gpu: setup OpenGL ES texture uniforms automatically from shader metadata

Signed-off-by: Elias Naur <mail@eliasnaur.com>

gpu/backend.go

@@ -46,6 +46,12 @@ type ShaderSources struct {
 	Uniforms    []UniformLocation
 	UniformSize int
 	Inputs      []InputLocation
+	Textures    []TextureBinding
+}
+
+type TextureBinding struct {
+	Name    string
+	Binding int
 }
 
 type UniformLocation struct {
@@ -109,12 +115,8 @@ type Program interface {
 	Release()
 	SetVertexUniforms(buf Buffer)
 	SetFragmentUniforms(buf Buffer)
-	UniformFor(uniform string) Uniform
-	Uniform1i(u Uniform, v int)
 }
 
-type Uniform interface{}
-
 type Buffer interface {
 	BindVertex(stride, offset int)
 	BindIndex()

gpu/build.go

@@ -27,6 +27,12 @@ type shaderArgs struct {
 	Header         string
 }
 
+// TextureBinding matches gpu.TextureBinding.
+type TextureBinding struct {
+	Name    string
+	Binding int
+}
+
 // InputLocation matches gpu.InputLocation.
 type InputLocation struct {
 	Name          string
@@ -90,6 +96,7 @@ func generate() error {
 			hlsl        []byte
 			inputs      []InputLocation
 			uniforms    []UniformLocation
+			textures    []TextureBinding
 			uniformSize int
 		}
 		args := [nvariants]shaderArgs{
@@ -109,7 +116,7 @@ func generate() error {
 			}
 			// Make the GL ES 2 source compatible with desktop GL 3.
 			gles2 = "#version 100\n" + gles2
-			inputs, uniforms, uniformSize, err := parseReflection(reflect)
+			inputs, uniforms, textures, uniformSize, err := parseReflection(reflect)
 			if err != nil {
 				return err
 			}
@@ -138,6 +145,7 @@ func generate() error {
 			variants[i].hlsl = hlslc
 			variants[i].inputs = inputs
 			variants[i].uniforms = uniforms
+			variants[i].textures = textures
 			variants[i].uniformSize = uniformSize
 		}
 		name := filepath.Base(shader)
@@ -165,8 +173,17 @@ func generate() error {
 					fmt.Fprintf(&out, "{Name: %q, Type: %d, Size: %d, Offset: %d},\n", u.Name, u.Type, u.Size, u.Offset)
 				}
 				fmt.Fprintf(&out, "},\n")
+			}
+			if src.uniformSize != 0 {
 				fmt.Fprintf(&out, "UniformSize: %d,\n", src.uniformSize)
 			}
+			if len(src.textures) > 0 {
+				fmt.Fprintf(&out, "Textures: []TextureBinding{\n")
+				for _, t := range src.textures {
+					fmt.Fprintf(&out, "{Name: %q, Binding: %d},\n", t.Name, t.Binding)
+				}
+				fmt.Fprintf(&out, "},\n")
+			}
 			fmt.Fprintf(&out, "GLES2: %#v,\n", src.gles2)
 			fmt.Fprintf(&out, "/*\n%s\n*/\n", src.hlslSrc)
 			fmt.Fprintf(&out, "HLSL: %#v,\n", src.hlsl)
@@ -191,7 +208,7 @@ func generate() error {
 	return ioutil.WriteFile("shaders.go", gosrc, 0644)
 }
 
