ebiten, internal/builtinshader: use an array instead of a map

runtime.mapaccess2 is one of heavy function calls.

Updates #2601

internal/builtinshader/shader.go

@@ -28,6 +28,8 @@ const (
 	FilterLinear
 )
 
+const FilterCount = 2
+
 type Address int
 
 const (
@@ -36,19 +38,15 @@ const (
 	AddressRepeat
 )
 
+const AddressCount = 3
+
 const (
 	UniformColorMBody        = "ColorMBody"
 	UniformColorMTranslation = "ColorMTranslation"
 )
 
-type key struct {
-	Filter    Filter
-	Address   Address
-	UseColorM bool
-}
-
 var (
-	shaders  = map[key][]byte{}
+	shaders  [FilterCount][AddressCount][2][]byte
 	shadersM sync.Mutex
 )
 
@@ -132,12 +130,11 @@ func Shader(filter Filter, address Address, useColorM bool) []byte {
 	shadersM.Lock()
 	defer shadersM.Unlock()
 
-	k := key{
-		Filter:    filter,
-		Address:   address,
-		UseColorM: useColorM,
+	var c int
+	if useColorM {
+		c = 1
 	}
-	if s, ok := shaders[k]; ok {
+	if s := shaders[filter][address][c]; s != nil {
 		return s
 	}
 
@@ -165,6 +162,6 @@ func Shader(filter Filter, address Address, useColorM bool) []byte {
 	}
 
 	b := buf.Bytes()
-	shaders[k] = b
+	shaders[filter][address][c] = b
 	return b
 }

shader.go

@@ -59,14 +59,8 @@ func (s *Shader) appendUniforms(dst []uint32, uniforms map[string]any) []uint32
 	return s.shader.AppendUniforms(dst, uniforms)
 }
 
-type builtinShaderKey struct {
-	filter    builtinshader.Filter
-	address   builtinshader.Address
-	useColorM bool
-}
-
 var (
-	builtinShaders  = map[builtinShaderKey]*Shader{}
+	builtinShaders  [builtinshader.FilterCount][builtinshader.AddressCount][2]*Shader
 	builtinShadersM sync.Mutex
 )
 
@@ -74,12 +68,11 @@ func builtinShader(filter builtinshader.Filter, address builtinshader.Address, u
 	builtinShadersM.Lock()
 	defer builtinShadersM.Unlock()
 
-	key := builtinShaderKey{
-		filter:    filter,
-		address:   address,
-		useColorM: useColorM,
+	var c int
+	if useColorM {
+		c = 1
 	}
-	if s, ok := builtinShaders[key]; ok {
+	if s := builtinShaders[filter][address][c]; s != nil {
 		return s
 	}
 
@@ -100,6 +93,6 @@ func builtinShader(filter builtinshader.Filter, address builtinshader.Address, u
 		shader = s
 	}
 
-	builtinShaders[key] = shader
+	builtinShaders[filter][address][c] = shader
 	return shader
 }