app/headless: add lower-level backend tests

Add a series of low level gpu.Backend tests to assure the correct behaviour of
Backends. The immediate use is debugging of the Direct3D port, in the future
for developing new backends.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

app/headless/backend_test.go

@@ -0,0 +1,247 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package headless
+
+import (
+	"bytes"
+	"flag"
+	"image"
+	"image/color"
+	"image/png"
+	"io/ioutil"
+	"math"
+	"runtime"
+	"testing"
+
+	"gioui.org/gpu/backend"
+	"gioui.org/internal/unsafe"
+)
+
+var dumpImages = flag.Bool("saveimages", false, "save test images")
+
+var clearCol = color.RGBA{A: 0xff, R: 0xde, G: 0xad, B: 0xbe}
+
+func TestFramebufferClear(t *testing.T) {
+	b := newBackend(t)
+	sz := image.Point{X: 800, Y: 600}
+	fbo := setupFBO(t, b, sz)
+	img := screenshot(t, fbo, sz)
+	if got := img.RGBAAt(0, 0); got != clearCol {
+		t.Errorf("got color %v, expected %v", got, clearCol)
+	}
+}
+
+func TestSimpleShader(t *testing.T) {
+	b := newBackend(t)
+	sz := image.Point{X: 800, Y: 600}
+	fbo := setupFBO(t, b, sz)
+	p, err := b.NewProgram(shader_simple_vert, shader_simple_frag)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer p.Release()
+	b.BindProgram(p)
+	b.DrawArrays(backend.DrawModeTriangles, 0, 3)
+	img := screenshot(t, fbo, sz)
+	if got := img.RGBAAt(0, 0); got != clearCol {
+		t.Errorf("got color %v, expected %v", got, clearCol)
+	}
+	// Just off the center to catch inverted triangles.
+	cx, cy := 300, 400
+	shaderCol := [4]float32{.25, .55, .75, 1.0}
+	if got, exp := img.RGBAAt(cx, cy), tosRGB(shaderCol); got != exp {
+		t.Errorf("got color %v, expected %v", got, exp)
+	}
+}
+
+func TestInputShader(t *testing.T) {
+	b := newBackend(t)
+	sz := image.Point{X: 800, Y: 600}
+	fbo := setupFBO(t, b, sz)
+	p, err := b.NewProgram(shader_input_vert, shader_simple_frag)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer p.Release()
+	b.BindProgram(p)
+	buf, err := b.NewImmutableBuffer(backend.BufferBindingVertices,
+		unsafe.BytesView([]float32{
+			0, .5, .5, 1,
+			-.5, -.5, .5, 1,
+			.5, -.5, .5, 1,
+		}),
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer buf.Release()
+	b.BindVertexBuffer(buf, 4*4, 0)
+	layout, err := b.NewInputLayout(shader_input_vert, []backend.InputDesc{
+		{
+			Type:   backend.DataTypeFloat,
+			Size:   4,
+			Offset: 0,
+		},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer layout.Release()
+	b.BindInputLayout(layout)
+	b.DrawArrays(backend.DrawModeTriangles, 0, 3)
+	img := screenshot(t, fbo, sz)
+	if got := img.RGBAAt(0, 0); got != clearCol {
+		t.Errorf("got color %v, expected %v", got, clearCol)
+	}
+	cx, cy := 300, 400
+	shaderCol := [4]float32{.25, .55, .75, 1.0}
+	if got, exp := img.RGBAAt(cx, cy), tosRGB(shaderCol); got != exp {
+		t.Errorf("got color %v, expected %v", got, exp)
+	}
+}
+
+func TestFramebuffers(t *testing.T) {
+	b := newBackend(t)
+	sz := image.Point{X: 800, Y: 600}
+	fbo1 := newFBO(t, b, sz)
+	fbo2 := newFBO(t, b, sz)
+	var (
+		col1 = color.RGBA{R: 0xad, G: 0xbe, B: 0xef, A: 0xde}
+		col2 = color.RGBA{R: 0xfe, G: 0xba, B: 0xbe, A: 0xca}
+	)
+	fcol1, fcol2 := fromsRGB(col1), fromsRGB(col2)
+	b.ClearColor(fcol1[0], fcol1[1], fcol1[2], fcol1[3])
+	b.BindFramebuffer(fbo1)
+	b.Clear(backend.BufferAttachmentColor)
