https://github.com/bchao1/go-render

🎦 3D renderer in Go.
https://github.com/bchao1/go-render

3d 3d-graphics camera computer-graphics geometry go golang light rasterization rendering texture

Last synced: 6 months ago
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🎦 3D renderer in Go.

• Host: GitHub
• URL: https://github.com/bchao1/go-render
• Owner: bchao1
• Created: 2020-08-12T06:40:56.000Z (about 5 years ago)
• Default Branch: master
• Last Pushed: 2020-08-18T09:42:46.000Z (about 5 years ago)
• Last Synced: 2025-03-26T08:37:05.412Z (7 months ago)
• Topics: 3d, 3d-graphics, camera, computer-graphics, geometry, go, golang, light, rasterization, rendering, texture
• Language: Go
• Homepage:
• Size: 66.8 MB
• Stars: 19
• Watchers: 2
• Forks: 1
• Open Issues: 1
• Metadata Files:
  • Readme: readme.md

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README

          
# go-render

A simple renderer (rasterization-based) written in Go.



    

    





    



The OG [tinyrenderer](https://github.com/ssloy/tinyrenderer) project helped me alot. It's amazing stuff, and I highly recommend everyone check it out.

## Usage

The code is pretty self-contained. I only used a 3rd-party library `imaging` to flip images vertically. 







To do your custom render:

```

go run render.go  

```

For example, see `run.sh`:

```

go run data/obj/bunny_2.obj data/textures/bunny_texture.jpg

```

Of course, you can first build `render.go`, and then run the executable:

```

go build render.go

./render  

```

### Customization

You could also play with some other parameters (light direction, camera position, spectral lighting, and etc) in `render.go`.

- `eye`: The camera position. Default is (0, 0, 1).

- `center`: Position the camera is looking at Default is (0, 0, 0).

- `up`: The vertical axis of the camera. Default is (0, 1, 0), which is the y-axis.

- `lightDir`: Light ray direction. Default is (0, 0, -1), which means the light is parellel to user's eye.

- `specCoeff`: Weight of spectral lighting. (For the shiny dragon above, I used 20.0)

- `imageHeight`: Pixel height of output image.

- `background`: Whether to color output image background black. If not, then output image has transparent background.

- `outFile`: Render output file path.

- `defaultFill`: If no texture is specified, use this color.

## Demo 

> Basics

|||

|--|--|

|Wireframe|Triangle rasterization|

|![img](./results/basic/wireframe.png)|![img](./results/basic/triangle_color.png)|

> Shading

|Flat shading|Gouraud shading|Phong shading|

|--|--|--|

|![img](./results/shading/flat.png)|![img](./results/shading/gouraud.png)|![img](./results/shading/phong.png)|

|![img](./results/shading/flat_detail.png)|![img](./results/shading/gouraud_detail.png)|![img](./results/shading/phong_detail.png)|

> Perspective

|||||

|--|--|--|--|

|![img](results/project/project_5.0.png)|![img](results/project/project_2.0.png)|![img](results//project/project_1.5.png)|![img](results/project/project_1.0.png)|

> Textures

Kudos to the author of [this article](https://blenderartists.org/t/uv-unwrapped-stanford-bunny-happy-spring-equinox/1101297) for providing custom Stanford bunny texture files.

|Colored|Terracotta|

|--|--|

|![img](./results/textures/bunny_color.png)|![img](./results/textures/bunny_terracotta.png)|

> Camera

|||||

|--|--|--|--|

|![img](./results/camera/1.png)|![img](./results/camera/2.png)|![img](./results/camera/3.png)|![img](./results/camera/4.png)|

|![img](./results/camera/8.png)|![img](./results/camera/7.png)|![img](./results/camera/6.png)|![img](./results/camera/5.png)|

> Light

|||||

|--|--|--|--|

|![img](./results/light/-10.png)|![img](./results/light/-5.png)|![img](./results/light/-2.png)|![img](./results/light/-1.png)|

![img](./results/light/10.png)|![img](./results/light/5.png)|![img](./results/light/2.png)|![img](./results/light/1.png)|

> Specular lighting

The stronger specular lighting is, the more "glossy" the object surface becomes. I simply used uniform power for each pixel since specular intensity is not specified in my texture files.

|No specular|Some specular (used)|Intense specular|

|--|--|--|

|![img](./results/specular/none.png)|![img](./results/specular/moderate.png)|![img](./results/specular/strong.png)|

## `.obj` sources

- https://www.prinmath.com/csci5229/OBJ/index.html

- https://people.sc.fsu.edu/~jburkardt/data/obj/obj.html

- https://groups.csail.mit.edu/graphics/classes/6.837/F03/models/

- https://casual-effects.com/data/

- https://github.com/alecjacobson/common-3d-test-models