diff --git a/internal/graphicsdriver/directx/graphics11_windows.go b/internal/graphicsdriver/directx/graphics11_windows.go
index 53035b2f6..e77b0cfe0 100644
--- a/internal/graphicsdriver/directx/graphics11_windows.go
+++ b/internal/graphicsdriver/directx/graphics11_windows.go
@@ -24,6 +24,7 @@ import (
 	"github.com/hajimehoshi/ebiten/v2/internal/graphics"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
 	"github.com/hajimehoshi/ebiten/v2/internal/shaderir"
+	"github.com/hajimehoshi/ebiten/v2/internal/shaderir/hlsl"
 )
 
 var inputElementDescsForDX11 = []_D3D11_INPUT_ELEMENT_DESC{
@@ -481,7 +482,7 @@ func (g *graphics11) MaxImageSize() int {
 }
 
 func (g *graphics11) NewShader(program *shaderir.Program) (graphicsdriver.Shader, error) {
-	vsh, psh, offsets, err := compileShader(program)
+	vsh, psh, err := compileShader(program)
 	if err != nil {
 		return nil, err
 	}
@@ -490,7 +491,7 @@ func (g *graphics11) NewShader(program *shaderir.Program) (graphicsdriver.Shader
 		graphics:         g,
 		id:               g.genNextShaderID(),
 		uniformTypes:     program.Uniforms,
-		uniformOffsets:   offsets,
+		uniformOffsets:   hlsl.CalcUniformMemoryOffsets(program),
 		vertexShaderBlob: vsh,
 		pixelShaderBlob:  psh,
 	}
diff --git a/internal/graphicsdriver/directx/graphics12_windows.go b/internal/graphicsdriver/directx/graphics12_windows.go
index dae2f9c7f..634b5c06d 100644
--- a/internal/graphicsdriver/directx/graphics12_windows.go
+++ b/internal/graphicsdriver/directx/graphics12_windows.go
@@ -25,6 +25,7 @@ import (
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
 	"github.com/hajimehoshi/ebiten/v2/internal/microsoftgdk"
 	"github.com/hajimehoshi/ebiten/v2/internal/shaderir"
+	"github.com/hajimehoshi/ebiten/v2/internal/shaderir/hlsl"
 )
 
 type resourceWithSize struct {
@@ -1063,7 +1064,7 @@ func (g *graphics12) MaxImageSize() int {
 }
 
 func (g *graphics12) NewShader(program *shaderir.Program) (graphicsdriver.Shader, error) {
-	vsh, psh, offsets, err := compileShader(program)
+	vsh, psh, err := compileShader(program)
 	if err != nil {
 		return nil, err
 	}
@@ -1072,7 +1073,7 @@ func (g *graphics12) NewShader(program *shaderir.Program) (graphicsdriver.Shader
 		graphics:       g,
 		id:             g.genNextShaderID(),
 		uniformTypes:   program.Uniforms,
-		uniformOffsets: offsets,
+		uniformOffsets: hlsl.CalcUniformMemoryOffsets(program),
 		vertexShader:   vsh,
 		pixelShader:    psh,
 	}
diff --git a/internal/graphicsdriver/directx/shader_windows.go b/internal/graphicsdriver/directx/shader_windows.go
index cd197e28e..a8003b7a2 100644
--- a/internal/graphicsdriver/directx/shader_windows.go
+++ b/internal/graphicsdriver/directx/shader_windows.go
@@ -26,8 +26,8 @@ import (
 
 var vertexShaderCache = map[string]*_ID3DBlob{}
 
-func compileShader(program *shaderir.Program) (vsh, psh *_ID3DBlob, uniformOffsets []int, ferr error) {
-	vs, ps, offsets := hlsl.Compile(program)
+func compileShader(program *shaderir.Program) (vsh, psh *_ID3DBlob, ferr error) {
+	vs, ps := hlsl.Compile(program)
 	var flag uint32 = uint32(_D3DCOMPILE_OPTIMIZATION_LEVEL3)
 
 	defer func() {
@@ -76,10 +76,10 @@ func compileShader(program *shaderir.Program) (vsh, psh *_ID3DBlob, uniformOffse
 	})
 
 	if err := wg.Wait(); err != nil {
-		return nil, nil, nil, err
+		return nil, nil, err
 	}
 
-	return vsh, psh, offsets, nil
+	return vsh, psh, nil
 }
 
 func constantBufferSize(uniformTypes []shaderir.Type, uniformOffsets []int) int {
diff --git a/internal/shader/shader_test.go b/internal/shader/shader_test.go
index fd4abaee1..954ba099d 100644
--- a/internal/shader/shader_test.go
+++ b/internal/shader/shader_test.go
@@ -188,7 +188,7 @@ func TestCompile(t *testing.T) {
 			}
 
 			if tc.HLSL != nil {
-				vs, _, _ := hlsl.Compile(s)
+				vs, _ := hlsl.Compile(s)
 				if got, want := hlslNormalize(vs), hlslNormalize(string(tc.HLSL)); got != want {
 					compare(t, "HLSL", got, want)
 				}
diff --git a/internal/shaderir/hlsl/hlsl.go b/internal/shaderir/hlsl/hlsl.go
index ca43cad45..22a05e635 100644
--- a/internal/shaderir/hlsl/hlsl.go
+++ b/internal/shaderir/hlsl/hlsl.go
@@ -86,8 +86,8 @@ float4x4 float4x4FromScalar(float x) {
 	return float4x4(x, 0, 0, 0, 0, x, 0, 0, 0, 0, x, 0, 0, 0, 0, x);
 }`
 
-func Compile(p *shaderir.Program) (vertexShader, pixelShader string, offsets []int) {
-	offsets = calculateMemoryOffsets(p.Uniforms)
+func Compile(p *shaderir.Program) (vertexShader, pixelShader string) {
+	offsets := CalcUniformMemoryOffsets(p)
 
 	c := &compileContext{
 		unit: p.Unit,
diff --git a/internal/shaderir/hlsl/packing.go b/internal/shaderir/hlsl/packing.go
index ee28d01ee..217a12576 100644
--- a/internal/shaderir/hlsl/packing.go
+++ b/internal/shaderir/hlsl/packing.go
@@ -22,7 +22,7 @@ import (
 
 const boundaryInBytes = 16
 
-func calculateMemoryOffsets(uniforms []shaderir.Type) []int {
+func CalcUniformMemoryOffsets(program *shaderir.Program) []int {
 	// https://docs.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-packing-rules
 	// https://github.com/microsoft/DirectXShaderCompiler/wiki/Buffer-Packing
 
@@ -38,7 +38,7 @@ func calculateMemoryOffsets(uniforms []shaderir.Type) []int {
 
 	// TODO: Reorder the variables with packoffset.
 	// See https://docs.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-variable-packoffset
-	for _, u := range uniforms {
+	for _, u := range program.Uniforms {
 		switch u.Main {
 		case shaderir.Float:
 			offsets = append(offsets, head)