+	b.ClearColor(fcol2[0], fcol2[1], fcol2[2], fcol2[3])
+	b.BindFramebuffer(fbo2)
+	b.Clear(backend.BufferAttachmentColor)
+	img := screenshot(t, fbo1, sz)
+	if got := img.RGBAAt(0, 0); got != col1 {
+		t.Errorf("got color %v, expected %v", got, col1)
+	}
+	img = screenshot(t, fbo2, sz)
+	if got := img.RGBAAt(0, 0); got != col2 {
+		t.Errorf("got color %v, expected %v", got, col2)
+	}
+}
+
+func setupFBO(t *testing.T, b backend.Device, size image.Point) backend.Framebuffer {
+	fbo := newFBO(t, b, size)
+	b.BindFramebuffer(fbo)
+	b.Clear(backend.BufferAttachmentColor | backend.BufferAttachmentDepth)
+	b.Viewport(0, 0, size.X, size.Y)
+	return fbo
+}
+
+func newFBO(t *testing.T, b backend.Device, size image.Point) backend.Framebuffer {
+	fboTex, err := b.NewTexture(
+		backend.TextureFormatSRGB,
+		size.X, size.Y,
+		backend.FilterNearest, backend.FilterNearest,
+		backend.BufferBindingFramebuffer,
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() {
+		fboTex.Release()
+	})
+	const depthBits = 16
+	fbo, err := b.NewFramebuffer(fboTex, depthBits)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() {
+		fbo.Release()
+	})
+	return fbo
+}
+
+func newBackend(t *testing.T) backend.Device {
+	ctx, err := newContext()
+	if err != nil {
+		t.Skipf("no context available: %v", err)
+	}
+	runtime.LockOSThread()
+	if err := ctx.MakeCurrent(); err != nil {
+		t.Fatal(err)
+	}
+	b, err := ctx.Backend()
+	if err != nil {
+		t.Fatal(err)
+	}
+	b.BeginFrame()
+	// ClearColor accepts linear RGBA colors, while 8-bit colors
+	// are in the sRGB color space.
+	col := fromsRGB(clearCol)
+	b.ClearColor(col[0], col[1], col[2], col[3])
+	t.Cleanup(func() {
+		b.EndFrame()
+		ctx.ReleaseCurrent()
+		runtime.UnlockOSThread()
+		ctx.Release()
+	})
+	return b
+}
+
+func screenshot(t *testing.T, fbo backend.Framebuffer, size image.Point) *image.RGBA {
+	img := image.NewRGBA(image.Rectangle{Max: size})
+	err := fbo.ReadPixels(
+		image.Rectangle{
+			Max: image.Point{X: size.X, Y: size.Y},
+		}, img.Pix)
+	if err != nil {
+		t.Fatal(err)
+	}
+	flipImageY(img)
+	if *dumpImages {
+		if err := saveImage(t.Name()+".png", img); err != nil {
+			t.Error(err)
+		}
+	}
+	return img
+}
+
+func saveImage(file string, img image.Image) error {
+	var buf bytes.Buffer
+	if err := png.Encode(&buf, img); err != nil {
+		return err
+	}
+	return ioutil.WriteFile(file, buf.Bytes(), 0666)
+}
+
+func tosRGB(col [4]float32) color.RGBA {
+	for i := 0; i <= 2; i++ {
+		c := col[i]
+		// Use the formula from EXT_sRGB.
+		switch {
+		case c <= 0:
+			c = 0
+		case 0 < c && c < 0.0031308:
+			c = 12.92 * c
+		case 0.0031308 <= c && c < 1:
+			c = 1.055*float32(math.Pow(float64(c), 0.41666)) - 0.055
+		case c >= 1:
+			c = 1
+		}
+		col[i] = c
+	}
+	return color.RGBA{R: uint8(col[0]*255 + .5), G: uint8(col[1]*255 + .5), B: uint8(col[2]*255 + .5), A: uint8(col[3]*255 + .5)}
+}
+
+func fromsRGB(col color.Color) [4]float32 {
+	r, g, b, a := col.RGBA()
+	color := [4]float32{float32(r) / 0xffff, float32(g) / 0xffff, float32(b) / 0xffff, float32(a) / 0xffff}
+	for i := 0; i <= 2; i++ {
+		c := color[i]
+		// Use the formula from EXT_sRGB.
+		if c <= 0.04045 {
+			c = c / 12.92
+		} else {
+			c = float32(math.Pow(float64((c+0.055)/1.055), 2.4))
+		}
+		color[i] = c
+	}
+	return color
+}

