gl

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 Go to latest Published: Nov 11, 2015 License: Apache-2.0 Imports: 6 Imported by: 0

Documentation

Overview

Package gl provides a more Go friendly OpenGL API

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func ActiveTexture 

func ActiveTexture(id int)

ActiveTexture sets the texture slot with the passed id as the currently active one.

func BindFragDataLocation 

func BindFragDataLocation(p Program, cn int, name string)

func BlendFunc 

func BlendFunc(sFactor, dFactor Factor)

BlendFunc sets the factors to be used when blending.

func BlendFuncSeparate 

func BlendFuncSeparate(sFactorRGB, dFactorRGB, sFactorA, dFactorA Factor)

BlendFuncSeparate sets the factors to be used when blending.

func BlitFramebuffer 

func BlitFramebuffer(sx0, sy0, sx1, sy1, dx0, dy0, dx1, dy1 int, mask ClearFlags, filter TextureValue)

func CheckError 

func CheckError()

CheckError panics if there has been an error reported to the context. This is normally not a cheap call so shouldn't be used in production.

func Clear 

func Clear(flags ClearFlags)

Clear clears the buffers specified by the passed flags.

func ClearBuffer 

func ClearBuffer(buffer TargetBuffer, drawBuffer int, values []float32)

func ClearColor 

func ClearColor(r, g, b, a float32)

ClearColor sets the color the color buffer should be cleared to when Clear is called with the color flag.

func ClearStencil 

func ClearStencil(i int)

ClearStencil clears the stencil buffer will the passed value.

func ColorMask 

func ColorMask(r, g, b, a bool)

ColorMask sets whether each color channel be the written too.

func CullFace 

func CullFace(face Face)

CullFace sets the face to be culled by the gpu.

func DebugLog 

func DebugLog()

DebugLog enables OpenGL's debug messages and logs them to stdout.

func DepthFunc 

func DepthFunc(f Func)

DepthFunc sets the function used to decide whether to cull a pixel when depth testing

func DepthMask 

func DepthMask(f bool)

DepthMask sets whether the depth buffer can be written too.

func Disable 

func Disable(flag Flag)

Disable disables the passed flag.

func DrawArrays 

func DrawArrays(ty DrawType, offset, count int)

DrawArrays draws the passed number of triangles starting at the passed offset using data from the currently bound buffer(s). The DrawType specifies how the shapes (triangles, lines etc) will be formed from the data.

func DrawBuffers 

func DrawBuffers(bufs []Attachment)

func DrawElements 

func DrawElements(ty DrawType, count int, dty Type, offset int)

func Enable 

func Enable(flag Flag)

Enable enables the passed flag.

func Flush 

func Flush()

Flush flushes all commands in the queue and waits for completion.

func FrontFace 

func FrontFace(dir FaceDirection)

FrontFace sets the direction of vertices used to specify the front face (e.g. for culling).

func Init 

func Init()

Init inits the gl library. This should be called once a context is ready.

func MultiDrawElements 

func MultiDrawElements(ty DrawType, count []int32, dty Type, offset []uintptr)

func StencilFunc 

func StencilFunc(f Func, ref, mask int)

StencilFunc sets the function to be used when comparing with the stencil buffer.

func StencilMask 

func StencilMask(mask int)

StencilMask sets the value to be written to the stencil buffer on success.

func StencilOp 

func StencilOp(op, fail, pass Op)

StencilOp sets the operation to be executed depending on the result of the stencil test.

func UnbindFramebuffer 

func UnbindFramebuffer()

func UnbindFramebufferDraw 

func UnbindFramebufferDraw()

func UnbindFramebufferRead 

func UnbindFramebufferRead()

func Viewport 

func Viewport(x, y, width, height int)

Viewport sets the size of the viewport of this context.

