1 /*
   2  * Copyright (c) 2019, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25  
  26 #include <metal_stdlib>
  27 using namespace metal;
  28 
  29 #import "MetalShaderTypes.h"
  30 
  31 
  32 struct VertexOut {
  33     float4 color;
  34     float4 pos [[position]];
  35 };
  36 
  37 
  38 /*
  39     Java2D coordinate system : Top Left (0, 0) : Bottom Right (width and height)
  40     Metal coordinate system is : 
  41     Center is (0.0, 0.0)
  42     Bottom Left (-1.0, -1.0) : Top Right (1.0, 1.0)
  43     Top Left (-1.0, 1.0) : Bottom Right (1.0, -1.0)
  44 */
  45 
  46 vertex VertexOut vertexShader(device MetalVertex *vertices [[buffer(0)]], 
  47                               constant unsigned int *viewportSize [[buffer(1)]],
  48                               uint vid [[vertex_id]]) {
  49     VertexOut out;
  50     out.pos = vertices[vid].position;
  51 
  52     float halfViewWidth = (float)(viewportSize[0] >> 1);
  53     float halfViewHeight = (float)(viewportSize[1] >> 1);
  54 
  55     out.pos.x = (out.pos.x - halfViewWidth) / halfViewWidth;
  56     out.pos.y = (halfViewHeight - out.pos.y) / halfViewHeight;
  57    
  58     out.color = vertices[vid].color;
  59 
  60     return out;
  61 }
  62 
  63 
  64 fragment float4 fragmentShader(MetalVertex in [[stage_in]]) {
  65     return in.color;
  66 }