shader: Analyze blocks and shadowings

internal/shader/shader.go

@@ -28,7 +28,7 @@ import (
 type variable struct {
 	name string
 	typ  typ
-	init ast.Expr
+	init shaderir.Expr
 }
 
 type constant struct {
@@ -68,6 +68,22 @@ type block struct {
 	ir shaderir.Block
 }
 
+func (b *block) findLocalVariable(name string) (int, bool) {
+	idx := 0
+	for outer := b.outer; outer != nil; outer = outer.outer {
+		idx += len(outer.vars)
+	}
+	for i, v := range b.vars {
+		if v.name == name {
+			return idx + i, true
+		}
+	}
+	if b.outer != nil {
+		return b.outer.findLocalVariable(name)
+	}
+	return 0, false
+}
+
 type ParseError struct {
 	errs []string
 }
@@ -106,7 +122,7 @@ func (s *compileState) addError(pos token.Pos, str string) {
 
 func (cs *compileState) parse(f *ast.File) {
 	for _, d := range f.Decls {
-		cs.parseDecl(&cs.global, d, true)
+		cs.parseDecl(&cs.global, d)
 	}
 
 	if len(cs.errs) > 0 {
@@ -118,7 +134,7 @@ func (cs *compileState) parse(f *ast.File) {
 	}
 }
 
-func (cs *compileState) parseDecl(b *block, d ast.Decl, global bool) {
+func (cs *compileState) parseDecl(b *block, d ast.Decl) {
 	switch d := d.(type) {
 	case *ast.GenDecl:
 		switch d.Tok {
@@ -140,18 +156,21 @@ func (cs *compileState) parseDecl(b *block, d ast.Decl, global bool) {
 			for _, s := range d.Specs {
 				s := s.(*ast.ValueSpec)
 				vs := cs.parseVariable(b, s)
-				if !global {
+				if b == &cs.global {
-					b.vars = append(b.vars, vs...)
-					continue
-				}
 					for i, v := range vs {
 						if v.name[0] < 'A' || 'Z' < v.name[0] {
 							cs.addError(s.Names[i].Pos(), fmt.Sprintf("global variables must be exposed: %s", v.name))
 						}
-					// TODO: Check RHS
+						// TODO: Check init
 						cs.uniforms = append(cs.uniforms, v.name)
 						cs.ir.Uniforms = append(cs.ir.Uniforms, v.typ.ir)
 					}
+					continue
+				}
+				for _, v := range vs {
+					b.vars = append(b.vars, v)
+					b.ir.LocalVars = append(b.ir.LocalVars, v.typ.ir)
+				}
 			}
 		case token.IMPORT:
 			cs.addError(d.Pos(), "import is forbidden")
@@ -181,10 +200,14 @@ func (s *compileState) parseVariable(block *block, vs *ast.ValueSpec) []variable
 			}
 		}
 		name := n.Name
+		var e shaderir.Expr
+		if init != nil {
+			e = s.parseExpr(block, init)
+		}
 		vars = append(vars, variable{
 			name: name,
 			typ:  t,
-			init: init,
+			init: e,
 		})
 	}
 	return vars
@@ -298,20 +321,26 @@ func (cs *compileState) parseBlock(outer *block, b *ast.BlockStmt, inParams, out
 				}
 			case token.ASSIGN:
 				// TODO: What about the statement `a,b = b,a?`
-				for range l.Rhs {
+				for i := range l.Rhs {
-					/*block.stmts = append(block.stmts, stmt{
+					block.ir.Stmts = append(block.ir.Stmts, shaderir.Stmt{
-						stmtType: stmtAssign,
+						Type: shaderir.Assign,
-						exprs:    []ast.Expr{l.Lhs[i], l.Rhs[i]},
+						Exprs: []shaderir.Expr{
-					})*/
+							cs.parseExpr(block, l.Lhs[i]),
+							cs.parseExpr(block, l.Rhs[i]),
+						},
+					})
 				}
 			}
 		case *ast.BlockStmt:
-			/*block.stmts = append(block.stmts, stmt{
+			b := cs.parseBlock(block, l, nil, nil)
-				stmtType: stmtBlock,
+			block.ir.Stmts = append(block.ir.Stmts, shaderir.Stmt{
-				block:    cs.parseBlock(block, l),
+				Type: shaderir.BlockStmt,
-			})*/
+				Blocks: []shaderir.Block{
+					b.ir,
+				},
+			})
 		case *ast.DeclStmt:
-			cs.parseDecl(block, l.Decl, false)
+			cs.parseDecl(block, l.Decl)
 		case *ast.ReturnStmt:
 			for i, r := range l.Results {
 				e := cs.parseExpr(block, r)
@@ -379,18 +408,6 @@ func (s *compileState) detectType(b *block, expr ast.Expr) typ {
 	}
 }
 
-func (b *block) findLocalVariable(name string) (int, bool) {
-	for i, v := range b.vars {
-		if v.name == name {
-			return i, true
-		}
-	}
-	if b.outer != nil {
-		return b.outer.findLocalVariable(name)
-	}
-	return 0, false
-}
-
 func (cs *compileState) parseExpr(block *block, expr ast.Expr) shaderir.Expr {
 	switch e := expr.(type) {
 	case *ast.BasicLit:

