gfx

Documentation

Overview

Package gfx is a thin abstraction layer for OpenGL.

Index

• Variables
• func Init(ctx gl.Context)
• func NextFrame()
• func Release()
• func SetSize(w, h int)
• func Size() (int, int)
• type Attrib
• type Camera
  • func (c *Camera) Combined() Matrix
  • func (c *Camera) PopTransform()
  • func (c *Camera) PushTransform(m Matrix)
  • func (c *Camera) SetDefaults()
• type CustomInit
  • func Custom(name string, init, release func()) *CustomInit
• type Matrix
  • func Identity() Matrix
  • func MultiplyMatrix(m0, m1 Matrix) Matrix
  • func Perspective(fov, aspect, nearZ, farZ float32) Matrix
  • func RotationX(r float32) Matrix
  • func RotationY(r float32) Matrix
  • func RotationZ(r float32) Matrix
  • func Scale(x, y, z float32) Matrix
  • func Translation(x, y, z float32) Matrix
• type Program
  • func Shader(name, vertex, fragment string) *Program
  • func (p *Program) Attrib(name string) *Attrib
  • func (p *Program) Uniform(name string) *Uniform
• type StaticBuffer
  • func NewStaticBuffer(name string, data []uint8, elements []uint16) *StaticBuffer
  • func (sb *StaticBuffer) Delete()
• type Texture
  • func NewTexture(name string, img image.Image, nearest bool) *Texture
• type Uniform
• type Vector
  • func MultiplyVector(m Matrix, v Vector) Vector

Variables

var (
	// FrameSync is an internal variable.
	FrameSync = make(chan chan struct{}, 1)
)

var GL gl.Context

GL is the OpenGL context.

var Lock sync.Mutex

Lock should be held whenever an operation depends on or modifies global OpenGL state.

var Square = NewStaticBuffer("square", []uint8{
	m1, +1, m1, 1, 0, 0,
	m1, m1, m1, 1, 0, 1,
	+1, m1, +1, 1, 1, 1,
	+1, +1, +1, 1, 1, 0,
}, []uint16{3, 2, 1, 0, 3, 1})

Square is a StaticBuffer containing vertices for a square.

Functions

func Init

func Init(ctx gl.Context)

Init is an internal function that sets up the context.

func NextFrame

func NextFrame()

NextFrame synchronizes a frame boundary.

func Release

func Release()

Release is an internal function that shuts down the context.

func SetSize

func SetSize(w, h int)

SetSize is an internal function.

func Size

func Size() (int, int)

Size returns the current screen size.

Types

type Attrib

type Attrib struct {
	Attrib gl.Attrib
	Name   string
	// contains filtered or unexported fields
}

Attrib is a vertex attribute.

type Camera

type Camera struct {
	Offset      Matrix
	Rotation    Matrix
	Position    Matrix
	Perspective Matrix
	// contains filtered or unexported fields
}

Camera tracks the position and orientation of the 3D camera.

func (*Camera) Combined

func (c *Camera) Combined() Matrix

Combined returns the combined transformation matrix.

func (*Camera) PopTransform

func (c *Camera) PopTransform()

PopTransform removes the last transform added via PushTransform.

func (*Camera) PushTransform

func (c *Camera) PushTransform(m Matrix)

PushTransform adds a transform to the transform stack.

func (*Camera) SetDefaults

func (c *Camera) SetDefaults()

SetDefaults sets the Matrix fields in Camera to default values.

type CustomInit

type CustomInit struct {
	Name string
	// contains filtered or unexported fields
}

CustomInit is a custom OpenGL init/release function pair.

func Custom

func Custom(name string, init, release func()) *CustomInit

Custom registers a CustomInit.

type Matrix

type Matrix [16]float32

Matrix is a 4x4 transformation matrix.

func Identity

func Identity() Matrix

Identity returns the identity matrix.

func MultiplyMatrix

func MultiplyMatrix(m0, m1 Matrix) Matrix

MultiplyMatrix multiplies a matrix by a matrix.

func Perspective

func Perspective(fov, aspect, nearZ, farZ float32) Matrix

Perspective constructs a perspective matrix.

func RotationX

func RotationX(r float32) Matrix

RotationX constructs a rotation matrix over the X axis.

func RotationY

func RotationY(r float32) Matrix

RotationY constructs a rotation matrix over the Y axis.

func RotationZ

func RotationZ(r float32) Matrix

RotationZ constructs a rotation matrix over the Z axis.

func Scale

func Scale(x, y, z float32) Matrix

Scale constructs a scaling matrix.

func Translation

func Translation(x, y, z float32) Matrix

Translation constructs translation matrix.

type Program

type Program struct {
	Name string

	Program gl.Program
	// contains filtered or unexported fields
}

Program is an OpenGL shader.

func Shader

func Shader(name, vertex, fragment string) *Program

Shader registers an OpenGL shader.

func (*Program) Attrib

func (p *Program) Attrib(name string) *Attrib

Attrib gets the location of a vertex attribute.

func (*Program) Uniform

func (p *Program) Uniform(name string) *Uniform

Uniform gets the location of a global variable.

type StaticBuffer

type StaticBuffer struct {
	Name string

	Data    gl.Buffer
	Element gl.Buffer
	Count   int
	// contains filtered or unexported fields
}

StaticBuffer is a convenience layer for OpenGL vertex buffer objects.

func NewStaticBuffer

func NewStaticBuffer(name string, data []uint8, elements []uint16) *StaticBuffer

NewStaticBuffer creates a StaticBuffer.

func (*StaticBuffer) Delete

func (sb *StaticBuffer) Delete()

Delete frees the GPU memory held by StaticBuffer and removes it from the list of buffers.

type Texture

type Texture struct {
	Name    string
	Texture gl.Texture
	// contains filtered or unexported fields
}

Texture is an OpenGL texture.

func NewTexture

func NewTexture(name string, img image.Image, nearest bool) *Texture

NewTexture creates a texture.

type Uniform

type Uniform struct {
	Uniform gl.Uniform
	Name    string
	// contains filtered or unexported fields
}

Uniform is a global variable.

type Vector

type Vector [4]float32

Vector is a 4-component geometric vector of (x, y, z, 1).

func MultiplyVector

func MultiplyVector(m Matrix, v Vector) Vector

MultiplyVector multiplies a matrix by a vector.