Types

type Access 

type Access uint32

Access states how a value will be accesed by the program. 

const (
	// ReadOnly states that the returned value will only be read.
	ReadOnly Access = gl.READ_ONLY
	// WriteOnly states that the returned value will only be written
	// to.
	WriteOnly Access = gl.WRITE_ONLY
)

type Attachment 

type Attachment uint32
const (
	ColorAttachment0 Attachment = gl.COLOR_ATTACHMENT0
	ColorAttachment1 Attachment = gl.COLOR_ATTACHMENT1
	ColorAttachment2 Attachment = gl.COLOR_ATTACHMENT2
	DepthAttachment  Attachment = gl.DEPTH_ATTACHMENT
)

type Attribute 

type Attribute int32

Attribute is a per-a-vertex value that can be passed into the program.

func (Attribute) Disable 

func (a Attribute) Disable()

Disable disables the attribute for use in rendering.

func (Attribute) Enable 

func (a Attribute) Enable()

Enable enables the attribute for use in rendering.

func (Attribute) Pointer 

func (a Attribute) Pointer(size int, ty Type, normalized bool, stride, offset int)

Pointer is used to specify the format of the data in the buffer. The data will be uploaded as floats.

func (Attribute) PointerInt 

func (a Attribute) PointerInt(size int, ty Type, stride, offset int)

PointerInt is used to specify the format of the data in the buffer. The data will be uploaded as integers.

type Buffer 

type Buffer struct {
	// contains filtered or unexported fields
}

Buffer is a storage for vertex data.

func CreateBuffer 

func CreateBuffer() Buffer

CreateBuffer allocates a new Buffer. If the allocation fails IsValid will return false.

func (Buffer) Bind 

func (b Buffer) Bind(target BufferTarget)

Bind makes the buffer the currently active one for the given target. This will allow it to be the source of operations that act on a buffer (Data, Map etc). If the buffer is already bound then this does nothing.

func (Buffer) Data 

func (b Buffer) Data(data []byte, usage BufferUsage)

Data uploads the passed data to the gpu to be placed in this buffer. The usage specifies how the program plans to use this buffer.

func (*Buffer) Delete 

func (b *Buffer) Delete()

Delete deallocates the buffer and any stored data. IsValid will return false after this call.

func (Buffer) IsValid 

func (b Buffer) IsValid() bool

IsValid returns whether this Buffer is still valid. A Buffer will become invalid after Delete is called.

func (Buffer) Map 

func (b Buffer) Map(access Access, length int) []byte

Map maps the memory in the buffer on the gpu to memory which the program can access. The access flag will specify how the program plans to use the returned data. Unmapped must be called to return the data to the gpu.

Warning: the passed length value is not checked in anyway so it is possible to overrun the memory. It is up to the program to ensure this length is valid.

func (Buffer) Unmap 

func (b Buffer) Unmap()

Unmap returns mapped memory for the buffer, as returned by Map, to the gpu so that it can be used in draw operations.

type BufferTarget 

type BufferTarget uint32

BufferTarget is a target for a buffer to be bound to. 

const (
	// ArrayBuffer is a buffer target intended for vertex data.
	ArrayBuffer        BufferTarget = gl.ARRAY_BUFFER
	ElementArrayBuffer BufferTarget = gl.ELEMENT_ARRAY_BUFFER
)

type BufferUsage 

type BufferUsage uint32

BufferUsage states how a buffer is going to be used by the program. 

const (
	// StaticDraw marks the buffer as 'not going to change' after the
	// initial data upload to be rendered by the gpu.
	StaticDraw BufferUsage = gl.STATIC_DRAW
	// DynamicDraw marks the buffer as 'changed frequently' during the
	// course of the program whilst being rendered by the gpu.
	DynamicDraw BufferUsage = gl.DYNAMIC_DRAW
	// StreamDraw marks the buffer as 'changed every frame' whilst being
	// rendered by the gpu.
	StreamDraw BufferUsage = gl.STREAM_DRAW
)

type ClearFlags 

type ClearFlags uint32

ClearFlags is a set of flags to mark what should be cleared during a Clear call. 

const (
	// ColorBufferBit marks the color buffer to be cleared
	ColorBufferBit ClearFlags = gl.COLOR_BUFFER_BIT
	// DepthBufferBit marks the depth buffer to be cleared
	DepthBufferBit ClearFlags = gl.DEPTH_BUFFER_BIT
	// StencilBufferBit marks the stencil buffer to be cleared
	StencilBufferBit ClearFlags = gl.STENCIL_BUFFER_BIT
)

type DrawType 

type DrawType uint32

DrawType is used to specify how the vertices will be handled to draw. 

