Book 1 Chapter 13.2 dev-major: Generating Sample Rays
#1076
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hollasch
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May 31, 2023
This change does several things. Primarily, it's a refinement of the division between the scene class and the camera class. The scene class holds the world description (which includes all scene geometry and lighting) and the camera. It is responsible for using the camera to interrogate the world, using the main render loop (all samples for all pixels). The camera class is responsible for all 2D rendered image parameters, and uses these to generate rays one at a time. The net effect of these changes are: 1. The image_width and aspect_ratio member variables move from the scene class to the camera class. 2. camera::initialize() no longer needs to take the aspect ratio argument. 3. camera::get_image_height() is a new public function that returns the image height, computed from the image width and the desired aspect ratio. 4. `camera::aperture` is now `camera::defocus_diameter`. `camera::lens_radius` is now `camera::defocus_radius`. 5. The scene and camera parameter assignments have been reordered to logical groupings based on the updated mental model. 6. In TheNextWeek/main.cc, we assigned background color, camera up, and focus distance before handing the scene off to the scene generators. There's been at least one case where a reader was confused about the state of the scene object because values were set in two different locations. This saved repeating some lines of code, but the simplicity of assigning everything in one place for each scene is better. These two changes solidify the responsibilities of the two classes in preparation for future changes to the camera class, addressing the following issues: - #546 Confusion surrounding use of the word "aperture" - #682 Camera UV coordinates - handle images with width or height of one - #858 Improve camera.h naming, commentary - #1042 camera::get_ray() function should perform all sample jittering - #1076 Book 1 Chapter 13.2 dev-major: Generating Sample Rays One question left is that now that everything's assigned in the scene generator functions, why not just have them allocate and return the generated scene? I've decided to leave the current approach of mutating the scene -- passed by reference -- purely because it's simpler code. In my opinion, there's not a whole lot of advantage to the returned value approach.
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Fixed in #1144 |
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Discussed in #1075
Originally posted by LollipopFt September 25, 2022
raytracing.github.io/books/RayTracingInOneWeekend.html
Line 3214 in dd6660d
was changed to this:
raytracing.github.io/books/RayTracingInOneWeekend.html
Lines 3387 to 3390 in dd6660d
this flipped the image on the vertical axis such that it is upside down. changing the code to
return ray( origin + offset, - lower_left_corner + s*horizontal + t*vertical - origin - offset + lower_left_corner + s*horizontal + (1-t)*vertical - origin - offset );fixed it.
is it just me?
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