ebiten: Change the type of Uniforms to map[string]interface{}

Fixes #1324

examples/shader/dissolve.go

@@ -18,7 +18,7 @@ package main
 
 var Time float
 var Cursor vec2
-var ScreenImage vec2
+var ScreenSize vec2
 
 func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
 	// Triangle wave to go 0-->1-->0...

examples/shader/dissolve_go.go

@@ -2,4 +2,4 @@
 
 package main
 
-var dissolve_go = []byte("// Copyright 2020 The Ebiten Authors\n//\n// Licensed under the Apache License, Version 2.0 (the \"License\");\n// you may not use this file except in compliance with the License.\n// You may obtain a copy of the License at\n//\n//     http://www.apache.org/licenses/LICENSE-2.0\n//\n// Unless required by applicable law or agreed to in writing, software\n// distributed under the License is distributed on an \"AS IS\" BASIS,\n// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n// See the License for the specific language governing permissions and\n// limitations under the License.\n\n// +build ignore\n\npackage main\n\nvar Time float\nvar Cursor vec2\nvar ScreenImage vec2\n\nfunc Fragment(position vec4, texCoord vec2, color vec4) vec4 {\n\t// Triangle wave to go 0-->1-->0...\n\tlimit := abs(2*fract(Time/3) - 1)\n\tlevel := imageSrc3At(texCoord).x\n\n\t// Add a white border\n\tif limit-0.1 < level && level < limit {\n\t\talpha := imageSrc0At(texCoord).w\n\t\treturn vec4(alpha)\n\t}\n\n\treturn step(limit, level) * imageSrc0At(texCoord)\n}\n")
+var dissolve_go = []byte("// Copyright 2020 The Ebiten Authors\n//\n// Licensed under the Apache License, Version 2.0 (the \"License\");\n// you may not use this file except in compliance with the License.\n// You may obtain a copy of the License at\n//\n//     http://www.apache.org/licenses/LICENSE-2.0\n//\n// Unless required by applicable law or agreed to in writing, software\n// distributed under the License is distributed on an \"AS IS\" BASIS,\n// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n// See the License for the specific language governing permissions and\n// limitations under the License.\n\n// +build ignore\n\npackage main\n\nvar Time float\nvar Cursor vec2\nvar ScreenSize vec2\n\nfunc Fragment(position vec4, texCoord vec2, color vec4) vec4 {\n\t// Triangle wave to go 0-->1-->0...\n\tlimit := abs(2*fract(Time/3) - 1)\n\tlevel := imageSrc3At(texCoord).x\n\n\t// Add a white border\n\tif limit-0.1 < level && level < limit {\n\t\talpha := imageSrc0At(texCoord).w\n\t\treturn vec4(alpha)\n\t}\n\n\treturn step(limit, level) * imageSrc0At(texCoord)\n}\n")

examples/shader/main.go

@@ -130,10 +130,10 @@ func (g *Game) Draw(screen *ebiten.Image) {
 	cx, cy := ebiten.CursorPosition()
 
 	op := &ebiten.DrawRectShaderOptions{}
-	op.Uniforms = []interface{}{
+	op.Uniforms = map[string]interface{}{
-		float32(g.time) / 60,                // Time
+		"Time":       float32(g.time) / 60,
-		[]float32{float32(cx), float32(cy)}, // Cursor
+		"Cursor":     []float32{float32(cx), float32(cy)},
-		[]float32{float32(w), float32(h)},   // ScreenSize
+		"ScreenSize": []float32{float32(w), float32(h)},
 	}
 	op.Images[0] = gopherImage
 	op.Images[1] = normalImage

image.go

@@ -140,7 +140,7 @@ type DrawImageOptions struct {
 	// Uniforms is a set of uniform variables for the shader.
 	//
 	// Uniforms is used only when Shader is not nil.
-	Uniforms []interface{}
+	Uniforms map[string]interface{}
 
 	// Deprecated: (as of 1.5.0) Use SubImage instead.
 	ImageParts ImageParts
@@ -288,7 +288,8 @@ func (i *Image) DrawImage(img *Image, options *DrawImageOptions) error {
 		return nil
 	}
 
-	i.mipmap.DrawTriangles(srcs, vs, is, nil, mode, filter, driver.AddressUnsafe, sr, options.Shader.shader, options.Uniforms, canSkipMipmap(options.GeoM, filter))
+	us := options.Shader.convertUniforms(options.Uniforms)
+	i.mipmap.DrawTriangles(srcs, vs, is, nil, mode, filter, driver.AddressUnsafe, sr, options.Shader.shader, us, canSkipMipmap(options.GeoM, filter))
 	return nil
 }
 
@@ -358,7 +359,7 @@ type DrawTrianglesOptions struct {
 	// Uniforms is a set of uniform variables for the shader.
 	//
 	// Uniforms is used only when Shader is not nil.
-	Uniforms []interface{}
+	Uniforms map[string]interface{}
 }
 
