432 lines
10 KiB
Go
432 lines
10 KiB
Go
package pixelgl
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import (
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"fmt"
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"image/color"
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"github.com/faiface/glhf"
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"github.com/faiface/mainthread"
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"github.com/faiface/pixel"
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"github.com/go-gl/mathgl/mgl32"
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"github.com/pkg/errors"
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)
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// Canvas is an off-screen rectangular BasicTarget and Picture at the same time, that you can draw
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// onto.
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//
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// It supports TrianglesPosition, TrianglesColor, TrianglesPicture and PictureColor.
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type Canvas struct {
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gf *GLFrame
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shader *glhf.Shader
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cmp pixel.ComposeMethod
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mat mgl32.Mat3
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col mgl32.Vec4
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smooth bool
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sprite *pixel.Sprite
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}
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var _ pixel.ComposeTarget = (*Canvas)(nil)
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// NewCanvas creates a new empty, fully transparent Canvas with given bounds.
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func NewCanvas(bounds pixel.Rect) *Canvas {
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c := &Canvas{
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gf: NewGLFrame(bounds),
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mat: mgl32.Ident3(),
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col: mgl32.Vec4{1, 1, 1, 1},
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}
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c.SetBounds(bounds)
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var shader *glhf.Shader
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mainthread.Call(func() {
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var err error
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shader, err = glhf.NewShader(
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canvasVertexFormat,
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canvasUniformFormat,
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canvasVertexShader,
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canvasFragmentShader,
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)
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if err != nil {
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panic(errors.Wrap(err, "failed to create Canvas, there's a bug in the shader"))
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}
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})
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c.shader = shader
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return c
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}
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// MakeTriangles creates a specialized copy of the supplied Triangles that draws onto this Canvas.
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//
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// TrianglesPosition, TrianglesColor and TrianglesPicture are supported.
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func (c *Canvas) MakeTriangles(t pixel.Triangles) pixel.TargetTriangles {
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return &canvasTriangles{
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GLTriangles: NewGLTriangles(c.shader, t),
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dst: c,
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}
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}
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// MakePicture create a specialized copy of the supplied Picture that draws onto this Canvas.
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//
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// PictureColor is supported.
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func (c *Canvas) MakePicture(p pixel.Picture) pixel.TargetPicture {
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if cp, ok := p.(*canvasPicture); ok {
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return &canvasPicture{
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GLPicture: cp.GLPicture,
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dst: c,
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}
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}
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if gp, ok := p.(GLPicture); ok {
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return &canvasPicture{
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GLPicture: gp,
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dst: c,
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}
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}
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return &canvasPicture{
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GLPicture: NewGLPicture(p),
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dst: c,
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}
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}
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// SetMatrix sets a Matrix that every point will be projected by.
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func (c *Canvas) SetMatrix(m pixel.Matrix) {
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// pixel.Matrix is 3x2 with an implicit 0, 0, 1 row after it. So
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// [0] [2] [4] [0] [3] [6]
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// [1] [3] [5] => [1] [4] [7]
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// 0 0 1 0 0 1
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// since all matrix ops are affine, the last row never changes, and we don't need to copy it
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for i, j := range [...]int{0, 1, 3, 4, 6, 7} {
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c.mat[j] = float32(m[i])
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}
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}
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// SetColorMask sets a color that every color in triangles or a picture will be multiplied by.
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func (c *Canvas) SetColorMask(col color.Color) {
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rgba := pixel.Alpha(1)
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if col != nil {
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rgba = pixel.ToRGBA(col)
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}
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c.col = mgl32.Vec4{
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float32(rgba.R),
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float32(rgba.G),
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float32(rgba.B),
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float32(rgba.A),
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}
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}
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// SetComposeMethod sets a Porter-Duff composition method to be used in the following draws onto
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// this Canvas.
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func (c *Canvas) SetComposeMethod(cmp pixel.ComposeMethod) {
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c.cmp = cmp
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}
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// SetBounds resizes the Canvas to the new bounds. Old content will be preserved.
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func (c *Canvas) SetBounds(bounds pixel.Rect) {
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c.gf.SetBounds(bounds)
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if c.sprite == nil {
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c.sprite = pixel.NewSprite(nil, pixel.Rect{})
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}
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c.sprite.Set(c, c.Bounds())
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//c.sprite.SetMatrix(pixel.IM.Moved(c.Bounds().Center()))
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}
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// Bounds returns the rectangular bounds of the Canvas.
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func (c *Canvas) Bounds() pixel.Rect {
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return c.gf.Bounds()
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}
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// SetSmooth sets whether stretched Pictures drawn onto this Canvas should be drawn smooth or
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// pixely.
