<!
//  DeferredTransform.slh
//  libraries/render-utils/src
//
//  Created by Sam Gateau on 6/2/16.
//  Copyright 2016 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
!>
<@if not DEFERRED_TRANSFORM_SLH@>
<@def DEFERRED_TRANSFORM_SLH@>

<@include gpu/ShaderConstants.h@>
<@include render-utils/ShaderConstants.h@>

<@func declareDeferredFrameTransform()@>

<@include DeferredTransform_shared.slh@>

#define DeferredFrameTransform _DeferredFrameTransform
#define TransformCamera _TransformCamera

LAYOUT_STD140(binding=RENDER_UTILS_BUFFER_DEFERRED_FRAME_TRANSFORM) uniform deferredFrameTransformBuffer {
    DeferredFrameTransform frameTransform;
};

vec2 getWidthHeight(int resolutionLevel) {
    return vec2(ivec2(frameTransform.infos.pixelInfo.zw) >> resolutionLevel);
}

vec2 getInvWidthHeight() {
    return frameTransform.infos.invPixelInfo.xy;
}

mat4 getProjection(int side) {
    return frameTransform.cameras[side]._projection;
}

mat4 getProjectionInverse(int side) {
    return frameTransform.cameras[side]._projectionInverse;
}

float getProjScaleEye() {
    return getProjection(0)[1][1];
}

float getProjScale(int resolutionLevel) {
    return getWidthHeight(resolutionLevel).y * getProjScaleEye() * 0.5;
}

mat4 getProjectionMono() {
    return frameTransform.infos.projectionMono;
}

// positive near distance of the projection
float getProjectionNear() {
    mat4 projection = getProjection(0);
    float planeC = projection[2][3] + projection[2][2];
    float planeD = projection[3][2];
    return planeD / planeC;
}

// positive far distance of the projection
float getPosLinearDepthFar() {
    return -frameTransform.infos.depthInfo.z;
}

mat4 getViewInverse(int side) {
    return frameTransform.cameras[side]._viewInverse;
}

mat4 getView(int side) {
    return frameTransform.cameras[side]._view;
}

mat4 getPreviousView(int side) {
    return frameTransform.cameras[side]._previousView;
}

mat4 getPreviousViewInverse(int side) {
    return frameTransform.cameras[side]._previousViewInverse;
}

bool isStereo() {
    return frameTransform.infos.stereoInfo.x > 0.0f;
}

float getStereoSideWidth(int resolutionLevel) {
    return float(int(frameTransform.infos.stereoInfo.y) >> resolutionLevel);
}

float getStereoSideHeight(int resolutionLevel) {
    return float(int(frameTransform.infos.pixelInfo.w) >> resolutionLevel);
}

vec2 getSideImageSize(int resolutionLevel) {
    return vec2(float(int(frameTransform.infos.stereoInfo.y) >> resolutionLevel), float(int(frameTransform.infos.pixelInfo.w) >> resolutionLevel));
}

int getStereoSideFromPixel(int xPos, int resolutionLevel) {
    int sideWidth = int(getStereoSideWidth(resolutionLevel));
    return int(xPos >= sideWidth && isStereo());
}

int getStereoSideFromPixel(int xPos) {
    return getStereoSideFromPixel(xPos, 0);
}

int getStereoSideFromFragCoord() {
    return getStereoSideFromPixel(int(gl_FragCoord.x), 0);
}

int getStereoSideFromUV(float uPos) {
    return int(uPos >= 0.5 && isStereo());
}

vec2 getStereoSideSize(int resolutionLevel) {
    return vec2(getStereoSideWidth(resolutionLevel), getStereoSideHeight(resolutionLevel));
}

ivec4 getStereoSideInfoFromWidth(int xPos, int sideWidth) {
    return ivec4((1 - int(xPos < sideWidth)) * ivec2(1, sideWidth), sideWidth, isStereo());
}

ivec4 getStereoSideInfo(int xPos, int resolutionLevel) {
    int sideWidth = int(getStereoSideWidth(resolutionLevel));
    return getStereoSideInfoFromWidth(xPos, sideWidth);
}

int getStereoSide(ivec4 sideInfo) {
    return sideInfo.x;
}

float evalZeyeFromZdb(float depth) {
    return frameTransform.infos.depthInfo.x / (depth * frameTransform.infos.depthInfo.y + frameTransform.infos.depthInfo.z);
}

float evalZdbFromZeye(float Zeye) {
    return (frameTransform.infos.depthInfo.x - Zeye * frameTransform.infos.depthInfo.z) / (Zeye * frameTransform.infos.depthInfo.y);
}

vec3 evalEyeNormal(vec3 C) {
    return normalize(cross(dFdx(C), dFdy(C)));
}

vec3 evalEyePositionFromZdb(int side, float Zdb, vec2 texcoord) {
    // compute the view space position using the depth
    vec3 clipPos;
    clipPos.xyz = vec3(texcoord.xy, Zdb) * 2.0 - 1.0;
    vec4 eyePos = getProjectionInverse(side) * vec4(clipPos.xyz, 1.0);
    return eyePos.xyz / eyePos.w;
}

vec3 evalEyePositionFromZeye(int side, float Zeye, vec2 texcoord) {
    float Zdb = evalZdbFromZeye(Zeye);
    return evalEyePositionFromZdb(side, Zdb, texcoord);
}

ivec2 getPixelPosTexcoordPosAndSide(in vec2 glFragCoord, out ivec2 pixelPos, out vec2 texcoordPos, out ivec4 stereoSide) {
    ivec2 fragPos = ivec2(glFragCoord.xy);

    stereoSide = getStereoSideInfo(fragPos.x, 0);

    pixelPos = fragPos;
    pixelPos.x -= stereoSide.y;

    texcoordPos = (vec2(pixelPos) + 0.5) * getInvWidthHeight();
    
    return fragPos;
}

<@endfunc@>


<@endif@>