From 0b45ca7057fe859086491f73c21f63222a0a1b98 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Sun, 2 Oct 2022 20:33:43 +0900
Subject: [PATCH] ebiten: reduce duplicated shader compilations

---
 internal/ui/context.go | 10 +++++-----
 internal/ui/image.go   |  4 ++--
 shader.go              | 24 ++++++++++++++++++------
 3 files changed, 25 insertions(+), 13 deletions(-)

diff --git a/internal/ui/context.go b/internal/ui/context.go
index 68b5147d1..b98e5d7f7 100644
--- a/internal/ui/context.go
+++ b/internal/ui/context.go
@@ -67,8 +67,8 @@ func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
 
 var (
 	screenShader        *Shader
-	nearestFilterShader = &Shader{shader: mipmap.NearestFilterShader}
-	linearFilterShader  = &Shader{shader: mipmap.LinearFilterShader}
+	NearestFilterShader = &Shader{shader: mipmap.NearestFilterShader}
+	LinearFilterShader  = &Shader{shader: mipmap.LinearFilterShader}
 )
 
 func init() {
@@ -242,15 +242,15 @@ func (c *context) drawGame(graphicsDriver graphicsdriver.Graphics) {
 	var shader *Shader
 	switch {
 	case !theGlobalState.isScreenFilterEnabled():
-		shader = nearestFilterShader
+		shader = NearestFilterShader
 	case math.Floor(s) == s:
-		shader = nearestFilterShader
+		shader = NearestFilterShader
 	case s > 1:
 		shader = screenShader
 	default:
 		// screenShader works with >=1 scale, but does not well with <1 scale.
 		// Use regular FilterLinear instead so far (#669).
-		shader = linearFilterShader
+		shader = LinearFilterShader
 	}
 
 	dstRegion := graphicsdriver.Region{
diff --git a/internal/ui/image.go b/internal/ui/image.go
index 8d821f378..a6d713b36 100644
--- a/internal/ui/image.go
+++ b/internal/ui/image.go
@@ -196,7 +196,7 @@ func (i *Image) resolveDotsCacheIfNeeded() {
 		Width:  float32(i.width),
 		Height: float32(i.height),
 	}
-	i.mipmap.DrawTriangles(srcs, vs, is, affine.ColorMIdentity{}, graphicsdriver.CompositeModeCopy, graphicsdriver.FilterNearest, graphicsdriver.AddressUnsafe, dr, graphicsdriver.Region{}, [graphics.ShaderImageCount - 1][2]float32{}, nearestFilterShader.shader, nil, false, true)
+	i.mipmap.DrawTriangles(srcs, vs, is, affine.ColorMIdentity{}, graphicsdriver.CompositeModeCopy, graphicsdriver.FilterNearest, graphicsdriver.AddressUnsafe, dr, graphicsdriver.Region{}, [graphics.ShaderImageCount - 1][2]float32{}, NearestFilterShader.shader, nil, false, true)
 }
 
 func DumpImages(dir string) (string, error) {
@@ -236,5 +236,5 @@ func (i *Image) Fill(r, g, b, a float32, x, y, width, height int) {
 
 	srcs := [graphics.ShaderImageCount]*Image{emptyImage}
 
-	i.DrawTriangles(srcs, vs, is, affine.ColorMIdentity{}, graphicsdriver.CompositeModeCopy, graphicsdriver.FilterNearest, graphicsdriver.AddressUnsafe, dstRegion, graphicsdriver.Region{}, [graphics.ShaderImageCount - 1][2]float32{}, nearestFilterShader, nil, false, true)
+	i.DrawTriangles(srcs, vs, is, affine.ColorMIdentity{}, graphicsdriver.CompositeModeCopy, graphicsdriver.FilterNearest, graphicsdriver.AddressUnsafe, dstRegion, graphicsdriver.Region{}, [graphics.ShaderImageCount - 1][2]float32{}, NearestFilterShader, nil, false, true)
 }
diff --git a/shader.go b/shader.go
index 4e7e8f62c..a8dc0e5ab 100644
--- a/shader.go
+++ b/shader.go
@@ -81,11 +81,23 @@ func builtinShader(filter graphicsdriver.Filter, address graphicsdriver.Address,
 		return s
 	}
 
-	src := builtinshader.Shader(filter, address, useColorM)
-	s, err := NewShader(src)
-	if err != nil {
-		panic(fmt.Sprintf("ebiten: NewShader for a built-in shader failed: %v", err))
+	var shader *Shader
+	if address == graphicsdriver.AddressUnsafe && !useColorM {
+		switch filter {
+		case graphicsdriver.FilterNearest:
+			shader = &Shader{shader: ui.NearestFilterShader}
+		case graphicsdriver.FilterLinear:
+			shader = &Shader{shader: ui.LinearFilterShader}
+		}
+	} else {
+		src := builtinshader.Shader(filter, address, useColorM)
+		s, err := NewShader(src)
+		if err != nil {
+			panic(fmt.Sprintf("ebiten: NewShader for a built-in shader failed: %v", err))
+		}
+		shader = s
 	}
-	builtinShaders[key] = s
-	return s
+
+	builtinShaders[key] = shader
+	return shader
 }