From 8a6302f9dc4d2b8f6649e04105d5c0a18b5f8623 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Sat, 14 Aug 2021 20:05:26 +0900
Subject: [PATCH] internal/atlas: Add tests to call DrawTriangles twice

Updates #1755
---
 internal/atlas/shader_test.go | 90 +++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 internal/atlas/shader_test.go

diff --git a/internal/atlas/shader_test.go b/internal/atlas/shader_test.go
new file mode 100644
index 000000000..b4f7cebb5
--- /dev/null
+++ b/internal/atlas/shader_test.go
@@ -0,0 +1,90 @@
+// Copyright 2021 The Ebiten Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package atlas_test
+
+import (
+	"image/color"
+	"testing"
+
+	"github.com/hajimehoshi/ebiten/v2/internal/affine"
+	. "github.com/hajimehoshi/ebiten/v2/internal/atlas"
+	"github.com/hajimehoshi/ebiten/v2/internal/driver"
+	"github.com/hajimehoshi/ebiten/v2/internal/graphics"
+	etesting "github.com/hajimehoshi/ebiten/v2/internal/testing"
+)
+
+func TestShaderFillTwice(t *testing.T) {
+	const w, h = 1, 1
+
+	dst := NewImage(w, h)
+
+	vs := quadVertices(w, h, 0, 0, 1)
+	is := graphics.QuadIndices()
+	dr := driver.Region{
+		X:      0,
+		Y:      0,
+		Width:  w,
+		Height: h,
+	}
+	p0 := etesting.ShaderProgramFill(0xff, 0xff, 0xff, 0xff)
+	s0 := NewShader(&p0)
+	dst.DrawTriangles([graphics.ShaderImageNum]*Image{}, vs, is, affine.ColorMIdentity{}, driver.CompositeModeCopy, driver.FilterNearest, driver.AddressUnsafe, dr, driver.Region{}, [graphics.ShaderImageNum - 1][2]float32{}, s0, nil, false)
+
+	// Vertices must be recreated (#1755)
+	vs = quadVertices(w, h, 0, 0, 1)
+	p1 := etesting.ShaderProgramFill(0x80, 0x80, 0x80, 0xff)
+	s1 := NewShader(&p1)
+	dst.DrawTriangles([graphics.ShaderImageNum]*Image{}, vs, is, affine.ColorMIdentity{}, driver.CompositeModeCopy, driver.FilterNearest, driver.AddressUnsafe, dr, driver.Region{}, [graphics.ShaderImageNum - 1][2]float32{}, s1, nil, false)
+
+	pix, err := dst.Pixels(0, 0, w, h)
+	if err != nil {
+		t.Error(err)
+	}
+	if got, want := (color.RGBA{pix[0], pix[1], pix[2], pix[3]}), (color.RGBA{0x80, 0x80, 0x80, 0xff}); got != want {
+		t.Errorf("got: %v, want: %v", got, want)
+	}
+}
+
+func TestImageDrawTwice(t *testing.T) {
+	const w, h = 1, 1
+
+	dst := NewImage(w, h)
+	src0 := NewImage(w, h)
+	src0.ReplacePixels([]byte{0xff, 0xff, 0xff, 0xff})
+	src1 := NewImage(w, h)
+	src1.ReplacePixels([]byte{0x80, 0x80, 0x80, 0xff})
+
+	vs := quadVertices(w, h, 0, 0, 1)
+	is := graphics.QuadIndices()
+	dr := driver.Region{
+		X:      0,
+		Y:      0,
+		Width:  w,
+		Height: h,
+	}
+	dst.DrawTriangles([graphics.ShaderImageNum]*Image{src0}, vs, is, affine.ColorMIdentity{}, driver.CompositeModeCopy, driver.FilterNearest, driver.AddressUnsafe, dr, driver.Region{}, [graphics.ShaderImageNum - 1][2]float32{}, nil, nil, false)
+
+	// Vertices must be recreated (#1755)
+	vs = quadVertices(w, h, 0, 0, 1)
+	dst.DrawTriangles([graphics.ShaderImageNum]*Image{src1}, vs, is, affine.ColorMIdentity{}, driver.CompositeModeCopy, driver.FilterNearest, driver.AddressUnsafe, dr, driver.Region{}, [graphics.ShaderImageNum - 1][2]float32{}, nil, nil, false)
+
+	pix, err := dst.Pixels(0, 0, w, h)
+	if err != nil {
+		t.Error(err)
+	}
+	if got, want := (color.RGBA{pix[0], pix[1], pix[2], pix[3]}), (color.RGBA{0x80, 0x80, 0x80, 0xff}); got != want {
+		t.Errorf("got: %v, want: %v", got, want)
+	}
+}