overte/libraries/gpu/src/gpu/Transform.slh

<!
//  gpu/TransformState.slh
//
//  Created by Sam Gateau on 2/10/15.
//  Copyright 2013 High Fidelity, Inc.
//
//  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 GPU_TRANSFORM_STATE_SLH@>
<@def GPU_TRANSFORM_STATE_SLH@>

<@func declareStandardTransform()@>
struct TransformObject { 
    mat4 _model;
    mat4 _modelInverse;
};

struct TransformCamera { 
    mat4 _view;
    mat4 _viewInverse;
    mat4 _projectionViewUntranslated;
    mat4 _projection;
    mat4 _projectionInverse;
    vec4 _viewport;
};

in ivec2 _drawCallInfo;

layout(std140) buffer transformObjectBuffer {
    TransformObject _object[];
};
TransformObject getTransformObject() {
    return _object[_drawCallInfo.x];
}

layout(std140) uniform transformCameraBuffer {
    TransformCamera _camera;
};
TransformCamera getTransformCamera() {
    return _camera;
}
<@endfunc@>

<@func transformCameraViewport(cameraTransform, viewport)@>
     <$viewport$> = <$cameraTransform$>._viewport;
<@endfunc@>

<@func transformModelToClipPos(cameraTransform, objectTransform, modelPos, clipPos)@>
    <!// Equivalent to the following but hoppefully a tad more accurate
      //return camera._projection * camera._view * object._model * pos; !>
    { // transformModelToClipPos
        vec4 _eyepos = (<$objectTransform$>._model * <$modelPos$>) + vec4(-<$modelPos$>.w * <$cameraTransform$>._viewInverse[3].xyz, 0.0);
        <$clipPos$> = <$cameraTransform$>._projectionViewUntranslated * _eyepos;
    }
<@endfunc@>

<@func $transformModelToEyeAndClipPos(cameraTransform, objectTransform, modelPos, eyePos, clipPos)@>
    <!// Equivalent to the following but hoppefully a tad more accurate
      //return camera._projection * camera._view * object._model * pos; !>
    { // transformModelToClipPos
        vec4 _worldpos = (<$objectTransform$>._model * <$modelPos$>);
        <$eyePos$> = (<$cameraTransform$>._view * _worldpos);
        vec4 _eyepos =(<$objectTransform$>._model * <$modelPos$>) + vec4(-<$modelPos$>.w * <$cameraTransform$>._viewInverse[3].xyz, 0.0);
        <$clipPos$> = <$cameraTransform$>._projectionViewUntranslated * _eyepos;
      //  <$eyePos$> = (<$cameraTransform$>._projectionInverse * <$clipPos$>);
    }
<@endfunc@>

<@func transformModelToWorldPos(objectTransform, modelPos, worldPos)@>
    { // transformModelToWorldPos
        <$worldPos$> = (<$objectTransform$>._model * <$modelPos$>);
    }
<@endfunc@>

<@func transformModelToEyeDir(cameraTransform, objectTransform, modelDir, eyeDir)@>
    { // transformModelToEyeDir
        vec3 mr0 = vec3(<$objectTransform$>._modelInverse[0].x, <$objectTransform$>._modelInverse[1].x, <$objectTransform$>._modelInverse[2].x);
        vec3 mr1 = vec3(<$objectTransform$>._modelInverse[0].y, <$objectTransform$>._modelInverse[1].y, <$objectTransform$>._modelInverse[2].y);
        vec3 mr2 = vec3(<$objectTransform$>._modelInverse[0].z, <$objectTransform$>._modelInverse[1].z, <$objectTransform$>._modelInverse[2].z);

        vec3 mvc0 = vec3(dot(<$cameraTransform$>._viewInverse[0].xyz, mr0), dot(<$cameraTransform$>._viewInverse[0].xyz, mr1), dot(<$cameraTransform$>._viewInverse[0].xyz, mr2));
        vec3 mvc1 = vec3(dot(<$cameraTransform$>._viewInverse[1].xyz, mr0), dot(<$cameraTransform$>._viewInverse[1].xyz, mr1), dot(<$cameraTransform$>._viewInverse[1].xyz, mr2));
        vec3 mvc2 = vec3(dot(<$cameraTransform$>._viewInverse[2].xyz, mr0), dot(<$cameraTransform$>._viewInverse[2].xyz, mr1), dot(<$cameraTransform$>._viewInverse[2].xyz, mr2));

        <$eyeDir$> = vec3(dot(mvc0, <$modelDir$>), dot(mvc1, <$modelDir$>), dot(mvc2, <$modelDir$>));
    }
<@endfunc@>

<@func transformEyeToWorldDir(cameraTransform, eyeDir, worldDir)@>
    { // transformEyeToWorldDir
        <$worldDir$> = vec3(<$cameraTransform$>._viewInverse * vec4(<$eyeDir$>.xyz, 0.0));
    }
<@endfunc@>

<@func transformClipToEyeDir(cameraTransform, clipPos, eyeDir)@>
    { // transformClipToEyeDir
        <$eyeDir$> = vec3(<$cameraTransform$>._projectionInverse * vec4(<$clipPos$>.xyz, 1.0)); // Must be 1.0 here
    }
<@endfunc@>

<@func $transformModelToEyePos(cameraTransform, objectTransform, modelPos, eyePos)@>
    <!// Equivalent to the following but hoppefully a tad more accurate
    //return camera._view * object._model * pos; !>
    { // transformModelToEyePos
        vec4 _worldpos = (<$objectTransform$>._model * vec4(<$modelPos$>.xyz, 1.0));
        <$eyePos$> = (<$cameraTransform$>._view * _worldpos);
    }
<@endfunc@>

<@func transformEyeToClipPos(cameraTransform, eyePos, clipPos)@>
    { // transformEyeToClipPos
        <$clipPos$> = <$cameraTransform$>._projection * vec4(<$eyePos$>.xyz, 1.0);
    }
<@endfunc@>

<@endif@>