From b9d131409e6b7ead0e6a7b4e57bf4ce98edcea99 Mon Sep 17 00:00:00 2001
From: Elias Naur <mail@eliasnaur.com>
Date: Sun, 23 Feb 2020 14:43:03 +0100
Subject: [PATCH] gpu/gl: tolerate programs with no attributes

Signed-off-by: Elias Naur <mail@eliasnaur.com>
---
 gpu/gl/backend.go | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/gpu/gl/backend.go b/gpu/gl/backend.go
index 87f120cc..5b0de58d 100644
--- a/gpu/gl/backend.go
+++ b/gpu/gl/backend.go
@@ -348,7 +348,11 @@ func (b *Backend) DrawArrays(mode backend.DrawMode, off, count int) {
 }
 
 func (b *Backend) prepareDraw() {
-	b.setupVertexArrays()
+	nattr := b.state.prog.nattr
+	b.enableVertexArrays(nattr)
+	if nattr > 0 {
+		b.setupVertexArrays()
+	}
 	if p := b.state.prog; p != nil {
 		p.updateUniforms()
 	}
@@ -469,7 +473,6 @@ func (p *gpuProgram) updateUniforms() {
 func (b *Backend) BindProgram(prog backend.Program) {
 	p := prog.(*gpuProgram)
 	b.useProgram(p)
-	b.enableVertexArrays(p.nattr)
 }
 
 func (p *gpuProgram) Release() {