From f92253487f627aa7d69806a3174b242ee71225a2 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Sat, 30 May 2020 03:21:45 +0900
Subject: [PATCH] buffered: Add Shader

---
 image.go                        |  2 +-
 internal/buffered/image.go      | 38 ++++++++++++++++++++++++++++++---
 internal/buffered/image_test.go |  2 ++
 internal/mipmap/mipmap.go       |  1 +
 4 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/image.go b/image.go
index 4d85878af981..c7336c729dfd 100644
--- a/image.go
+++ b/image.go
@@ -331,7 +331,7 @@ func (i *Image) DrawTriangles(vertices []Vertex, indices []uint16, img *Image, o
 	is := make([]uint16, len(indices))
 	copy(is, indices)
 
-	i.buffered.DrawTriangles(img.buffered, vs, is, options.ColorM.impl, mode, filter, driver.Address(options.Address))
+	i.buffered.DrawTriangles(img.buffered, vs, is, options.ColorM.impl, mode, filter, driver.Address(options.Address), nil, nil)
 }
 
 // SubImage returns an image representing the portion of the image p visible through r. The returned value shares pixels with the original image.
diff --git a/internal/buffered/image.go b/internal/buffered/image.go
index 4832c6e3b98d..c3a39903851d 100644
--- a/internal/buffered/image.go
+++ b/internal/buffered/image.go
@@ -22,6 +22,7 @@ import (
 	"github.com/hajimehoshi/ebiten/internal/affine"
 	"github.com/hajimehoshi/ebiten/internal/driver"
 	"github.com/hajimehoshi/ebiten/internal/mipmap"
+	"github.com/hajimehoshi/ebiten/internal/shaderir"
 )
 
 type Image struct {
@@ -286,7 +287,7 @@ func (i *Image) drawImage(src *Image, bounds image.Rectangle, g mipmap.GeoM, col
 // DrawTriangles draws the src image with the given vertices.
 //
 // Copying vertices and indices is the caller's responsibility.
-func (i *Image) DrawTriangles(src *Image, vertices []float32, indices []uint16, colorm *affine.ColorM, mode driver.CompositeMode, filter driver.Filter, address driver.Address) {
+func (i *Image) DrawTriangles(src *Image, vertices []float32, indices []uint16, colorm *affine.ColorM, mode driver.CompositeMode, filter driver.Filter, address driver.Address, shader *Shader, uniforms []interface{}) {
 	if i == src {
 		panic("buffered: Image.DrawTriangles: src must be different from the receiver")
 	}
@@ -297,7 +298,7 @@ func (i *Image) DrawTriangles(src *Image, vertices []float32, indices []uint16,
 	if needsToDelayCommands {
 		delayedCommands = append(delayedCommands, func() error {
 			// Arguments are not copied. Copying is the caller's responsibility.
-			i.DrawTriangles(src, vertices, indices, colorm, mode, filter, address)
+			i.DrawTriangles(src, vertices, indices, colorm, mode, filter, address, shader, uniforms)
 			return nil
 		})
 		return
@@ -305,5 +306,36 @@ func (i *Image) DrawTriangles(src *Image, vertices []float32, indices []uint16,
 
 	src.resolvePendingPixels(true)
 	i.resolvePendingPixels(false)
-	i.img.DrawTriangles(src.img, vertices, indices, colorm, mode, filter, address, nil, nil)
+
+	var s *mipmap.Shader
+	if shader != nil {
+		s = shader.shader
+	}
+	us := make([]interface{}, len(uniforms))
+	for k, v := range uniforms {
+		switch v := v.(type) {
+		case *Image:
+			i.resolvePendingPixels(true)
+			us[k] = v.img
+		default:
+			us[k] = v
+		}
+	}
+
+	i.img.DrawTriangles(src.img, vertices, indices, colorm, mode, filter, address, s, us)
+}
+
+type Shader struct {
+	shader *mipmap.Shader
+}
+
+func NewShader(program *shaderir.Program) *Shader {
+	return &Shader{
+		shader: mipmap.NewShader(program),
+	}
+}
+
+func (s *Shader) MarkDisposed() {
+	s.shader.MarkDisposed()
+	s.shader = nil
 }
diff --git a/internal/buffered/image_test.go b/internal/buffered/image_test.go
index 58a921fad950..2c1d22d6c00e 100644
--- a/internal/buffered/image_test.go
+++ b/internal/buffered/image_test.go
@@ -306,3 +306,5 @@ func TestReplacePixelsAndModifyBeforeMain(t *testing.T) {
 		t.Errorf("got: %v, want: %v", got, want)
 	}
 }
+
+// TODO: Add tests for shaders and ReplacePixels to check resolvePendingPiexles works correctly.
diff --git a/internal/mipmap/mipmap.go b/internal/mipmap/mipmap.go
index 1ac39799e165..104cda7517f5 100644
--- a/internal/mipmap/mipmap.go
+++ b/internal/mipmap/mipmap.go
@@ -184,6 +184,7 @@ func (m *Mipmap) DrawTriangles(src *Mipmap, vertices []float32, indices []uint16
 			vertices[i*n+11] *= ca
 		}
 	}
+
 	var s *shareable.Shader
 	if shader != nil {
 		s = shader.shader