https://github.com/overv/mantlehellotriangle

An implementation of Hello Triangle using the Mantle API on Windows
https://github.com/overv/mantlehellotriangle

Last synced: 4 months ago
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An implementation of Hello Triangle using the Mantle API on Windows

• Host: GitHub
• URL: https://github.com/overv/mantlehellotriangle
• Owner: Overv
• Created: 2015-03-19T18:51:50.000Z (over 11 years ago)
• Default Branch: master
• Last Pushed: 2020-09-06T09:14:42.000Z (almost 6 years ago)
• Last Synced: 2025-04-06T06:34:39.630Z (about 1 year ago)
• Language: C
• Size: 43 KB
• Stars: 92
• Watchers: 12
• Forks: 11
• Open Issues: 3
• Metadata Files:
  • Readme: README.md

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README

          
Introduction

------------

This is an effort to implement Hello Triangle using the Mantle API by using the

API reference and reverse engineering public Mantle demos.

See this blog post for more information:

https://medium.com/@Overv/implementing-hello-triangle-in-mantle-4302450fbcd2

Approach

--------

The [reference](http://www.amd.com/Documents/Mantle-Programming-Guide-and-API-Reference.pdf)

is used as primary resource, because it contains a full API reference and some

sample code. Unfortunately it misses a lot of the constant definitions, like

`GR_API_VERSION`, but these can be determined by creating a proxy mantle64.dll

that logs calls and the contents of structs. This approach is currently used

on the [Star Swarm Stress Test](http://store.steampowered.com/app/267130/) to

figure out what calls and data are needed to render a triangle on the screen.

Other values, like `GR_MAX_HEAPS` can be figured out by querying for the struct

size with functions like `grGetObjectInfo`.

The intermediate language used for Mantle shaders is a subset of AMD IL, for

which CodeXL contains [a compiler](http://developer.amd.com/community/blog/2014/05/16/codexl-game-developers-analyze-hlsl-gcn/).

The disassembly it outputs is incorrect, but the bytecode itself is valid.

Mantle appears to accept this code without problems.

Status

------

The code is capable of creating a window using the SDL library, clearing it to

black and rendering a per-vertex colored triangle using Mantle.

![Preview of running program](http://i.imgur.com/r5PxoRv.png)

The vertex shader reads the position (`float4`) and color (`float4`) from a

buffer using the `SV_VertexID` built-in variable. Each buffer is assigned a

memory view into GPU memory filled with the following data:

    float vertices[] = {

        // Positions

        0.0, 0.5, 0.0, 1.0,

        0.5, -0.5, 0.0, 1.0,

        -0.5, -0.5, 0.0, 1.0,

        // Colors

        1.0, 0.0, 0.0, 1.0,

        0.0, 1.0, 0.0, 1.0,

        0.0, 0.0, 1.0, 1.0

    };

Shader compilation

------------------

Shaders are written in HLSL and compiled to AMD Intermediate Language using

the `CodeXLAnalyzer.exe` tool included in CodeXL using the `--il` flag. A batch

script for doing this is included in the `shaders` folder. The hex code on the

right side can then be converted to a binary file using the `output2binary.py`

script, which takes the IL output file name as parameter. The binaries can then

be loaded into Mantle using `grCreateShader`, as is demonstrated in the code.

License

-------

    Copyright (c) 2015 Alexander Overvoorde

    Permission is hereby granted, free of charge, to any person obtaining a copy

    of this software and associated documentation files (the "Software"), to

    deal in the Software without restriction, including without limitation the

    rights to use, copy, modify, merge, publish, distribute, sublicense, and/or

    sell copies of the Software, and to permit persons to whom the Software is

    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in

    all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS

    IN THE SOFTWARE.