From 0786726aa45ea0d0b62dae0e57dbe18c69dae5cb Mon Sep 17 00:00:00 2001
From: faiface <faiface@ksp.sk>
Date: Sat, 3 Dec 2016 20:20:16 +0100
Subject: [PATCH] add line shape
---
graphics.go | 128 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 128 insertions(+)
diff --git a/graphics.go b/graphics.go
index 9176558..1b0231b 100644
--- a/graphics.go
+++ b/graphics.go
@@ -37,6 +37,129 @@ type DrawDeleter interface {
Deleter
}
+// LineColor a line shape (with sharp ends) filled with a single color.
+type LineColor struct {
+ parent pixelgl.Doer
+ color color.Color
+ a, b Vec
+ width float64
+ va *pixelgl.VertexArray
+}
+
+// NewLineColor creates a new line shape between points A and B filled with a single color. Parent is an object
+// that this shape belongs to, such as a window, or a graphics effect.
+func NewLineColor(parent pixelgl.Doer, c color.Color, a, b Vec, width float64) *LineColor {
+ lc := &LineColor{
+ parent: parent,
+ color: c,
+ a: a,
+ b: b,
+ width: width,
+ }
+
+ var format pixelgl.VertexFormat
+ parent.Do(func(ctx pixelgl.Context) {
+ format = ctx.Shader().VertexFormat()
+ })
+
+ var err error
+ lc.va, err = pixelgl.NewVertexArray(
+ parent,
+ format,
+ pixelgl.TriangleStripDrawMode,
+ pixelgl.DynamicUsage,
+ 4,
+ )
+ if err != nil {
+ panic(errors.Wrap(err, "failed to create line"))
+ }
+
+ lc.va.SetVertexAttributeVec4(0, pixelgl.Color, mgl32.Vec4{1, 1, 1, 1})
+ lc.va.SetVertexAttributeVec4(1, pixelgl.Color, mgl32.Vec4{1, 1, 1, 1})
+ lc.va.SetVertexAttributeVec4(2, pixelgl.Color, mgl32.Vec4{1, 1, 1, 1})
+ lc.va.SetVertexAttributeVec4(3, pixelgl.Color, mgl32.Vec4{1, 1, 1, 1})
+
+ lc.setPoints()
+
+ return lc
+}
+
+// setPoints updates the vertex array data according to A, B and width.
+func (lc *LineColor) setPoints() {
+ r := (lc.b - lc.a).Unit().Scaled(lc.width / 2).Rotated(math.Pi / 2)
+ for i, p := range []Vec{lc.a - r, lc.a + r, lc.b - r, lc.b + r} {
+ lc.va.SetVertexAttributeVec2(i, pixelgl.Position, mgl32.Vec2{float32(p.X()), float32(p.Y())})
+ }
+}
+
+// SetColor changes the color of a line.
+func (lc *LineColor) SetColor(c color.Color) {
+ lc.color = c
+}
+
+// Color returns the current color of a line.
+func (lc *LineColor) Color() color.Color {
+ return lc.color
+}
+
+// SetA changes the position of the first endpoint of a line.
+func (lc *LineColor) SetA(a Vec) {
+ lc.a = a
+ lc.setPoints()
+}
+
+// A returns the current position of the first endpoint of a line.
+func (lc *LineColor) A() Vec {
+ return lc.a
+}
+
+// SetB changes the position of the second endpoint of a line.
+func (lc *LineColor) SetB(b Vec) {
+ lc.b = b
+ lc.setPoints()
+}
+
+// B returns the current position of the second endpoint of a line.
+func (lc *LineColor) B() Vec {
+ return lc.b
+}
+
+// SetWidth changes the width of a line.
+func (lc *LineColor) SetWidth(width float64) {
+ lc.width = width
+ lc.setPoints()
+}
+
+// Width returns the current width of a line.
+func (lc *LineColor) Width() float64 {
+ return lc.width
+}
+
+// Draw draws a line transformed by the supplied transforms applied in the reverse order.
+func (lc *LineColor) Draw(t ...Transform) {
+ mat := mgl32.Ident3()
+ for i := range t {
+ mat = mat.Mul3(t[i].Mat3())
+ }
+
+ var shader *pixelgl.Shader
+ lc.parent.Do(func(ctx pixelgl.Context) {
+ shader = ctx.Shader()
+ })
+
+ r, g, b, a := colorToRGBA(lc.color)
+ shader.SetUniformVec4(pixelgl.MaskColor, mgl32.Vec4{r, g, b, a})
+ shader.SetUniformMat3(pixelgl.Transform, mat)
+ shader.SetUniformInt(pixelgl.IsTexture, 0)
+
+ lc.va.Draw()
+}
+
+// Delete destroys a line shape and releases it's video memory. Do not use this shape after calling Delete.
+func (lc *LineColor) Delete() {
+ lc.va.Delete()
+}
+
// PolygonColor is a polygon shape filled with a single color.
type PolygonColor struct {
parent pixelgl.Doer
@@ -259,3 +382,8 @@ func (ec *EllipseColor) Draw(t ...Transform) {
ec.va.Draw()
}
+
+// Delete destroys an ellipse shape and releases it's video memory. Do not use this shape after calling Delete.
+func (ec *EllipseColor) Delete() {
+ ec.va.Delete()
+}
--
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