internal/shader/shader_test.go

@@ -36,8 +36,6 @@ var (
 	Boo vec4
 )`,
 			VS: `uniform vec2 U0;
-uniform vec4 U1;`,
-			FS: `uniform vec2 U0;
 uniform vec4 U1;`,
 		},
 		{
@@ -47,8 +45,6 @@ uniform vec4 U1;`,
 func Foo(foo vec2) vec4 {
 }`,
 			VS: `void F0(in vec2 l0, out vec4 l1) {
-}`,
-			FS: `void F0(in vec2 l0, out vec4 l1) {
 }`,
 		},
 		{
@@ -61,10 +57,6 @@ func Foo(foo vec2) vec4 {
 			VS: `void F0(in vec2 l0, out vec4 l1) {
 	l1 = vec4(l0, 0, 1);
 	return;
-}`,
-			FS: `void F0(in vec2 l0, out vec4 l1) {
-	l1 = vec4(l0, 0, 1);
-	return;
 }`,
 		},
 		{
@@ -81,11 +73,36 @@ func Foo(foo vec4) (float, float, float, float) {
 	l4 = (l0).w;
 	return;
 }`,
-			FS: `void F0(in vec4 l0, out float l1, out float l2, out float l3, out float l4) {
+		},
-	l1 = (l0).x;
+		{
-	l2 = (l0).y;
+			Name: "blocks",
-	l3 = (l0).z;
+			Src: `package main
-	l4 = (l0).w;
+
+func Foo(foo vec2) vec4 {
+	var r vec4
+	{
+		r.x = foo.x
+		var foo vec3
+		{
+			r.y = foo.y
+			var foo vec4
+			r.z = foo.z
+		}
+	}
+	return r
+}`,
+			VS: `void F0(in vec2 l0, out vec4 l1) {
+	vec4 l2 = vec4(0.0);
+	{
+		vec3 l3 = vec3(0.0);
+		(l2).x = (l0).x;
+		{
+			vec4 l4 = vec4(0.0);
+			(l2).y = (l3).y;
+			(l2).z = (l4).z;
+		}
+	}
+	l1 = l2;
 	return;
 }`,
 		},
@@ -100,8 +117,10 @@ func Foo(foo vec4) (float, float, float, float) {
 		if got, want := vs, tc.VS+"\n"; got != want {
 			t.Errorf("%s: got: %v, want: %v", tc.Name, got, want)
 		}
+		if tc.FS != "" {
 			if got, want := fs, tc.FS+"\n"; got != want {
 				t.Errorf("%s: got: %v, want: %v", tc.Name, got, want)
 			}
 		}
+	}
 }

internal/shaderir/glsl.go

@@ -162,6 +162,37 @@ func (p *Program) glslVarDecl(t *Type, varname string) string {
 	}
 }
 
+func (p *Program) glslVarInit(t *Type) string {
+	switch t.Main {
+	case None:
+		return "?(none)"
+	case Array:
+		panic("not implemented")
+	case Struct:
+		panic("not implemented")
+	case Bool:
+		return "false"
+	case Int:
+		return "0"
+	case Float:
+		return "0.0"
+	case Vec2:
+		return "vec2(0.0)"
+	case Vec3:
+		return "vec3(0.0)"
+	case Vec4:
+		return "vec4(0.0)"
+	case Mat2:
+		return "mat2(0.0)"
+	case Mat3:
+		return "mat3(0.0)"
+	case Mat4:
+		return "mat4(0.0)"
+	default:
+		panic(fmt.Sprintf("?(unexpected type: %s)", p.glslType(t)))
+	}
+}
+
 func (p *Program) glslFunc(f *Func) []string {
 	var args []string
 	var idx int
@@ -195,7 +226,7 @@ func (p *Program) glslBlock(b *Block, level int, localVarIndex int) []string {
 
 	var lines []string
 	for _, t := range b.LocalVars {
-		lines = append(lines, fmt.Sprintf("%s%s;", idt, p.glslVarDecl(&t, fmt.Sprintf("l%d", localVarIndex))))
+		lines = append(lines, fmt.Sprintf("%s%s = %s;", idt, p.glslVarDecl(&t, fmt.Sprintf("l%d", localVarIndex)), p.glslVarInit(&t)))
 		localVarIndex++
 	}
 

internal/shaderir/ir_test.go

@@ -296,12 +296,12 @@ varying vec3 V0;`,
 				},
 			},
 			GlslVS: `void F0(in float l0, inout float l1, out float l2) {
-	mat4 l3;
+	mat4 l3 = mat4(0.0);
-	mat4 l4;
+	mat4 l4 = mat4(0.0);
 }`,
 			GlslFS: `void F0(in float l0, inout float l1, out float l2) {
-	mat4 l3;
+	mat4 l3 = mat4(0.0);
-	mat4 l4;
+	mat4 l4 = mat4(0.0);
 }`,
 		},
 		{
@@ -337,19 +337,19 @@ varying vec3 V0;`,
 				},
 			},
 			GlslVS: `void F0(in float l0, inout float l1, out float l2) {
-	mat4 l3;
+	mat4 l3 = mat4(0.0);
-	mat4 l4;
+	mat4 l4 = mat4(0.0);
 	{
-		mat4 l5;
+		mat4 l5 = mat4(0.0);
-		mat4 l6;
+		mat4 l6 = mat4(0.0);
 	}
 }`,
 			GlslFS: `void F0(in float l0, inout float l1, out float l2) {
-	mat4 l3;
+	mat4 l3 = mat4(0.0);
-	mat4 l4;
+	mat4 l4 = mat4(0.0);
 	{
-		mat4 l5;
+		mat4 l5 = mat4(0.0);
-		mat4 l6;
+		mat4 l6 = mat4(0.0);
 	}
 }`,
 		},
@@ -747,9 +747,9 @@ varying float V0;
 varying vec2 V1;
 
 void main(void) {
-	vec2 l0;
+	vec2 l0 = vec2(0.0);
-	vec4 l1;
+	vec4 l1 = vec4(0.0);
-	float l2;
+	float l2 = 0.0;
 	l1 = V0;
 	gl_FragColor = V1;
 	l0 = gl_FragCoord;