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Natural Terrain

Ian Dong, Zack Oon, Colin Steidtmann, Satvik Muddana

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Goal → Recreate Beautiful Natural Effects

Starting Point�https://github.com/LiamHz/atlas

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Our Best Recreations

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Fog

Implemented a shader to render fog in a scene based on the distance of the fragment to the camera

Exponential Squared Fog

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Grass

Gif goes here

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Grass Billboards!

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Grass Positioning & Shading

In more detail, for each chunk of our terrain, we collected all vertices corresponding to where there should be grass and created a VAO for it, storing the vertices in a buffer that we sent to the GPU. Then, for each render loop, we checked which terrain chunks were within the rendering distance and bound the associated VAO for each chunk, drawing the corresponding grass vertices. We also calculated and sent the model, view, and projection matrices to our shader. The matrices helped transform our terrain coordinates into scene coordinates. Our vertex shader simply lifted the vertex positions slightly above the surface to prevent the grass from being buried. These vertices were then passed to our geometry shader. The geometry shader generated a series of rectangular billboards by emitting new vertices and transforming them based on the transformation matrices we provided in the render loop. It also provided texture UV coordinates for our fragment shader. Our fragment shader took each pixel that was within one of the billboards created by our geometry shader and used the interpolated UV coordinates to sample which part of our grass texture to show, or not show as we didn’t want to output parts of our grass texture image that weren’t actual grass blades.

Satvik’s little tidbit:

Hey I’m Satvik! We also implemented a different kind of grass shader for the snowy terrain. The three main differences between the regular grass and our snowy grass are that one: the snowy grass only appears at the specific y-values representing the height of the snowy zone. Two: the snowy grass only appears sparsely to resemble a more realistic snowy terrain based on a specific probability factor. Finally: we created a separate texture itself differing from the original grass to give it a more snowy look.

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Sky Box

Create cube map of 6 textures
Sample cube based on direction vector

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Water

The start

Water plane added

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Water

Reflection + Refraction

The reflection’s camera position.

image credit: ThinMatrix’s water tutorial

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Water

Distortion + Movement

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Unfortunately, Nature is More Than Pixels

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Base Terrain Found on GitHub

https://github.com/LiamHz/atlas

Challenge:

The repository didn’t include OpenGL and all the dependencies directly

Our Solution:

Make a CMake file for the project and include the dependencies directly in it

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Character Movement

The starter code didn’t come with up/down keys, so we added up/down keys

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Struggles and Next Steps

Still working on adding grass, had difficulty figuring out how to get the grass coordinates inputted into our shader
Planning on adding realistic snow
Need to work on our shading and blending code
Water issues:

Texture mapping of the surroundings, reflection, refraction, and transparency will be added to the water for the final product
Future changes will be made to create local 2D bounding boxes for islands of water (optimization)
There are currently visible issues with Z-fighting