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func (c *Canvas) SetSmooth(smooth bool) {
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c.smooth = smooth
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}
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// Smooth returns whether stretched Pictures drawn onto this Canvas are set to be drawn smooth or
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// pixely.
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func (c *Canvas) Smooth() bool {
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return c.smooth
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}
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// must be manually called inside mainthread
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func (c *Canvas) setGlhfBounds() {
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_, _, bw, bh := intBounds(c.gf.Bounds())
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glhf.Bounds(0, 0, bw, bh)
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}
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// must be manually called inside mainthread
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func setBlendFunc(cmp pixel.ComposeMethod) {
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switch cmp {
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case pixel.ComposeOver:
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glhf.BlendFunc(glhf.One, glhf.OneMinusSrcAlpha)
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case pixel.ComposeIn:
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glhf.BlendFunc(glhf.DstAlpha, glhf.Zero)
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case pixel.ComposeOut:
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glhf.BlendFunc(glhf.OneMinusDstAlpha, glhf.Zero)
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case pixel.ComposeAtop:
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glhf.BlendFunc(glhf.DstAlpha, glhf.OneMinusSrcAlpha)
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case pixel.ComposeRover:
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glhf.BlendFunc(glhf.OneMinusDstAlpha, glhf.One)
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case pixel.ComposeRin:
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glhf.BlendFunc(glhf.Zero, glhf.SrcAlpha)
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case pixel.ComposeRout:
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glhf.BlendFunc(glhf.Zero, glhf.OneMinusSrcAlpha)
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case pixel.ComposeRatop:
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glhf.BlendFunc(glhf.OneMinusDstAlpha, glhf.SrcAlpha)
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case pixel.ComposeXor:
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glhf.BlendFunc(glhf.OneMinusDstAlpha, glhf.OneMinusSrcAlpha)
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case pixel.ComposePlus:
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glhf.BlendFunc(glhf.One, glhf.One)
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case pixel.ComposeCopy:
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glhf.BlendFunc(glhf.One, glhf.Zero)
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default:
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panic(errors.New("Canvas: invalid compose method"))
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}
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}
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// Clear fills the whole Canvas with a single color.
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func (c *Canvas) Clear(color color.Color) {
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c.gf.Dirty()
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rgba := pixel.ToRGBA(color)
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// color masking
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rgba = rgba.Mul(pixel.RGBA{
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R: float64(c.col[0]),
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G: float64(c.col[1]),
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B: float64(c.col[2]),
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A: float64(c.col[3]),
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})
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mainthread.CallNonBlock(func() {
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c.setGlhfBounds()
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c.gf.Frame().Begin()
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glhf.Clear(
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float32(rgba.R),
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float32(rgba.G),
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float32(rgba.B),
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float32(rgba.A),
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)
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c.gf.Frame().End()
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})
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}
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// Color returns the color of the pixel over the given position inside the Canvas.
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func (c *Canvas) Color(at pixel.Vec) pixel.RGBA {
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return c.gf.Color(at)
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}
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// Texture returns the underlying OpenGL Texture of this Canvas.
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//
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// Implements GLPicture interface.
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func (c *Canvas) Texture() *glhf.Texture {
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return c.gf.Texture()
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}
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// Frame returns the underlying OpenGL Frame of this Canvas.
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func (c *Canvas) Frame() *glhf.Frame {
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return c.gf.frame
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}
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// SetPixels replaces the content of the Canvas with the provided pixels. The provided slice must be
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// an alpha-premultiplied RGBA sequence of correct length (4 * width * height).
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func (c *Canvas) SetPixels(pixels []uint8) {
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c.gf.Dirty()
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mainthread.Call(func() {
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tex := c.Texture()
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tex.Begin()
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tex.SetPixels(0, 0, tex.Width(), tex.Height(), pixels)
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tex.End()
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})
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}
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// Pixels returns an alpha-premultiplied RGBA sequence of the content of the Canvas.
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func (c *Canvas) Pixels() []uint8 {
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var pixels []uint8
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mainthread.Call(func() {
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tex := c.Texture()
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tex.Begin()
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pixels = tex.Pixels(0, 0, tex.Width(), tex.Height())
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tex.End()
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})
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return pixels
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}
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// Draw draws the content of the Canvas onto another Target, transformed by the given Matrix, just
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// like if it was a Sprite containing the whole Canvas.
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func (c *Canvas) Draw(t pixel.Target, matrix pixel.Matrix) {
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c.sprite.Draw(t, matrix)
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}
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// DrawColorMask draws the content of the Canvas onto another Target, transformed by the given
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// Matrix and multiplied by the given mask, just like if it was a Sprite containing the whole Canvas.
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//
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// If the color mask is nil, a fully opaque white mask will be used causing no effect.
