-- glslfx version 0.1

//
// Copyright 2018 Pixar
//
// Licensed under the Apache License, Version 2.0 (the "Apache License")
// with the following modification; you may not use this file except in
// compliance with the Apache License and the following modification to it:
// Section 6. Trademarks. is deleted and replaced with:
//
// 6. Trademarks. This License does not grant permission to use the trade
//    names, trademarks, service marks, or product names of the Licensor
//    and its affiliates, except as required to comply with Section 4(c) of
//    the License and to reproduce the content of the NOTICE file.
//
// You may obtain a copy of the Apache License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the Apache License with the above modification is
// distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the Apache License for the specific
// language governing permissions and limitations under the Apache License.
//

-- configuration
{
    "techniques": {
        "default": {
            "FullscreenVertex": {
                "source": [ "Fullscreen.Vertex" ]
            },
            "CompositeFragmentNoDepth": {
                "source": [ "Composite.FragmentNoDepth" ]
            },
            "CompositeFragmentWithDepth": {
                "source": [ "Composite.FragmentWithDepth" ]
            }
        },
        "Metal": {
            "FullscreenVertex": {
                "source": [
                    "Fullscreen.Metal.Common",
                    "Fullscreen.Metal.Vertex"
                ]
            },
            "CompositeFragmentNoDepth": {
                "source": [
                    "Fullscreen.Metal.Common",
                    "Composite.Metal.FragmentNoDepth"
                ]
            },
            "CompositeFragmentWithDepth": {
                "source": [
                    "Fullscreen.Metal.Common",
                    "Composite.Metal.FragmentWithDepth"
                ]
            }
        }

    }
}

-- glsl Fullscreen.Vertex

#version 450

layout(location = 0) in vec4 position;
layout(location = 1) in  vec2 uvIn;

layout(location = 0) out vec2 uv;

void main(void)
{
    gl_Position = position;
    uv = uvIn;
}

-- glsl Composite.FragmentNoDepth

#version 450

layout(location = 0) in vec2 uv;

layout (binding = 0) uniform sampler2D color;

void main(void)
{
    gl_FragColor = texture(color, uv);
}

-- glsl Composite.FragmentWithDepth

#version 450

layout(location = 0) in vec2 uv;

layout (binding = 0) uniform sampler2D color;
layout (binding = 1) uniform sampler2D depth;

void main(void)
{
    float depth = texture(depth, uv).r;
    gl_FragColor = texture(color, uv);
    gl_FragDepth = depth;
}

-- glsl Fullscreen.Metal.Common

struct Interpolated {
    float4 position [[position]];
    float2 uv;
};

-- glsl Fullscreen.Metal.Vertex

struct Vertex {
    float4 position [[attribute(0)]];
    float2 uvIn [[attribute(1)]];
};

vertex Interpolated vertexEntryPoint(Vertex v [[stage_in]])
{
    Interpolated out;
    out.position = v.position;
    out.uv = v.uvIn;
    return out;
}

-- glsl Composite.Metal.FragmentNoDepth

constexpr sampler texSampler(address::clamp_to_edge);

fragment half4 fragmentEntryPoint(
    Interpolated input[[stage_in]],
    texture2d<float> color[[texture(0)]])
{
    return color.sample(texSampler, input.uv);
}

-- glsl Composite.Metal.FragmentWithDepth

struct Out {
    float4 color [[color(0)]];
    float depth [[depth(any)]];
};

constexpr sampler texSampler(address::clamp_to_edge);

fragment Out fragmentEntryPoint(
    Interpolated input[[stage_in]],
    texture2d<float> color[[texture(0)]],
    depth2d<float> depth[[texture(1)]])
{
    Out out;
    out.depth = depth.sample(texSampler, input.uv);
    out.color = color.sample(texSampler, input.uv);
    return out;
}