-func parseReflection(jsonData []byte) ([]InputLocation, []UniformLocation, int, error) {
+func parseReflection(jsonData []byte) ([]InputLocation, []UniformLocation, []TextureBinding, int, error) {
 	type InputReflection struct {
 		ID            int    `json:"id"`
 		Name          string `json:"name"`
@@ -214,9 +231,18 @@ func parseReflection(jsonData []byte) ([]InputLocation, []UniformLocation, int,
 		Size    int                       `json:"block_size"`
 		Members []UniformMemberReflection `json:"members"`
 	}
+	type TextureReflection struct {
+		ID        int    `json:"id"`
+		Name      string `json:"name"`
+		Set       int    `json:"set"`
+		Binding   int    `json:"binding"`
+		Dimension string `json:"dimension"`
+		Format    string `json:"format"`
+	}
 	type shaderReflection struct {
 		Inputs         []InputReflection         `json:"inputs"`
 		UniformBuffers []UniformBufferReflection `json:"uniform_buffers"`
+		Textures       []TextureReflection       `json:"textures"`
 	}
 	type shaderMetadata struct {
 		VS shaderReflection `json:"vs"`
@@ -224,14 +250,14 @@ func parseReflection(jsonData []byte) ([]InputLocation, []UniformLocation, int,
 	}
 	var reflect shaderMetadata
 	if err := json.Unmarshal(jsonData, &reflect); err != nil {
-		return nil, nil, 0, fmt.Errorf("parseReflection: %v", err)
+		return nil, nil, nil, 0, fmt.Errorf("parseReflection: %v", err)
 	}
 	var inputs []InputLocation
 	inputRef := reflect.VS.Inputs
 	for _, input := range inputRef {
 		dataType, dataSize, err := parseDataType(input.Type)
 		if err != nil {
-			return nil, nil, 0, fmt.Errorf("parseReflection: %v", err)
+			return nil, nil, nil, 0, fmt.Errorf("parseReflection: %v", err)
 		}
 		inputs = append(inputs, InputLocation{
 			Name:          input.Name,
@@ -255,7 +281,7 @@ func parseReflection(jsonData []byte) ([]InputLocation, []UniformLocation, int,
 		for _, member := range block.Members {
 			dataType, size, err := parseDataType(member.Type)
 			if err != nil {
-				return nil, nil, 0, fmt.Errorf("parseReflection: %v", err)
+				return nil, nil, nil, 0, fmt.Errorf("parseReflection: %v", err)
 			}
 			ublocks = append(ublocks, UniformLocation{
 				// Synthetic name generated by glslcc.
@@ -267,7 +293,18 @@ func parseReflection(jsonData []byte) ([]InputLocation, []UniformLocation, int,
 		}
 		blockOffset += block.Size
 	}
-	return inputs, ublocks, blockOffset, nil
+	textures := reflect.VS.Textures
+	if len(textures) == 0 {
+		textures = reflect.FS.Textures
+	}
+	var texBinds []TextureBinding
+	for _, texture := range textures {
+		texBinds = append(texBinds, TextureBinding{
+			Name:    texture.Name,
+			Binding: texture.Binding,
+		})
+	}
+	return inputs, ublocks, texBinds, blockOffset, nil
 }
 
 func parseDataType(t string) (DataType, int, error) {

gpu/gl/backend.go

@@ -366,6 +366,20 @@ func (b *Backend) NewProgram(vssrc, fssrc gpu.ShaderSources) (gpu.Program, error
 		obj:     p,
 		nattr:   len(attr),
 	}
+	gpuProg.Bind()
+	// Bind texture uniforms.
+	for _, tex := range vssrc.Textures {
+		u := b.funcs.GetUniformLocation(p, tex.Name)
+		if u.valid() {
+			b.funcs.Uniform1i(u, tex.Binding)
+		}
+	}
+	for _, tex := range fssrc.Textures {
+		u := b.funcs.GetUniformLocation(p, tex.Name)
+		if u.valid() {
+			b.funcs.Uniform1i(u, tex.Binding)
+		}
+	}
 	gpuProg.vertUniforms.setup(b.funcs, p, vssrc.UniformSize, vssrc.Uniforms)
 	gpuProg.fragUniforms.setup(b.funcs, p, fssrc.UniformSize, fssrc.Uniforms)
 	return gpuProg, nil
@@ -389,21 +403,11 @@ func (p *gpuProgram) updateUniforms() {
 	p.fragUniforms.update(p.backend.funcs)
 }
 
-func (p *gpuProgram) Uniform1i(u gpu.Uniform, v int) {
-	p.Bind()
-	p.backend.funcs.Uniform1i(u.(Uniform), v)
-}
-
 func (p *gpuProgram) Bind() {
 	p.backend.useProgram(p)
 	p.backend.enableVertexArrays(p.nattr)
 }
 
-func (p *gpuProgram) UniformFor(uniform string) gpu.Uniform {
-	f := p.backend.funcs
-	return GetUniformLocation(f, p.obj, uniform)
-}
-
 func (p *gpuProgram) Release() {
 	p.backend.funcs.DeleteProgram(p.obj)
 }

gpu/gpu.go

@@ -425,8 +425,6 @@ func newBlitter(ctx Backend) *blitter {
 	}
 	b.prog = prog
 	b.layout = layout
-	texProg := b.prog[materialTexture].prog
-	texProg.Uniform1i(texProg.UniformFor("tex"), 0)
 	return b
 }
 

gpu/path.go

@@ -134,11 +134,6 @@ func newCoverer(ctx Backend) *coverer {
 	}
 	c.prog = prog
 	c.layout = layout
-	texProg := prog[materialTexture].prog
-	texProg.Uniform1i(texProg.UniformFor("tex"), 0)
-	for _, p := range prog {
-		p.prog.Uniform1i(p.prog.UniformFor("cover"), 1)
-	}
 	return c
 }
 
