Javascript raytracing with shadows

Question

I am having trouble with getting my raytracing to produce shadow. I also need help with how to build a Cornell box in Javascript. If you know of any tutors that can help with this, I would appreciate it.

Answer 1

Ray tracing in JavaScript can be used to simulate shadows by tracing rays from the light sources in the scene to the objects in the scene. Here's a simplified explanation of how it works:

1. Scene setup: Define the objects in the scene, including their shapes, positions, and material properties. Also, define the light sources in the scene.

2. Ray casting: For each pixel in the rendered image, cast a primary ray from the camera's position through that pixel. This primary ray represents the line of sight from the camera to the scene.

3. Intersection testing: Test if the primary ray intersects with any objects in the scene. This is typically done by checking for ray-object intersections using techniques like ray-sphere or ray-triangle intersection algorithms.

4. Shadow rays: If the primary ray intersects with an object, cast shadow rays from that intersection point toward each light source in the scene.

5. Intersection testing for shadows: Test if the shadow rays intersect with any other objects in the scene. If a shadow ray intersects with another object before reaching the light source, it means that the object is blocking the light, creating a shadow at the intersection point.

6. Calculation of illumination: Calculate the illumination at the intersection point using the material properties of the object and the lighting conditions. This involves considering factors like diffuse and specular reflection, ambient lighting, and any other relevant lighting models.

7. Recursive ray tracing: If the material of the object is reflective or transparent, additional rays can be traced recursively to simulate reflection and refraction effects. This process continues until a termination condition is met.

8. Accumulate and render: Repeat steps 2-7 for each pixel in the image, accumulating the calculated colors for each pixel. Finally, render the accumulated colors to create the final image with shadows.

Note that ray tracing can be computationally expensive, especially in real-time scenarios, due to the need to trace multiple rays and perform intersection tests for each pixel. However, advancements in hardware acceleration (such as WebGL) and optimization techniques can help improve performance.

JavaScript libraries like Three.js and Babylon.js provide ray tracing capabilities, making it easier to implement shadow effects in your web-based applications.