const (
	// Triangles treats each set of 3 vertices as a triangle
	Triangles DrawType = gl.TRIANGLES
	// LineStrip means the previous vertex connects to the next
	// one in a continuous strip.
	LineStrip DrawType = gl.LINE_STRIP
	// Lines treats each set of 2 vertices as a line
	Lines DrawType = gl.LINES
	// Points treats each vertex as a point
	Points DrawType = gl.POINTS
)

type Face 

type Face uint32

Face specifies a face to act on. 

const (
	Back  Face = gl.BACK
	Front Face = gl.FRONT
)

Valid faces

type FaceDirection 

type FaceDirection uint32

FaceDirection is used to specify an order of vertices, normally used to set which is considered to be the front face. 

const (
	ClockWise        FaceDirection = gl.CW
	CounterClockWise FaceDirection = gl.CCW
)

Valid directions for vertices for faces.

type Factor 

type Factor uint32

Factor is used in blending 

const (
	SrcAlpha         Factor = gl.SRC_ALPHA
	OneMinusSrcAlpha Factor = gl.ONE_MINUS_SRC_ALPHA
	OneFactor        Factor = gl.ONE
	ZeroFactor       Factor = gl.ZERO
)

Valid factors

type Flag 

type Flag uint32

Flag is a setting that can be enabled or disabled on the context. 

const (
	DepthTest    Flag = gl.DEPTH_TEST
	CullFaceFlag Flag = gl.CULL_FACE
	StencilTest  Flag = gl.STENCIL_TEST
	Blend        Flag = gl.BLEND
	DebugOutput  Flag = gl.DEBUG_OUTPUT
	Multisample  Flag = gl.MULTISAMPLE
)

Valid flags

type Framebuffer 

type Framebuffer struct {
	// contains filtered or unexported fields
}

func NewFramebuffer 

func NewFramebuffer() Framebuffer

func (Framebuffer) Bind 

func (f Framebuffer) Bind()

func (Framebuffer) BindDraw 

func (f Framebuffer) BindDraw()

func (Framebuffer) BindRead 

func (f Framebuffer) BindRead()

func (Framebuffer) Check 

func (f Framebuffer) Check()

func (Framebuffer) Delete 

func (f Framebuffer) Delete()

func (Framebuffer) ReadBuffer 

func (f Framebuffer) ReadBuffer(a Attachment)

func (Framebuffer) Texture2D 

func (f Framebuffer) Texture2D(attachment Attachment, texTarget TextureTarget, tex Texture, level int)

type Func 

type Func uint32

Func is a function to be preformed on two values. 

const (
	Never       Func = gl.NEVER
	Less        Func = gl.LESS
	LessOrEqual Func = gl.LEQUAL
	Greater     Func = gl.GREATER
	Always      Func = gl.ALWAYS
	Equal       Func = gl.EQUAL
)

Functions

type Op 

type Op uint32

Op is an operation to be applied (depending on the method used) 

const (
	Replace Op = gl.REPLACE
	Keep    Op = gl.KEEP
	Zero    Op = gl.ZERO
)

Valid operations

type Program 

type Program uint32

Program is a collection of shaders which will be run on draw operations.

func CreateProgram 

func CreateProgram() Program

CreateProgram allocates a new program.

func (Program) AttachShader 

func (p Program) AttachShader(s Shader)

AttachShader attaches the passed shader to the program.

func (Program) AttributeLocation 

func (p Program) AttributeLocation(name string) Attribute

AttributeLocation returns the attribute with the given name in the program. 

func (p Program) Link()

Link links the program's shaders.

func (Program) UniformLocation 

func (p Program) UniformLocation(name string) Uniform

UniformLocation returns the uniform with the given name in the program.

func (Program) Use 

func (p Program) Use()

Use sets this shader as the active shader. If this shader is already active this does nothing.

type Shader 

type Shader uint32

Shader is code to be run on the gpu at a specific stage in the pipeline.

func CreateShader 

func CreateShader(t ShaderType) Shader

CreateShader creates a new shader of the specifed type.

