f};
+    }
+    if (RayTracer::floatEquals(intersectPointObject.y, .5f)) // normal for top
+    {
+        return {0.f, 1.f, 0.f};
+    }
+
+    // gradient in object space for cone top is 2x, r^2 - .5*y, 2z
+    return glm::vec3{
+            2.f * intersectPointObject.x,
+            .25f - .5f * intersectPointObject.y,
+            2.f * intersectPointObject.z
+    };
+}
+
+glm::vec3  getCylinderNormal(
+        glm::vec4 intersectPointObject)
+{
+    if (RayTracer::floatEquals(intersectPointObject.y, -.5f)) // normal for base
+    {
+        return {0.f, -1.f, 0.f};
+    }
+    if (RayTracer::floatEquals(intersectPointObject.y, .5f)) // normal for top
+    {
+        return {0.f, 1.f, 0.f};
+    }
+
+    // gradient in object space for cylinder top is 2x, 0, 2z
+    return glm::vec3{
+            2.f * intersectPointObject.x,
+            0.f,
+            2.f * intersectPointObject.z
+    };
+}
+
+glm::vec3 getCubeNormal(
+        glm::vec4 intersectPointObject)
+{
+    if (RayTracer::floatEquals(intersectPointObject.y, -.5f)) // neg y
+    {
+        return {0.f, -1.f, 0.f};
+    }
+    if (RayTracer::floatEquals(intersectPointObject.y, .5f)) // pos y
+    {
+        return {0.f, 1.f, 0.f};
+    }
+    if (RayTracer::floatEquals(intersectPointObject.x, -.5f)) // neg x
+    {
+        return {-1.f, 0.f, 0.f};
+    }
+    if (RayTracer::floatEquals(intersectPointObject.x, .5f)) // pos x
+    {
+        return {1.f, 0.f, 0.f};
+    }
+    if (RayTracer::floatEquals(intersectPointObject.z, -.5f)) // neg z
+    {
+        return {0.f, 0.f, -1.f};
+    }
+    if (RayTracer::floatEquals(intersectPointObject.z, .5f)) // pos z
+    {
+        return {0.f, 0.f, 1.f};
+    }
+    return glm::vec3(0.f);
+}
+
+glm::vec3 RayTracer::getNormal(
+        glm::vec4 intersectPointObject,
+        const RenderShapeData& shape,
+        const RayTraceScene &scene)
+{
+    switch(shape.primitive.type)
+    {
+        case PrimitiveType::PRIMITIVE_SPHERE:
+            // gradient in object space for sphere is 2x, 2y, 2z
+            return 2.f * intersectPointObject;
+        case PrimitiveType::PRIMITIVE_CONE:
+            return getConeNormal(intersectPointObject);
+        case PrimitiveType::PRIMITIVE_CYLINDER:
+            return getCylinderNormal(intersectPointObject);
+        case PrimitiveType::PRIMITIVE_CUBE:
+            return getCubeNormal(intersectPointObject);
+        case PrimitiveType::PRIMITIVE_MESH:
+            break;
+    }
+    return glm::vec3(0.f);
+}
+\ No newline at end of file