gglm

README

gglm

Fast OpenGL/Graphics focused Mathematics library in Go inspired by the c++ library glm.

gglm currently has the following:

• Matrices are stored column major
• Vec2, Vec3 and Vec4 structs that implement vector (x,y,z,w) operations
• Mat2, Mat3, Mat4 structs that implement square matrix operations
• Quat struct that implements quaternion operations
• TrMat struct that implements 3D transformation matrix operations
• Many useful geometric functions (e.g. dot product, cross product, vector reflection etc)
• 32-bit scalar operations (e.g. sin32, cos32, equality using epsilon, sqrt32 etc)
• Useful 32-bit constants (e.g. pi, Deg2Rad, Rad2Deg, float32 epsilon etc)
• Simple 'swizzle' interfaces that allow you to do things like .X() or .R() etc.
• Very easy to use with graphics/native APIs as everything is implemented using arrays
• .String() functions on all types for pretty printing

Installation

Note: gglm requires Go 1.18 or higher.

go get github.com/bloeys/gglm

Usage

import "github.com/bloeys/gglm/gglm"

func main() {
	
	// Vec2
	v1 := &gglm.Vec2{Data: [2]float32{1, 2}}
	v2 := &gglm.Vec2{Data: [2]float32{3, 4}}
	println(gglm.DistVec2(v1, v2))
	println(gglm.SqrDistVec2(v2, v1))
	println(v1.Eq(v2))
	v2.Set(1, 2)
	println(v1.Eq(v2))

	// This performs: v1 += v2
	// v1 is returned from the function, so we can chain calls that operate on v1
	newX := v1.Add(v2).X()
	println("newX:", newX)

	// LookAt for a right-handed coordinate system
	camPos := gglm.NewVec3(0, 0, 3)
	worldUp := gglm.NewVec3(0, 1, 0)
	targetPos := gglm.NewVec3(0, 0, 0)
	viewMat := gglm.LookAtRH(camPos, targetPos, worldUp)
	println(viewMat.String())
}

Notes

You can check compiler inlining decisions using go run -gcflags "-m" .. Some functions look a bit weird because we are trying to reduce function complexity so the compiler inlines.