Question

I would like to know the standard method for resizing my DirectX control. A model is shown in the control, and I want it to be the same size after resize, only more of its environment should be visible.

I managed to do it with resetting the viewport and swapchain buffers, but I could do it another way too (moving the camera), and maybe others I didn’t think of. I just don’t know which is the “best” way.

Answer 1

Changing the viewport size should only show “more” of the viewing area as a matter of changing the aspect ratio. For instance, if the viewport doubles in width and height, the aspect ratio will be the same, therefore the same image will be shown, just larger.

In contrast, moving the camera will change the amount that is viewed, e.g. If you move the camera back, you will see more. However, this may not be what you are looking for. You are physically moving the camera to another location rather than simply changing the view properties.

What you are probably looking for is to change the camera projection properties, which would likely be done using “PerspectiveFovLH”, the input for which is: (“field of view”, “aspect ratio”, “z near plane”, “z far plane”). Widening the field of view (FOV) will allow you to see more of the scene. Changing the aspect ratio will scale that appropriately. Typically the aspect ratio should be the ratio between the screen width and height, and if you want a larger screen to show more overall, scale the FOV by the amount the screen has been re-sized.