 // MaxIndicesNum is the maximum number of indices for DrawTriangles.
@@ -454,7 +455,9 @@ func (i *Image) DrawTriangles(vertices []Vertex, indices []uint16, img *Image, o
 		i.mipmap.DrawTriangles(srcs, vs, is, options.ColorM.impl, mode, filter, driver.Address(options.Address), sr, nil, nil, false)
 		return
 	}
-	i.mipmap.DrawTriangles(srcs, vs, is, nil, mode, driver.FilterNearest, driver.AddressUnsafe, sr, options.Shader.shader, options.Uniforms, false)
+
+	us := options.Shader.convertUniforms(options.Uniforms)
+	i.mipmap.DrawTriangles(srcs, vs, is, nil, mode, driver.FilterNearest, driver.AddressUnsafe, sr, options.Shader.shader, us, false)
 }
 
 // DrawRectShaderOptions represents options for DrawRectShader
@@ -470,7 +473,7 @@ type DrawRectShaderOptions struct {
 	CompositeMode CompositeMode
 
 	// Uniforms is a set of uniform variables for the shader.
-	Uniforms []interface{}
+	Uniforms map[string]interface{}
 
 	// Images is a set of the source images.
 	// All the image must be the same size with the rectangle.
@@ -542,7 +545,8 @@ func (i *Image) DrawRectShader(width, height int, shader *Shader, options *DrawR
 		}
 	}
 
-	i.mipmap.DrawTriangles(imgs, vs, is, nil, mode, driver.FilterNearest, driver.AddressUnsafe, sr, shader.shader, options.Uniforms, canSkipMipmap(options.GeoM, driver.FilterNearest))
+	us := shader.convertUniforms(options.Uniforms)
+	i.mipmap.DrawTriangles(imgs, vs, is, nil, mode, driver.FilterNearest, driver.AddressUnsafe, sr, shader.shader, us, canSkipMipmap(options.GeoM, driver.FilterNearest))
 }
 
 // DrawTrianglesShaderOptions represents options for DrawTrianglesShader
@@ -554,7 +558,7 @@ type DrawTrianglesShaderOptions struct {
 	CompositeMode CompositeMode
 
 	// Uniforms is a set of uniform variables for the shader.
-	Uniforms []interface{}
+	Uniforms map[string]interface{}
 
 	// Images is a set of the source images.
 	// All the image must be the same size.
@@ -649,7 +653,8 @@ func (i *Image) DrawTrianglesShader(vertices []Vertex, indices []uint16, shader
 		}
 	}
 
-	i.mipmap.DrawTriangles(imgs, vs, is, nil, mode, driver.FilterNearest, driver.AddressUnsafe, sr, shader.shader, options.Uniforms, false)
+	us := shader.convertUniforms(options.Uniforms)
+	i.mipmap.DrawTriangles(imgs, vs, is, nil, mode, driver.FilterNearest, driver.AddressUnsafe, sr, shader.shader, us, false)
 }
 
 // SubImage returns an image representing the portion of the image p visible through r.

shader.go

@@ -19,6 +19,7 @@ import (
 	"fmt"
 	"go/parser"
 	"go/token"
+	"strings"
 
 	"github.com/hajimehoshi/ebiten/internal/graphics"
 	"github.com/hajimehoshi/ebiten/internal/mipmap"
@@ -102,7 +103,8 @@ func __vertex(position vec2, texCoord vec2, color vec4) (vec4, vec2, vec4) {
 }
 
 type Shader struct {
-	shader *mipmap.Shader
+	shader       *mipmap.Shader
+	uniformNames []string
 }
 
 func NewShader(src []byte) (*Shader, error) {
@@ -133,7 +135,8 @@ func NewShader(src []byte) (*Shader, error) {
 	}
 
 	return &Shader{
-		shader: mipmap.NewShader(s),
+		shader:       mipmap.NewShader(s),
+		uniformNames: s.UniformNames,
 	}, nil
 }
 
@@ -141,3 +144,28 @@ func (s *Shader) Dispose() {
 	s.shader.MarkDisposed()
 	s.shader = nil
 }
+
+func (s *Shader) convertUniforms(uniforms map[string]interface{}) []interface{} {
+	names := map[string]int{}
+	var idx int
+	for _, n := range s.uniformNames {
+		if strings.HasPrefix(n, "__") {
+			continue
+		}
+		names[n] = idx
+		idx++
+	}
+
+	us := make([]interface{}, len(names))
+	for n, u := range uniforms {
+		idx, ok := names[n]
+		if !ok {
+			// TODO: Panic here?
+			continue
+		}
+		us[idx] = u
+	}
+
+	// TODO: Check the uniform variable types?
+	return us
+}