app/headless/gen.go

@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package headless
+
+//go:generate go run ../../internal/cmd/convertshaders -package headless

app/headless/headless.go

@@ -127,18 +127,23 @@ func (w *Window) Screenshot() (*image.RGBA, error) {
 	if err != nil {
 		return nil, err
 	}
+	flipImageY(img)
+	return img, nil
+}
+
+func flipImageY(img *image.RGBA) {
 	// Flip image in y-direction. OpenGL's origin is in the lower
 	// left corner.
 	row := make([]uint8, img.Stride)
-	for y := 0; y < w.size.Y/2; y++ {
-		y1 := w.size.Y - y - 1
+	sy := img.Bounds().Dy()
+	for y := 0; y < sy/2; y++ {
+		y1 := sy - y - 1
 		dest := img.PixOffset(0, y1)
 		src := img.PixOffset(0, y)
 		copy(row, img.Pix[dest:])
 		copy(img.Pix[dest:], img.Pix[src:src+len(row)])
 		copy(img.Pix[src:], row)
 	}
-	return img, nil
 }
 
 func contextDo(ctx context, f func() error) error {

app/headless/headless_test.go

@@ -13,14 +13,11 @@ import (
 )
 
 func TestHeadless(t *testing.T) {
-	sz := image.Point{X: 800, Y: 600}
-	w, err := NewWindow(sz.X, sz.Y)
-	if err != nil {
-		t.Skipf("headless windows not supported: %v", err)
-	}
-	defer w.Release()
+	w, release := newTestWindow(t)
+	defer release()
 
-	col := color.RGBA{A: 0xff, R: 0xcc, G: 0xcc}
+	sz := w.size
+	col := color.RGBA{A: 0xff, R: 0xca, G: 0xfe}
 	var ops op.Ops
 	paint.ColorOp{Color: col}.Add(&ops)
 	// Paint only part of the screen to avoid the glClear optimization.
@@ -41,3 +38,15 @@ func TestHeadless(t *testing.T) {
 		t.Errorf("got color %v, expected %v", got, col)
 	}
 }
+
+func newTestWindow(t *testing.T) (*Window, func()) {
+	t.Helper()
+	sz := image.Point{X: 800, Y: 600}
+	w, err := NewWindow(sz.X, sz.Y)
+	if err != nil {
+		t.Skipf("headless windows not supported: %v", err)
+	}
+	return w, func() {
+		w.Release()
+	}
+}

