From 37baaee464a700d1f04fa32d8b74530c1570d502 Mon Sep 17 00:00:00 2001
From: faiface <faiface@ksp.sk>
Date: Fri, 20 Jan 2017 18:40:48 +0100
Subject: [PATCH] add forgotten gltriangles.go
---
gltriangles.go | 141 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 141 insertions(+)
create mode 100644 gltriangles.go
diff --git a/gltriangles.go b/gltriangles.go
new file mode 100644
index 0000000..7d985fd
--- /dev/null
+++ b/gltriangles.go
@@ -0,0 +1,141 @@
+package pixel
+
+import (
+ "github.com/faiface/mainthread"
+ "github.com/faiface/pixel/pixelgl"
+)
+
+// NewGLTriangles returns OpenGL triangles implemented using pixelgl.VertexSlice. A few notes.
+//
+// Triangles returned from this function support TrianglesPosition, TrianglesColor and
+// TrianglesTexture. If you need to support more, you can "override" Update and Append method.
+//
+// Draw method simply draws the underlying pixelgl.VertexSlice. It needs to be called in the main
+// thread manually. Also, you need to take care of additional Target initialization or setting of
+// uniform attributes.
+func NewGLTriangles(shader *pixelgl.Shader, t Triangles) Triangles {
+ var gt *glTriangles
+ mainthread.Call(func() {
+ gt = &glTriangles{
+ vs: pixelgl.MakeVertexSlice(shader, 0, t.Len()),
+ shader: shader,
+ }
+ })
+ gt.Update(t)
+ return gt
+}
+
+type glTriangles struct {
+ vs *pixelgl.VertexSlice
+ data []float32
+ shader *pixelgl.Shader
+}
+
+func (gt *glTriangles) Len() int {
+ return len(gt.data) / gt.vs.Stride()
+}
+
+func (gt *glTriangles) Draw() {
+ gt.vs.Begin()
+ gt.vs.Draw()
+ gt.vs.End()
+}
+
+func (gt *glTriangles) resize(len int) {
+ if len > gt.Len() {
+ needAppend := len - gt.Len()
+ for i := 0; i < needAppend; i++ {
+ gt.data = append(gt.data,
+ 0, 0,
+ 1, 1, 1, 1,
+ -1, -1,
+ )
+ }
+ }
+ if len < gt.Len() {
+ gt.data = gt.data[:len]
+ }
+}
+
+func (gt *glTriangles) updateData(offset int, t Triangles) {
+ if t, ok := t.(TrianglesPosition); ok {
+ for i := offset; i < offset+t.Len(); i++ {
+ px, py := t.Position(i).XY()
+ gt.data[i*gt.vs.Stride()+0] = float32(px)
+ gt.data[i*gt.vs.Stride()+1] = float32(py)
+ }
+ }
+ if t, ok := t.(TrianglesColor); ok {
+ for i := offset; i < offset+t.Len(); i++ {
+ col := t.Color(i)
+ gt.data[i*gt.vs.Stride()+2] = float32(col.R)
+ gt.data[i*gt.vs.Stride()+3] = float32(col.G)
+ gt.data[i*gt.vs.Stride()+4] = float32(col.B)
+ gt.data[i*gt.vs.Stride()+5] = float32(col.A)
+ }
+ }
+ if t, ok := t.(TrianglesTexture); ok {
+ for i := offset; i < offset+t.Len(); i++ {
+ tx, ty := t.Texture(i).XY()
+ gt.data[i*gt.vs.Stride()+6] = float32(tx)
+ gt.data[i*gt.vs.Stride()+7] = float32(ty)
+ }
+ }
+}
+
+func (gt *glTriangles) submitData() {
+ data := gt.data // avoid race condition
+ mainthread.CallNonBlock(func() {
+ gt.vs.Begin()
+ dataLen := len(data) / gt.vs.Stride()
+ if dataLen > gt.vs.Len() {
+ gt.vs.Append(make([]float32, (dataLen-gt.vs.Len())*gt.vs.Stride()))
+ }
+ if dataLen < gt.vs.Len() {
+ gt.vs = gt.vs.Slice(0, dataLen)
+ }
+ gt.vs.SetVertexData(gt.data)
+ gt.vs.End()
+ })
+}
+
+func (gt *glTriangles) Update(t Triangles) {
+ gt.resize(t.Len())
+ gt.updateData(0, t)
+ gt.submitData()
+}
+
+func (gt *glTriangles) Append(t Triangles) {
+ gt.resize(gt.Len() + t.Len())
+ gt.updateData(gt.Len()-t.Len(), t)
+ gt.submitData()
+}
+
+func (gt *glTriangles) Copy() Triangles {
+ return NewGLTriangles(gt.shader, gt)
+}
+
+func (gt *glTriangles) Position(i int) Vec {
+ px := gt.data[i*gt.vs.Stride()+0]
+ py := gt.data[i*gt.vs.Stride()+1]
+ return V(float64(px), float64(py))
+}
+
+func (gt *glTriangles) Color(i int) NRGBA {
+ r := gt.data[i*gt.vs.Stride()+2]
+ g := gt.data[i*gt.vs.Stride()+3]
+ b := gt.data[i*gt.vs.Stride()+4]
+ a := gt.data[i*gt.vs.Stride()+5]
+ return NRGBA{
+ R: float64(r),
+ G: float64(g),
+ B: float64(b),
+ A: float64(a),
+ }
+}
+
+func (gt *glTriangles) Texture(i int) Vec {
+ tx := gt.data[i*gt.vs.Stride()+6]
+ ty := gt.data[i*gt.vs.Stride()+7]
+ return V(float64(tx), float64(ty))
+}
--
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