func (Shader) Compile 

func (s Shader) Compile()

Compile compiles the shader.

func (Shader) InfoLog 

func (s Shader) InfoLog() string

InfoLog returns the log from compiling the shader.

func (Shader) Parameter 

func (s Shader) Parameter(param ShaderParameter) int

Parameter returns the integer value of the parameter for this shader.

func (Shader) Source 

func (s Shader) Source(src string)

Source sets the source of the shader.

type ShaderParameter 

type ShaderParameter uint32

ShaderParameter is a parameter that can set or read from a shader. 

const (
	CompileStatus ShaderParameter = gl.COMPILE_STATUS
	InfoLogLength ShaderParameter = gl.INFO_LOG_LENGTH
)

Valid shader parameters.

type ShaderType 

type ShaderType uint32

ShaderType is type of shader to be used, different types run at different stages in the pipeline. 

const (
	VertexShader   ShaderType = gl.VERTEX_SHADER
	FragmentShader ShaderType = gl.FRAGMENT_SHADER
	GeometryShader ShaderType = gl.GEOMETRY_SHADER
)

Valid shader types.

type TargetBuffer 

type TargetBuffer uint32
const (
	Color TargetBuffer = gl.COLOR
)

type Texture 

type Texture struct {
	// contains filtered or unexported fields
}

Texture is a buffer of data used by fragment shaders to produce color.

func CreateTexture 

func CreateTexture() Texture

CreateTexture allocates a new texture.

func (Texture) Bind 

func (t Texture) Bind(target TextureTarget)

Bind binds the texture to the passed target, if the texture is already bound then this does nothing.

func (Texture) Delete 

func (t Texture) Delete()

func (Texture) Get 

func (t Texture) Get(level int, format TextureFormat, ty Type, pixels []byte)

func (Texture) Image2D 

func (t Texture) Image2D(level, width, height int, format TextureFormat, ty Type, pix []byte)

Image2D uploads a 2D texture to the GPU.

func (Texture) Image2DEx 

func (t Texture) Image2DEx(level, width, height int, internalFormat, format TextureFormat, ty Type, pix []byte)

Image2DEx uploads a 2D texture to the GPU.

func (Texture) Image2DSample 

func (t Texture) Image2DSample(samples, width, height int, format TextureFormat, fixed bool)

Image2DEx uploads a 2D texture to the GPU.

func (Texture) Image3D 

func (t Texture) Image3D(level, width, height, depth int, format TextureFormat, ty Type, pix []byte)

Image3D uploads a 3D texture to the GPU.

func (Texture) Parameter 

func (t Texture) Parameter(param TextureParameter, val TextureValue)

Parameter sets a parameter on the texture to passed value.

func (Texture) SubImage2D 

func (t Texture) SubImage2D(level int, x, y, width, height int, format TextureFormat, ty Type, pix []byte)

SubImage2D updates a region of a 2D texture.

func (Texture) SubImage3D 

func (t Texture) SubImage3D(level, x, y, z, width, height, depth int, format TextureFormat, ty Type, pix []byte)

SubImage3D updates a region of a 3D texture.

type TextureFormat 

type TextureFormat uint32

TextureFormat is the format of a texture either internally or to be uploaded. 

const (
	Red              TextureFormat = gl.RED
	RGB              TextureFormat = gl.RGB
	RGBA             TextureFormat = gl.RGBA
	RGBA8            TextureFormat = gl.RGBA8
	RGBA16F          TextureFormat = gl.RGBA16F
	R16F             TextureFormat = gl.R16F
	DepthComponent24 TextureFormat = gl.DEPTH_COMPONENT24
	DepthComponent   TextureFormat = gl.DEPTH_COMPONENT
)

Valid texture formats.

type TextureParameter 

type TextureParameter uint32

TextureParameter is a parameter that can be read or set on a texture. 

const (
	TextureMinFilter TextureParameter = gl.TEXTURE_MIN_FILTER
	TextureMagFilter TextureParameter = gl.TEXTURE_MAG_FILTER
	TextureWrapS     TextureParameter = gl.TEXTURE_WRAP_S
	TextureWrapT     TextureParameter = gl.TEXTURE_WRAP_T
	TextureMaxLevel  TextureParameter = gl.TEXTURE_MAX_LEVEL
)

