<@include gpu/Config.slh@>
<$VERSION_HEADER$>
//  Generated on <$_SCRIBE_DATE$>
//
//  drawWorkloadProxy.vert
//  vertex shader
//
//  Created by Sam Gateau on 6/29/2015.
//  Copyright 2015 High Fidelity, Inc.
//  Copyright 2024 Overte e.V.
//
//  Distributed under the Apache License, Version 2.0.
//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
//

<@include gpu/Transform.slh@>
<$declareStandardTransform()$>

<@include WorkloadResource.slh@>
<$declareWorkloadProxies()$>


layout(location=0) out vec4 varColor;
layout(location=1) out vec3 varTexcoord;
layout(location=2) out vec3 varEyePos;
layout(location=3) out vec4 _prevPositionCS;

vec4 getPosition(WorkloadProxy proxy, vec4 spriteVert, vec4 proxyPosEye) {
    vec3 dirZ = -normalize(proxyPosEye.xyz);
    vec3 dirX = normalize(cross(vec3(0.0, 1.0, 0.0), dirZ));
    vec3 dirY = vec3(0.0, 1.0, 0.0);
    // Workaround for Nvidia driver bug
    vec4 pos = vec4(1.0, 1.0, 1.0, 1.0);
    pos.x = proxyPosEye.x + proxy.sphere.w * ( dirX.x * spriteVert.x + dirY.x * spriteVert.y + dirZ.x * spriteVert.z);
    pos.y = proxyPosEye.y + proxy.sphere.w * ( dirX.y * spriteVert.x + dirY.y * spriteVert.y + dirZ.y * spriteVert.z);
    pos.z = proxyPosEye.z + proxy.sphere.w * ( dirX.z * spriteVert.x + dirY.z * spriteVert.y + dirZ.z * spriteVert.z);
    return pos;
    //return vec4(proxyPosEye.xyz + proxy.sphere.w * (dirX * spriteVert.x + dirY * spriteVert.y /* + dirZ * spriteVert.z*/), 1.0);
}

void main(void) {
    const vec4 UNIT_SPRITE[3] = vec4[3](
        vec4(-1.0, -1.0, 0.0, 1.0),
        vec4(3.0, -1.0, 0.0, 1.0),
        vec4(-1.0, 3.0, 0.0, 1.0)
    );
     const int UNIT_SPRITE_INDICES[3] = int[3](
        0, 1, 2
    );
    int proxyID = gl_VertexID / 3;
    int vertexID = gl_VertexID - proxyID * 3;

    vec4 spriteVert = UNIT_SPRITE[UNIT_SPRITE_INDICES[vertexID]];

    WorkloadProxy proxy = getWorkloadProxy(proxyID);
    vec4 proxyPosWorld = vec4(proxy.sphere.xyz, 1.0);

    // standard transform, bring proxy in view space
    TransformCamera cam = getTransformCamera();
    TransformObject obj = getTransformObject();
    vec4 proxyPosEye;
    vec4 prevProxyPosEye;
    <$transformModelToEyePosAndPrevEyePos(cam, obj, proxyPosWorld, proxyPosEye, prevProxyPosEye)$>

    // Define the billboarded space
    vec4 pos = getPosition(proxy, spriteVert, proxyPosEye);
    vec4 prevPos = getPosition(proxy, spriteVert, prevProxyPosEye);

    varEyePos = pos.xyz;
    varTexcoord = spriteVert.xyz;
    <$transformEyeToClipPos(cam, pos, gl_Position)$>
    <$transformPrevEyeToPrevClipPos(cam, prevPos, _prevPositionCS)$>;

    // Convert region to color
    int region = floatBitsToInt(proxy.region.x);
    region = (0x000000FF & region);

    varColor = vec4(REGION_COLOR[region].xyz, proxy.sphere.w);

    gl_Position = mix(gl_Position, vec4(0.0), float(region == 4));
}