app/headless/shaders.go

@@ -0,0 +1,123 @@
+// Code generated by build.go. DO NOT EDIT.
+
+package headless
+
+import "gioui.org/gpu/backend"
+
+var (
+	shader_input_vert = backend.ShaderSources{
+		Inputs:    []backend.InputLocation{backend.InputLocation{Name: "position", Location: 0, Semantic: "POSITION", SemanticIndex: 0, Type: 0x0, Size: 4}},
+		GLSL100ES: "#version 100\n\nattribute vec4 position;\n\nvoid main()\n{\n    gl_Position = position;\n}\n\n",
+		GLSL300ES: "#version 300 es\n\nlayout(location = 0) in vec4 position;\n\nvoid main()\n{\n    gl_Position = position;\n}\n\n",
+		/*
+		   static float4 gl_Position;
+		   static float4 position;
+
+		   struct SPIRV_Cross_Input
+		   {
+		       float4 position : POSITION;
+		   };
+
+		   struct SPIRV_Cross_Output
+		   {
+		       float4 gl_Position : SV_Position;
+		   };
+
+		   void vert_main()
+		   {
+		       gl_Position = position;
+		   }
+
+		   SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+		   {
+		       position = stage_input.position;
+		       vert_main();
+		       SPIRV_Cross_Output stage_output;
+		       stage_output.gl_Position = gl_Position;
+		       return stage_output;
+		   }
+
+		*/
+		HLSL: []byte(nil),
+	}
+	shader_simple_frag = backend.ShaderSources{
+		GLSL100ES: "#version 100\nprecision mediump float;\nprecision highp int;\n\nvoid main()\n{\n    gl_FragData[0] = vec4(0.25, 0.5, 0.75, 1.0);\n}\n\n",
+		GLSL300ES: "#version 300 es\nprecision mediump float;\nprecision highp int;\n\nlayout(location = 0) out vec4 fragColor;\n\nvoid main()\n{\n    fragColor = vec4(0.25, 0.5, 0.75, 1.0);\n}\n\n",
+		/*
+		   static float4 fragColor;
+
+		   struct SPIRV_Cross_Output
+		   {
+		       float4 fragColor : SV_Target0;
+		   };
+
+		   void frag_main()
+		   {
+		       fragColor = float4(0.25f, 0.5f, 0.75f, 1.0f);
+		   }
+
+		   SPIRV_Cross_Output main()
+		   {
+		       frag_main();
+		       SPIRV_Cross_Output stage_output;
+		       stage_output.fragColor = fragColor;
+		       return stage_output;
+		   }
+
+		*/
+		HLSL: []byte(nil),
+	}
+	shader_simple_vert = backend.ShaderSources{
+		GLSL100ES: "#version 100\n\nvoid main()\n{\n    float x;\n    float y;\n    if (gl_VertexID == 0)\n    {\n        x = 0.0;\n        y = 0.5;\n    }\n    else\n    {\n        if (gl_VertexID == 1)\n        {\n            x = 0.5;\n            y = -0.5;\n        }\n        else\n        {\n            x = -0.5;\n            y = -0.5;\n        }\n    }\n    gl_Position = vec4(x, y, 0.5, 1.0);\n}\n\n",
+		GLSL300ES: "#version 300 es\n\nvoid main()\n{\n    float x;\n    float y;\n    if (gl_VertexID == 0)\n    {\n        x = 0.0;\n        y = 0.5;\n    }\n    else\n    {\n        if (gl_VertexID == 1)\n        {\n            x = 0.5;\n            y = -0.5;\n        }\n        else\n        {\n            x = -0.5;\n            y = -0.5;\n        }\n    }\n    gl_Position = vec4(x, y, 0.5, 1.0);\n}\n\n",
+		/*
+		   static float4 gl_Position;
+		   static int gl_VertexIndex;
+		   struct SPIRV_Cross_Input
+		   {
+		       uint gl_VertexIndex : SV_VertexID;
+		   };
+
+		   struct SPIRV_Cross_Output
+		   {
+		       float4 gl_Position : SV_Position;
+		   };
+
+		   void vert_main()
+		   {
+		       float x;
+		       float y;
+		       if (gl_VertexIndex == 0)
+		       {
+		           x = 0.0f;
+		           y = 0.5f;
+		       }
+		       else
+		       {
+		           if (gl_VertexIndex == 1)
+		           {
+		               x = 0.5f;
+		               y = -0.5f;
+		           }
+		           else
+		           {
+		               x = -0.5f;
+		               y = -0.5f;
+		           }
+		       }
+		       gl_Position = float4(x, y, 0.5f, 1.0f);
+		   }
+
+		   SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+		   {
+		       gl_VertexIndex = int(stage_input.gl_VertexIndex);
+		       vert_main();
+		       SPIRV_Cross_Output stage_output;
+		       stage_output.gl_Position = gl_Position;
+		       return stage_output;
+		   }
+
+		*/
+		HLSL: []byte(nil),
+	}
+)

app/headless/shaders/input.vert

@@ -0,0 +1,11 @@
+#version 310 es
+
+// SPDX-License-Identifier: Unlicense OR MIT
+
+precision highp float;
+
+layout(location=0) in vec4 position;
+
+void main() {
+	gl_Position = position;
+}

app/headless/shaders/simple.frag

@@ -0,0 +1,11 @@
+#version 310 es
+
+// SPDX-License-Identifier: Unlicense OR MIT
+
+precision mediump float;
+
+layout(location = 0) out vec4 fragColor;
+
+void main() {
+	fragColor = vec4(.25, .55, .75, 1.0);
+}

app/headless/shaders/simple.vert

@@ -0,0 +1,20 @@
+#version 310 es
+
+// SPDX-License-Identifier: Unlicense OR MIT
+
+precision highp float;
+
+void main() {
+	float x, y;
+	if (gl_VertexIndex == 0) {
+		x = 0.0;
+		y = .5;
+	} else if (gl_VertexIndex == 1) {
+		x = .5;
+		y = -.5;
+	} else {
+		x = -.5;
+		y = -.5;
+	}
+	gl_Position = vec4(x, y, 0.5, 1.0);
+}