After my last post, a few people pointed out that using heightmaps might be a better approach for this. So I scrapped the previous octree approach, and took a tangent to try out JangaFX's GeoGen, which offer ways to create realistic landscapes, and export meshes, heightmaps and textures out of them. Then that info is imported into the game and wheel collision code looks up the height z based on the x,y of the position, the rest of the code remains the same.
Here's a demonstration of driving the car around the hills:. In order to implement ground collision checking between wheels and a terrain mesh, a performant approach to look up the nearest vertices to the wheel was necessary, so today I implemented an octree to subdivide the terrain mesh in manageable chunks, simple code, around 50 LOC.
The spline system allows for adding parallel points to plot a track, with variable width, generated points then interpolate between the orientation, slope and width. Points are organized in a linked list with a free list. Next steps are adding control points, and rendering a bezier curve.
I implemented some 3D transformation and rotation tools today, including a pixel perfect click-to-select, using a specialized frame buffer that holds object indices. To streamline my own editing I implemented a similar system to Blender's in maniuplating translation and rotation, using keyboard hotkeys like G and R and selecting axes with X,Y and Z keys and orthographic axis views. The initial reason I went into all of this is planning to implement a spline based track editor, but that requires manipulating spline points in 3D space, and this is the basis for that.
Implemented shadow mapping, and basic model lighting to directional light, with a backdrop of a simple sky shader. Also worked on generating the car's textures with material shaders in Blender then baking them onto a single texture.
