Coordinate system (+Y up, left-handed)

• Normalized Device coordinates: +Y up; (-1, -1) is at the bottom-left corner.
• Framebuffer coordinates: +Y down; (0, 0) is at the top-left corner.
• Texture coordinates: +Y down; (0, 0) is at the top-left corner.

Diagrams (placeholder image)

Why?

You can use other coordinate systems if you need to, of course, by converting between them - but it intentionally won’t be as convienient to use with mach-math. Our coordinate system was chosen largely for consistency with other popular APIs’ defaults:

• WebGPU (+Y up, left-handed)
• Metal (+Y up, left-handed)
• D3D12 (+Y up, left-handed)
• Unity3D (+Y up, left-handed, note their texture coordinates are (0, 0) bottom-left)

Software which doesn’t match our coordinate system:

• Blender (+Z up, right-handed)
• Unreal (+Z up, left-handed)
• OpenGL (+Y up, right-handed)
• Vulkan (-Y up, right-handed)
• Godot (+Y up, right-handed)