Valid texture parameters.

type TextureTarget 

type TextureTarget uint32

TextureTarget is a target were a texture can be bound to. 

const (
	Texture2D            TextureTarget = gl.TEXTURE_2D
	Texture2DMultisample TextureTarget = gl.TEXTURE_2D_MULTISAMPLE
	Texture2DArray       TextureTarget = gl.TEXTURE_2D_ARRAY
	Texture3D            TextureTarget = gl.TEXTURE_3D
)

Valid texture targets.

type TextureValue 

type TextureValue int32

TextureValue is a value that be set on a texture's parameter. 

const (
	Nearest              TextureValue = gl.NEAREST
	Linear               TextureValue = gl.LINEAR
	LinearMipmapLinear   TextureValue = gl.LINEAR_MIPMAP_LINEAR
	LinearMipmapNearest  TextureValue = gl.LINEAR_MIPMAP_NEAREST
	NearestMipmapNearest TextureValue = gl.NEAREST_MIPMAP_NEAREST
	NearestMipmapLinear  TextureValue = gl.NEAREST_MIPMAP_LINEAR
	ClampToEdge          TextureValue = gl.CLAMP_TO_EDGE
)

Valid texture values.

type Type 

type Type uint32

Type is a type of data used by various operations. 

const (
	UnsignedByte  Type = gl.UNSIGNED_BYTE
	UnsignedShort Type = gl.UNSIGNED_SHORT
	UnsignedInt   Type = gl.UNSIGNED_INT
	Short         Type = gl.SHORT
	Float         Type = gl.FLOAT
)

Valid types.

type Uniform 

type Uniform int32

Uniform is a per-a-draw value that can be passed into the program.

func (Uniform) Float 

func (u Uniform) Float(val float32)

Float sets the value of the uniform to the passed float.

func (Uniform) Float2 

func (u Uniform) Float2(x, y float32)

Float2 sets the value of the uniform to the passed floats.

func (Uniform) Float3 

func (u Uniform) Float3(x, y, z float32)

Float3 sets the value of the uniform to the passed floats.

func (Uniform) Float4 

func (u Uniform) Float4(x, y, z, w float32)

Float3 sets the value of the uniform to the passed floats.

func (Uniform) FloatMutli 

func (u Uniform) FloatMutli(a []float32)

func (Uniform) FloatMutliRaw 

func (u Uniform) FloatMutliRaw(a interface{}, l int)

func (Uniform) Int 

func (u Uniform) Int(val int)

Int sets the value of the uniform to the passed integer.

func (Uniform) Int3 

func (u Uniform) Int3(x, y, z int)

Int3 sets the value of the uniform to the passed integers.

func (Uniform) IntV 

func (u Uniform) IntV(v ...int)

IntV sets the value of the uniform to the passed integer array.

func (Uniform) Matrix4 

func (u Uniform) Matrix4(matrix *mgl32.Mat4)

Matrix4 sets the value of the uniform to the passed matrix.

func (Uniform) Matrix4Multi 

func (u Uniform) Matrix4Multi(matrix []mgl32.Mat4)

Matrix4 sets the value of the uniform to the passed matrix.

type VertexArray 

type VertexArray struct {
	// contains filtered or unexported fields
}

VertexArray is used to store state needed to render vertices. This includes buffers, the format of the buffers and enabled attributes.

func CreateVertexArray 

func CreateVertexArray() VertexArray

CreateVertexArray allocates a new VertexArray. If the allocation fails then IsValid will return false.

func (VertexArray) Bind 

func (va VertexArray) Bind()

Bind marks the VertexArray as the currently active one, this means buffers/the format of the buffers etc will be bound to this VertexArray. If this vertex array is already bound then this will do nothing.

func (*VertexArray) Delete 

func (va *VertexArray) Delete()

Delete deallocates the VertexArray. This does not free any attached buffers. IsValid will return false after this call.

func (VertexArray) IsValid 

func (va VertexArray) IsValid() bool

IsValid returns whether this VertexArray is still valid. A VertexArray will become invalid after Delete is called.

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