shader: Add 'if'

Updates #1230

internal/shader/expr.go

@@ -297,6 +297,14 @@ func (cs *compileState) parseExpr(block *block, expr ast.Expr) ([]shaderir.Expr,
 		return exprs, f.ir.OutParams, stmts, true
 
 	case *ast.Ident:
+		if e.Name == "true" || e.Name == "false" {
+			return []shaderir.Expr{
+				{
+					Type:  shaderir.NumberExpr,
+					Const: gconstant.MakeBool(e.Name == "true"),
+				},
+			}, []shaderir.Type{{Main: shaderir.Bool}}, nil, true
+		}
 		if i, t, ok := block.findLocalVariable(e.Name); ok {
 			return []shaderir.Expr{
 				{

internal/shader/shader.go

@@ -582,7 +582,7 @@ func (cs *compileState) parseFunc(block *block, d *ast.FuncDecl) (function, bool
 		}
 	}
 
-	b, ok := cs.parseBlock(block, d.Body, inParams, outParams)
+	b, ok := cs.parseBlock(block, d.Body.List, inParams, outParams)
 	if !ok {
 		return function{}, false
 	}
@@ -606,7 +606,7 @@ func (cs *compileState) parseFunc(block *block, d *ast.FuncDecl) (function, bool
 	}, true
 }
 
-func (cs *compileState) parseBlock(outer *block, b *ast.BlockStmt, inParams, outParams []variable) (*block, bool) {
+func (cs *compileState) parseBlock(outer *block, stmts []ast.Stmt, inParams, outParams []variable) (*block, bool) {
 	vars := make([]variable, 0, len(inParams)+len(outParams))
 	vars = append(vars, inParams...)
 	vars = append(vars, outParams...)
@@ -620,12 +620,12 @@ func (cs *compileState) parseBlock(outer *block, b *ast.BlockStmt, inParams, out
 		}
 	}()
 
-	for _, l := range b.List {
-		stmts, ok := cs.parseStmt(block, l, inParams)
+	for _, stmt := range stmts {
+		ss, ok := cs.parseStmt(block, stmt, inParams)
 		if !ok {
 			return nil, false
 		}
-		block.ir.Stmts = append(block.ir.Stmts, stmts...)
+		block.ir.Stmts = append(block.ir.Stmts, ss...)
 	}
 
 	return block, true

internal/shader/stmt.go

@@ -95,7 +95,7 @@ func (cs *compileState) parseStmt(block *block, stmt ast.Stmt, inParams []variab
 			cs.addError(stmt.Pos(), fmt.Sprintf("unexpected token: %s", stmt.Tok))
 		}
 	case *ast.BlockStmt:
-		b, ok := cs.parseBlock(block, stmt, nil, nil)
+		b, ok := cs.parseBlock(block, stmt.List, nil, nil)
 		if !ok {
 			return nil, false
 		}
@@ -109,6 +109,48 @@ func (cs *compileState) parseStmt(block *block, stmt ast.Stmt, inParams []variab
 		if !cs.parseDecl(block, stmt.Decl) {
 			return nil, false
 		}
+	case *ast.IfStmt:
+		// TODO: Parse stmt.Init
+
+		exprs, ts, ss, ok := cs.parseExpr(block, stmt.Cond)
+		if !ok {
+			return nil, false
+		}
+		if len(ts) != 1 || ts[0].Main != shaderir.Bool {
+			cs.addError(stmt.Pos(), fmt.Sprintf("if-condition must be bool but: %#v", ts))
+			return nil, false
+		}
+		stmts = append(stmts, ss...)
+
+		var bs []shaderir.Block
+		b, ok := cs.parseBlock(block, stmt.Body.List, nil, nil)
+		if !ok {
+			return nil, false
+		}
+		bs = append(bs, b.ir)
+
+		if stmt.Else != nil {
+			switch s := stmt.Else.(type) {
+			case *ast.BlockStmt:
+				b, ok := cs.parseBlock(block, s.List, nil, nil)
+				if !ok {
+					return nil, false
+				}
+				bs = append(bs, b.ir)
+			default:
+				b, ok := cs.parseBlock(block, []ast.Stmt{s}, nil, nil)
+				if !ok {
+					return nil, false
+				}
+				bs = append(bs, b.ir)
+			}
+		}
+
+		stmts = append(stmts, shaderir.Stmt{
+			Type:   shaderir.If,
+			Exprs:  exprs,
+			Blocks: bs,
+		})
 	case *ast.ReturnStmt:
 		for i, r := range stmt.Results {
 			exprs, _, ss, ok := cs.parseExpr(block, r)

internal/shader/testdata/if.expected.vs

@@ -0,0 +1,10 @@
+void F0(out vec2 l0) {
+	bool l1 = false;
+	l1 = true;
+	if (l1) {
+		l0 = vec2(0.0);
+		return;
+	}
+	l0 = vec2(1.0);
+	return;
+}

internal/shader/testdata/if.go

@@ -0,0 +1,9 @@
+package main
+
+func Foo() vec2 {
+	x := true
+	if x {
+		return vec2(0)
+	}
+	return vec2(1)
+}

internal/shader/testdata/if_else.expected.vs

@@ -0,0 +1,11 @@
+void F0(out vec2 l0) {
+	bool l1 = false;
+	l1 = true;
+	if (l1) {
+		l0 = vec2(0.0);
+		return;
+	} else {
+		l0 = vec2(1.0);
+		return;
+	}
+}

internal/shader/testdata/if_else.go

@@ -0,0 +1,10 @@
+package main
+
+func Foo() vec2 {
+	x := true
+	if x {
+		return vec2(0)
+	} else {
+		return vec2(1)
+	}
+}

internal/shaderir/glsl.go

@@ -237,7 +237,15 @@ func (p *Program) glslBlock(b *Block, level int, localVarIndex int) []string {
 		switch e.Type {
 		case NumberExpr:
 			switch e.ConstType {
-			case ConstTypeNone, ConstTypeFloat:
+			case ConstTypeNone:
+				if e.Const.Kind() == constant.Bool {
+					if constant.BoolVal(e.Const) {
+						return "true"
+					}
+					return "false"
+				}
+				fallthrough
+			case ConstTypeFloat:
 				if i := constant.ToInt(e.Const); i.Kind() == constant.Int {
 					x, _ := constant.Int64Val(i)
 					return fmt.Sprintf("%d.0", x)