https://github.com/roy-fokker/sdl3-text

Learning how to use SDL-TTF with SDL-GPU api
https://github.com/roy-fokker/sdl3-text

cmake cpp-modules cpp23 sdl3 sdl3-gpu sdl3-ttf

Last synced: 6 months ago
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Learning how to use SDL-TTF with SDL-GPU api

• Host: GitHub
• URL: https://github.com/roy-fokker/sdl3-text
• Owner: Roy-Fokker
• License: mit
• Created: 2025-04-15T14:55:29.000Z (over 1 year ago)
• Default Branch: main
• Last Pushed: 2025-04-24T20:31:06.000Z (about 1 year ago)
• Last Synced: 2025-04-29T15:26:25.802Z (about 1 year ago)
• Topics: cmake, cpp-modules, cpp23, sdl3, sdl3-gpu, sdl3-ttf
• Language: CMake
• Homepage:
• Size: 62.5 KB
• Stars: 1
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: readme.md
  • License: LICENSE

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README

          
# SDL3 + C++23 Project to render text

## Goal

Learn how to use SDL3 to render text to screen while using SDL3-GPU.

Assume we can use SDL3-TTF to draw the text.

## Uses

- CPM.CMake for package management

- Ninja-Build for build engine

- CMake 4.0+ with cmakepresets for configuration and build

  - There is an issue, on my machine, with CMake 4.0. It fails to configure properly. Use v4.0.1

- C++ modules enabled

- Uses C++ Standard Library modules

  - MSVC (Windows only)

  - Clang (Linux with libc++ only)

- Focuses on SDL3 GPU

- HLSL for all shaders

## to be figured out

- Intellisense, ccls and clangd cannot handle modules so don't work correctly

## CMake commands

VSCode will run these automatically.

- On Windows

```shell

  # Configure Project

  cmake --preset windows-default

  # Build Project, parameter order matters

  cmake --build --preset windows-debug

```

- On Linux

```shell

  # Configure Project

  cmake --preset linux-default

  # Build Project, parameter order matters

  cmake --build --preset linux-debug

```

## Example project dependencies

Uses following libraries retrieved from their project repos by CPM.CMake

- SDL3, obviously

- GLM, for math

- DXC, either from Windows SDK (for D3D12 backend) or Vulkan SDK (for Vulkan backend)

## Basic notes on code structure

- As much as is possible, functions will not take ownership of pointers to objects.

- Where able, all SDL GPU types are wrapped into std::unique_ptr with custom deleters, so they self clean on destruction.

### Function flow

- main

  - Application Init

    - SDL init

    - TTF init

    - Window create

    - GPU create

    - High Resolution Clock

  - Application Run

    - Scene Init

      - Set Clear Colour

      - Create Pipeline

        - Load Vertex Shader

        - Load Fragment/Pixel Shader

        - Set Vertex Attributes

        - Set Vertex Buffer Descriptions

        - Build Pipeline

      - Create TTF GPU Text Engine

      - Create TTF Font

      - Create TTF Text run with Text Engine and Font

      - Get Text mesh and texture from TTF Text

      - Create Perspective projection matrix

      - Create Text mesh transform matrix

    - Loop till quit event

      - Handle SDL events

        - Handle Keyboard and Mouse Inputs

      - Update Application State

      - Draw

        - Acquire GPU Command Buffer

        - Acquire Next swapchain image

        - Create Color Target

        - Begin GPU Render Pass

          - Bind Pipeline

          - Bind Vertex and Index buffers

          - Bind Texture and Sampler

          - Draw Indexed Primitives

        - End GPU Render Pass

        - Submit Command Buffer

      - Clock Tick

    - Clean/Destroy Scene

  - Application Stop

    - Destroy GPU

    - Destroy Window

    - TTF Quit

    - SDL Quit

## references

- Building on linux with Clang and libc++ for module support, https://mattbolitho.github.io/posts/vcpkg-with-libcxx/

- CMake 3.30 magic encantations, https://www.kitware.com/import-std-in-cmake-3-30/

- CMake module compilations, https://www.kitware.com/import-cmake-the-experiment-is-over/