GLES100.ts

import { BaseToken } from "../common/BaseToken";
import { ASTNode } from "../parser/AST";
import { GLESVisitor } from "./GLESVisitor";
import { VisitorContext } from "./VisitorContext";
import { ICodeSegment } from "./types";

export class GLES100Visitor extends GLESVisitor {
  override _versionText: string = `#version 100`;
  override _extensions: string = [
    "GL_EXT_shader_texture_lod",
    "GL_OES_standard_derivatives",
    "GL_EXT_draw_buffers",
    "GL_EXT_frag_depth"
  ]
    .map((e) => `#extension ${e} : enable\n`)
    .join("");

  private static _singleton: GLES100Visitor;
  static getVisitor(): GLES100Visitor {
    if (!this._singleton) {
      this._singleton = new GLES100Visitor();
    }
    return this._singleton;
  }

  override getFragDataCodeGen(index: string | number): string {
    return `gl_FragData[${index}]`;
  }

  override getReferencedMRTPropText(index: string | number, ident: string): string {
    return "";
  }

  override getAttributeDeclare(out: ICodeSegment[]): void {
    for (const item of Object.values(VisitorContext.context._referencedAttributeList)) {
      out.push({
        text: `attribute ${item.typeInfo.typeLexeme} ${item.ident.lexeme};`,
        index: item.ident.location.start.index
      });
    }
  }

  override getVaryingDeclare(out: ICodeSegment[]): void {
    for (const item of Object.values(VisitorContext.context._referencedVaryingList)) {
      out.push({
        text: `varying ${item.typeInfo.typeLexeme} ${item.ident.lexeme};`,
        index: item.ident.location.start.index
      });
    }
  }

  override getMRTDeclare(out: ICodeSegment[]): void {
    return;
  }

  override visitPostfixExpression(node: ASTNode.PostfixExpression): string {
    const { children } = node;
    const postExpr = children[0];
    const { context } = VisitorContext;
    if (postExpr instanceof ASTNode.PostfixExpression && context.isMRTStruct(<string>postExpr.type)) {
      const propReferenced = children[2] as BaseToken;
      const prop = context.mrtStruct!.propList.find((item) => item.ident.lexeme === propReferenced.lexeme);
      if (!prop) {
        this._reportError(propReferenced.location, `not found mrt property: ${propReferenced.lexeme}`);
        return "";
      }
      return `gl_FragData[${prop.mrtIndex!}]`;
    }
    return super.visitPostfixExpression(node);
  }

  override visitJumpStatement(node: ASTNode.JumpStatement): string {
    if (node.isFragReturnStatement) {
      const expression = node.children[1] as ASTNode.Expression;
      return `gl_FragColor = ${expression.codeGen(this)}`;
    }
    return super.visitJumpStatement(node);
  }
}