From 23fd33ac75ad610e5992920e594b872407322f47 Mon Sep 17 00:00:00 2001
From: faiface <faiface@ksp.sk>
Date: Sat, 3 Dec 2016 19:51:43 +0100
Subject: [PATCH] add ellipse shape
---
graphics.go | 141 ++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 137 insertions(+), 4 deletions(-)
diff --git a/graphics.go b/graphics.go
index c328976..9176558 100644
--- a/graphics.go
+++ b/graphics.go
@@ -2,6 +2,7 @@ package pixel
import (
"image/color"
+ "math"
"github.com/faiface/pixel/pixelgl"
"github.com/go-gl/mathgl/mgl32"
@@ -45,7 +46,7 @@ type PolygonColor struct {
}
// NewPolygonColor creates a new polygon shape filled with a single color. Parent is an object that this shape belongs to,
-// such as a window, or a graphical effect.
+// such as a window, or a graphics effect.
func NewPolygonColor(parent pixelgl.Doer, c color.Color, points ...Vec) *PolygonColor {
pc := &PolygonColor{
parent: parent,
@@ -59,14 +60,31 @@ func NewPolygonColor(parent pixelgl.Doer, c color.Color, points ...Vec) *Polygon
})
var err error
- pc.va, err = pixelgl.NewVertexArray(parent, format, pixelgl.TriangleFanDrawMode, pixelgl.DynamicUsage, len(points))
+ pc.va, err = pixelgl.NewVertexArray(
+ parent,
+ format,
+ pixelgl.TriangleFanDrawMode,
+ pixelgl.DynamicUsage,
+ len(points),
+ )
if err != nil {
panic(errors.Wrap(err, "failed to create polygon"))
}
for i, p := range points {
- pc.va.SetVertexAttributeVec2(i, pixelgl.Position, mgl32.Vec2{float32(p.X()), float32(p.Y())})
- pc.va.SetVertexAttributeVec4(i, pixelgl.Color, mgl32.Vec4{1, 1, 1, 1})
+ pc.va.SetVertexAttributeVec2(
+ i,
+ pixelgl.Position,
+ mgl32.Vec2{
+ float32(p.X()),
+ float32(p.Y()),
+ },
+ )
+ pc.va.SetVertexAttributeVec4(
+ i,
+ pixelgl.Color,
+ mgl32.Vec4{1, 1, 1, 1},
+ )
}
return pc
@@ -126,3 +144,118 @@ func (pc *PolygonColor) Draw(t ...Transform) {
func (pc *PolygonColor) Delete() {
pc.va.Delete()
}
+
+// EllipseColor is an ellipse shape filled with a single color.
+type EllipseColor struct {
+ parent pixelgl.Doer
+ color color.Color
+ radius Vec
+ fill float64
+ va *pixelgl.VertexArray
+}
+
+// NewEllipseColor creates a new ellipse shape filled with a single color. Parent is an object that this shape belongs to,
+// such as a window, or a graphics effect. Fill should be a number between 0 and 1 which specifies how much of the ellipse will
+// be filled (from the outside). The value of 1 means that the whole ellipse is filled. The value of 0 means that none of the
+// ellipse is filled (which makes the ellipse invisible).
+func NewEllipseColor(parent pixelgl.Doer, c color.Color, radius Vec, fill float64) *EllipseColor {
+ const n = 256
+
+ ec := &EllipseColor{
+ parent: parent,
+ color: c,
+ radius: radius,
+ fill: fill,
+ }
+
+ var format pixelgl.VertexFormat
+ parent.Do(func(ctx pixelgl.Context) {
+ format = ctx.Shader().VertexFormat()
+ })
+
+ var err error
+ ec.va, err = pixelgl.NewVertexArray(
+ parent,
+ format,
+ pixelgl.TriangleStripDrawMode,
+ pixelgl.DynamicUsage,
+ (n+1)*2,
+ )
+ if err != nil {
+ panic(errors.Wrap(err, "failed to create circle"))
+ }
+
+ for k := 0; k < n+1; k++ {
+ i, j := k*2, k*2+1
+ angle := math.Pi * 2 * float64(k%n) / n
+ ec.va.SetVertexAttributeVec2(
+ i,
+ pixelgl.Position,
+ mgl32.Vec2{
+ float32(math.Cos(angle)),
+ float32(math.Sin(angle)),
+ },
+ )
+ ec.va.SetVertexAttributeVec4(
+ i,
+ pixelgl.Color,
+ mgl32.Vec4{1, 1, 1, 1},
+ )
+ ec.va.SetVertexAttributeVec2(
+ j,
+ pixelgl.Position,
+ mgl32.Vec2{
+ float32(math.Cos(angle) * (1 - fill)),
+ float32(math.Sin(angle) * (1 - fill)),
+ },
+ )
+ ec.va.SetVertexAttributeVec4(
+ j,
+ pixelgl.Color,
+ mgl32.Vec4{1, 1, 1, 1},
+ )
+ }
+
+ return ec
+}
+
+// SetColor changes the color of an ellipse.
+func (ec *EllipseColor) SetColor(c color.Color) {
+ ec.color = c
+}
+
+// Color returns the current color of an ellipse.
+func (ec *EllipseColor) Color() color.Color {
+ return ec.color
+}
+
+// SetRadius sets the radius (which can be different in X and Y axis) of an ellipse.
+func (ec *EllipseColor) SetRadius(radius Vec) {
+ ec.radius = radius
+}
+
+// Radius returns the current radius of an ellipse.
+func (ec *EllipseColor) Radius() Vec {
+ return ec.radius
+}
+
+// Draw dras an ellipse transformed by the supplied transforms applied in the reverse order.
+func (ec *EllipseColor) Draw(t ...Transform) {
+ mat := mgl32.Ident3()
+ for i := range t {
+ mat = mat.Mul3(t[i].Mat3())
+ }
+ mat = mat.Mul3(mgl32.Scale2D(float32(ec.radius.X()), float32(ec.radius.Y())))
+
+ var shader *pixelgl.Shader
+ ec.parent.Do(func(ctx pixelgl.Context) {
+ shader = ctx.Shader()
+ })
+
+ r, g, b, a := colorToRGBA(ec.color)
+ shader.SetUniformVec4(pixelgl.MaskColor, mgl32.Vec4{r, g, b, a})
+ shader.SetUniformMat3(pixelgl.Transform, mat)
+ shader.SetUniformInt(pixelgl.IsTexture, 0)
+
+ ec.va.Draw()
+}
--
GitLab