From e79a8c37e60ff00111fe91cd97bf5ad15bc9f9a8 Mon Sep 17 00:00:00 2001
From: Allen Ray <allentray125@gmail.com>
Date: Sun, 21 Jun 2020 22:51:08 -0400
Subject: [PATCH] Adding support for clipping rectangles in GLTriangles
---
pixelgl/canvas.go | 3 +++
pixelgl/gltriangles.go | 12 ++++++++++++
2 files changed, 15 insertions(+)
diff --git a/pixelgl/canvas.go b/pixelgl/canvas.go
index 25da939..5bc8437 100644
--- a/pixelgl/canvas.go
+++ b/pixelgl/canvas.go
@@ -327,6 +327,9 @@ func (ct *canvasTriangles) draw(tex *glhf.Texture, bounds pixel.Rect) {
}
ct.vs.Begin()
+ if clip, has := ct.ClipRect(); has {
+ gl.Scissor(int32(clip.Min.X), int32(clip.Min.Y), int32(clip.W()), int32(clip.H()))
+ }
ct.vs.Draw()
ct.vs.End()
diff --git a/pixelgl/gltriangles.go b/pixelgl/gltriangles.go
index f258102..557f420 100644
--- a/pixelgl/gltriangles.go
+++ b/pixelgl/gltriangles.go
@@ -16,6 +16,7 @@ type GLTriangles struct {
vs *glhf.VertexSlice
data []float32
shader *glhf.Shader
+ clip pixel.Rect
}
var (
@@ -213,3 +214,14 @@ func (gt *GLTriangles) Picture(i int) (pic pixel.Vec, intensity float64) {
intensity = float64(gt.data[i*gt.vs.Stride()+8])
return pixel.V(float64(tx), float64(ty)), intensity
}
+
+// SetClipRect sets the rectangle to scissor the triangles by
+func (gt *GLTriangles) SetClipRect(r pixel.Rect) {
+ gt.clip = r.Norm()
+}
+
+// ClipRect gets the clipping rectangle and returns true if that
+// rectangle is not the Zero Rectangle
+func (gt *GLTriangles) ClipRect() (pixel.Rect, bool) {
+ return gt.clip, gt.clip.Area() != 0
+}
--
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