From 6453e552f3a1287aa5f348324915fdcedb167261 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Fri, 6 Sep 2024 15:27:50 +0900
Subject: [PATCH] Revert "internal/restorable: remove unnecessary functions and
 variables around shaders"

This reverts commit 4f3e00ec3af857522828312a27d4a5705d21877a.

Updates #3083
---
 internal/atlas/image.go       |  2 +-
 internal/atlas/shader.go      | 10 ++--------
 internal/restorable/images.go | 14 ++++++++++++--
 internal/restorable/shader.go | 23 ++++++++++++++++-------
 4 files changed, 31 insertions(+), 18 deletions(-)

diff --git a/internal/atlas/image.go b/internal/atlas/image.go
index d1eea954d..46e6fbf34 100644
--- a/internal/atlas/image.go
+++ b/internal/atlas/image.go
@@ -408,7 +408,7 @@ func (i *Image) drawTriangles(srcs [graphics.ShaderSrcImageCount]*Image, vertice
 			vertices[i+2] += oxf
 			vertices[i+3] += oyf
 		}
-		if shader.ir.Unit == shaderir.Texels {
+		if shader.ensureShader().Unit() == shaderir.Texels {
 			sw, sh := srcs[0].backend.restorable.InternalSize()
 			swf, shf := float32(sw), float32(sh)
 			for i := 0; i < n; i += graphics.VertexFloatCount {
diff --git a/internal/atlas/shader.go b/internal/atlas/shader.go
index 40dfbf615..f2ff046ed 100644
--- a/internal/atlas/shader.go
+++ b/internal/atlas/shader.go
@@ -75,12 +75,6 @@ func (s *Shader) deallocate() {
 }
 
 var (
-	NearestFilterShader = &Shader{
-		shader: restorable.NearestFilterShader,
-		ir:     restorable.LinearFilterShaderIR,
-	}
-	LinearFilterShader = &Shader{
-		shader: restorable.LinearFilterShader,
-		ir:     restorable.LinearFilterShaderIR,
-	}
+	NearestFilterShader = &Shader{shader: restorable.NearestFilterShader}
+	LinearFilterShader  = &Shader{shader: restorable.LinearFilterShader}
 )
diff --git a/internal/restorable/images.go b/internal/restorable/images.go
index 0adb14746..a1d84d0e2 100644
--- a/internal/restorable/images.go
+++ b/internal/restorable/images.go
@@ -22,12 +22,14 @@ import (
 
 // images is a set of Image objects.
 type images struct {
-	images map[*Image]struct{}
+	images  map[*Image]struct{}
+	shaders map[*Shader]struct{}
 }
 
 // theImages represents the images for the current process.
 var theImages = &images{
-	images: map[*Image]struct{}{},
+	images:  map[*Image]struct{}{},
+	shaders: map[*Shader]struct{}{},
 }
 
 func SwapBuffers(graphicsDriver graphicsdriver.Graphics) error {
@@ -62,11 +64,19 @@ func (i *images) add(img *Image) {
 	i.images[img] = struct{}{}
 }
 
+func (i *images) addShader(shader *Shader) {
+	i.shaders[shader] = struct{}{}
+}
+
 // remove removes img from the images.
 func (i *images) remove(img *Image) {
 	delete(i.images, img)
 }
 
+func (i *images) removeShader(shader *Shader) {
+	delete(i.shaders, shader)
+}
+
 var graphicsDriverInitialized bool
 
 // InitializeGraphicsDriverState initializes the graphics driver state.
diff --git a/internal/restorable/shader.go b/internal/restorable/shader.go
index 9715f5d72..acf94504e 100644
--- a/internal/restorable/shader.go
+++ b/internal/restorable/shader.go
@@ -27,26 +27,37 @@ import (
 
 type Shader struct {
 	shader *graphicscommand.Shader
+	ir     *shaderir.Program
 }
 
 func NewShader(ir *shaderir.Program) *Shader {
 	s := &Shader{
 		shader: graphicscommand.NewShader(ir),
+		ir:     ir,
 	}
+	theImages.addShader(s)
 	return s
 }
 
 func (s *Shader) Dispose() {
+	theImages.removeShader(s)
 	s.shader.Dispose()
 	s.shader = nil
+	s.ir = nil
+}
+
+func (s *Shader) restore() {
+	s.shader = graphicscommand.NewShader(s.ir)
+}
+
+func (s *Shader) Unit() shaderir.Unit {
+	return s.ir.Unit
 }
 
 var (
-	NearestFilterShader   *Shader
-	NearestFilterShaderIR *shaderir.Program
-	LinearFilterShader    *Shader
-	LinearFilterShaderIR  *shaderir.Program
-	clearShader           *Shader
+	NearestFilterShader *Shader
+	LinearFilterShader  *Shader
+	clearShader         *Shader
 )
 
 func init() {
@@ -79,9 +90,7 @@ func init() {
 	if err := wg.Wait(); err != nil {
 		panic(err)
 	}
-	NearestFilterShaderIR = nearestIR
 	NearestFilterShader = NewShader(nearestIR)
-	LinearFilterShaderIR = linearIR
 	LinearFilterShader = NewShader(linearIR)
 	clearShader = NewShader(clearIR)
 }