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func (c *Canvas) DrawColorMask(t pixel.Target, matrix pixel.Matrix, mask color.Color) {
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c.sprite.DrawColorMask(t, matrix, mask)
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}
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type canvasTriangles struct {
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*GLTriangles
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dst *Canvas
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}
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func (ct *canvasTriangles) draw(tex *glhf.Texture, bounds pixel.Rect) {
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ct.dst.gf.Dirty()
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// save the current state vars to avoid race condition
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cmp := ct.dst.cmp
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mat := ct.dst.mat
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col := ct.dst.col
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smt := ct.dst.smooth
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mainthread.CallNonBlock(func() {
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ct.dst.setGlhfBounds()
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setBlendFunc(cmp)
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frame := ct.dst.gf.Frame()
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shader := ct.dst.shader
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frame.Begin()
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shader.Begin()
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dstBounds := ct.dst.Bounds()
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shader.SetUniformAttr(canvasBounds, mgl32.Vec4{
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float32(dstBounds.Min.X),
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float32(dstBounds.Min.Y),
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float32(dstBounds.W()),
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float32(dstBounds.H()),
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})
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shader.SetUniformAttr(canvasTransform, mat)
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shader.SetUniformAttr(canvasColorMask, col)
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if tex == nil {
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ct.vs.Begin()
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ct.vs.Draw()
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ct.vs.End()
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} else {
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tex.Begin()
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bx, by, bw, bh := intBounds(bounds)
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shader.SetUniformAttr(canvasTexBounds, mgl32.Vec4{
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float32(bx),
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float32(by),
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float32(bw),
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float32(bh),
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})
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if tex.Smooth() != smt {
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tex.SetSmooth(smt)
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}
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ct.vs.Begin()
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ct.vs.Draw()
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ct.vs.End()
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tex.End()
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}
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shader.End()
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frame.End()
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})
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}
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func (ct *canvasTriangles) Draw() {
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ct.draw(nil, pixel.Rect{})
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}
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type canvasPicture struct {
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GLPicture
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dst *Canvas
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}
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func (cp *canvasPicture) Draw(t pixel.TargetTriangles) {
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ct := t.(*canvasTriangles)
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if cp.dst != ct.dst {
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panic(fmt.Errorf("(%T).Draw: TargetTriangles generated by different Canvas", cp))
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}
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ct.draw(cp.GLPicture.Texture(), cp.GLPicture.Bounds())
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}
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const (
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canvasPosition int = iota
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canvasColor
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canvasTexCoords
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canvasIntensity
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)
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var canvasVertexFormat = glhf.AttrFormat{
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canvasPosition: {Name: "position", Type: glhf.Vec2},
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canvasColor: {Name: "color", Type: glhf.Vec4},
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canvasTexCoords: {Name: "texCoords", Type: glhf.Vec2},
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canvasIntensity: {Name: "intensity", Type: glhf.Float},
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}
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const (
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canvasTransform int = iota
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canvasColorMask
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canvasBounds
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canvasTexBounds
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)
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var canvasUniformFormat = glhf.AttrFormat{
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canvasTransform: {Name: "transform", Type: glhf.Mat3},
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canvasColorMask: {Name: "colorMask", Type: glhf.Vec4},
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canvasBounds: {Name: "bounds", Type: glhf.Vec4},
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canvasTexBounds: {Name: "texBounds", Type: glhf.Vec4},
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}
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var canvasVertexShader = `
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#version 330 core
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in vec2 position;
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in vec4 color;
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in vec2 texCoords;
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in float intensity;
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out vec4 Color;
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out vec2 TexCoords;
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out float Intensity;
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uniform mat3 transform;
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uniform vec4 bounds;
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void main() {
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vec2 transPos = (transform * vec3(position, 1.0)).xy;
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vec2 normPos = (transPos - bounds.xy) / bounds.zw * 2 - vec2(1, 1);
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gl_Position = vec4(normPos, 0.0, 1.0);
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Color = color;
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TexCoords = texCoords;
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Intensity = intensity;
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}
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`
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var canvasFragmentShader = `
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#version 330 core
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in vec4 Color;
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in vec2 TexCoords;
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in float Intensity;
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out vec4 color;
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uniform vec4 colorMask;
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uniform vec4 texBounds;
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uniform sampler2D tex;
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void main() {
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if (Intensity == 0) {
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color = colorMask * Color;
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} else {
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color = vec4(0, 0, 0, 0);
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color += (1 - Intensity) * Color;
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vec2 t = (TexCoords - texBounds.xy) / texBounds.zw;
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color += Intensity * Color * texture(tex, t);
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color *= colorMask;
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}
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}
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`
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