@@ -190,8 +185,6 @@ func newStenciler(ctx Backend) *stenciler {
 		panic(err)
 	}
 	vertUniforms = newUniformBuffer(ctx, &st.iprog.uniforms.vert)
-	coverLoc := iprog.UniformFor("cover")
-	iprog.Uniform1i(coverLoc, 0)
 	st.iprog.prog = newProgram(iprog, vertUniforms, nil)
 	st.iprog.layout = iprogLayout
 	return st

gpu/shaders.go

@@ -48,6 +48,9 @@ var (
 			HLSL: []byte(nil),
 		},
 		ShaderSources{
+			Textures: []TextureBinding{
+				{Name: "tex", Binding: 0},
+			},
 			GLES2: "#version 100\nprecision mediump float;\nprecision highp int;\n\nuniform mediump sampler2D tex;\n\nvarying vec2 vUV;\n\nvoid main()\n{\n    gl_FragData[0] = texture2D(tex, vUV);\n}\n\n",
 			/*
 			   Texture2D<float4> tex : register(t0);
@@ -155,7 +158,10 @@ var (
 				{Name: "_12._color", Type: 0, Size: 4, Offset: 0},
 			},
 			UniformSize: 16,
-			GLES2:       "#version 100\nprecision mediump float;\nprecision highp int;\n\nstruct Color\n{\n    vec4 _color;\n};\n\nuniform Color _12;\n\nuniform mediump sampler2D cover;\n\nvarying highp vec2 vCoverUV;\nvarying vec2 vUV;\n\nvoid main()\n{\n    gl_FragData[0] = _12._color;\n    float cover_1 = abs(texture2D(cover, vCoverUV).x);\n    gl_FragData[0] *= cover_1;\n}\n\n",
+			Textures: []TextureBinding{
+				{Name: "cover", Binding: 1},
+			},
+			GLES2: "#version 100\nprecision mediump float;\nprecision highp int;\n\nstruct Color\n{\n    vec4 _color;\n};\n\nuniform Color _12;\n\nuniform mediump sampler2D cover;\n\nvarying highp vec2 vCoverUV;\nvarying vec2 vUV;\n\nvoid main()\n{\n    gl_FragData[0] = _12._color;\n    float cover_1 = abs(texture2D(cover, vCoverUV).x);\n    gl_FragData[0] *= cover_1;\n}\n\n",
 			/*
 			   cbuffer Color : register(b0)
 			   {
@@ -201,6 +207,10 @@ var (
 			HLSL: []byte(nil),
 		},
 		ShaderSources{
+			Textures: []TextureBinding{
+				{Name: "tex", Binding: 0},
+				{Name: "cover", Binding: 1},
+			},
 			GLES2: "#version 100\nprecision mediump float;\nprecision highp int;\n\nuniform mediump sampler2D tex;\nuniform mediump sampler2D cover;\n\nvarying vec2 vUV;\nvarying highp vec2 vCoverUV;\n\nvoid main()\n{\n    gl_FragData[0] = texture2D(tex, vUV);\n    float cover_1 = abs(texture2D(cover, vCoverUV).x);\n    gl_FragData[0] *= cover_1;\n}\n\n",
 			/*
 			   Texture2D<float4> tex : register(t0);
@@ -315,6 +325,9 @@ var (
 		HLSL: []byte(nil),
 	}
 	shader_intersect_frag = ShaderSources{
+		Textures: []TextureBinding{
+			{Name: "cover", Binding: 0},
+		},
 		GLES2: "#version 100\nprecision mediump float;\nprecision highp int;\n\nuniform mediump sampler2D cover;\n\nvarying highp vec2 vUV;\n\nvoid main()\n{\n    float cover_1 = abs(texture2D(cover, vUV).x);\n    gl_FragData[0].x = cover_1;\n}\n\n",
 		/*
 		   Texture2D<float4> cover : register(t0);