GUI/GUI_PrimFramework.h

/*
 * Copyright (c) 2025
 *    Side Effects Software Inc.  All rights reserved.
 *
 * Redistribution and use of Houdini Development Kit samples in source and
 * binary forms, with or without modification, are permitted provided that the
 * following conditions are met:
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. The name of Side Effects Software may not be used to endorse or
 *    promote products derived from this software without specific prior
 *    written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY SIDE EFFECTS SOFTWARE `AS IS' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
 * NO EVENT SHALL SIDE EFFECTS SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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/*
 * COMMENTS:
 *      Framework for a render hook, with documentation. Does not actually do
 *      anything other than act as a commented template.
 */

#ifndef __GUI_PrimFramework__
#define __GUI_PrimFramework__

#include <GUI/GUI_PrimitiveHook.h>
#include <GR/GR_Primitive.h>
#include <RE/RE_RenderContext.h>

namespace HDK_Sample
{
    
/// The primitive render hook which creates GUI_PrimFramework objects.
class GUI_PrimFrameworkHook : public GUI_PrimitiveHook
{
public:
             GUI_PrimFrameworkHook();
            ~GUI_PrimFrameworkHook() override;

    /// This is called when a new GR_Primitive is required for a polysoup.
    /// In this case, the hook is augmenting the rendering of the polysoup by
    /// drawing a bounding box and a centroid around it.
    GR_Primitive *createPrimitive(const GT_PrimitiveHandle &gt_prim,
                                  const GEO_Primitive *geo_prim,
                                  const GR_RenderInfo *info,
                                  const char *cache_name,
                                  GR_PrimAcceptResult &processed) override;
};

/// Primitive object that is created by GUI_PrimFrameworkHook whenever a
/// a matching primitive is found.
class GUI_PrimFramework : public GR_Primitive
{
public:
                         GUI_PrimFramework(const GR_RenderInfo *info,
                                         const char *cache_name,
                                         const GEO_Primitive *prim);
                        ~GUI_PrimFramework() override;

    const char         *className() const override
                            { return "GUI_PrimFramework"; }

    /// See if the primitive can be consumed by this GR_Primitive. Only
    /// primitives from the same detail will ever be passed in. If the
    /// primitive hook specifies GUI_HOOK_COLLECT_PRIMITIVES then it is
    /// possible to have this called more than once for different GR_Primitives.
    /// A GR_Primitive that collects multiple GT or GEO primitives is
    /// responsible for keeping track of them (in a list, table, tree, etc).
    GR_PrimAcceptResult acceptPrimitive(GT_PrimitiveType t,
                                        int geo_type,
                                        const GT_PrimitiveHandle &ph,
                                        const GEO_Primitive *prim) override;

    /// Called whenever certain geometry-affecting display options are changed.
    /// This gives you the opportunity to see if you need to update the
    /// geometry based on what changed (you will need to cache the display
    /// options that you are interested in to determine this). Return:
    ///    DISPLAY_UNCHANGED  - no update required.
    ///    DISPLAY_CHANGED    - additional geometry attributes may be required
    ///    DISPLAY_VERSION_CHANGED - existing geometry must be redone
    /// If 'first_init' is true, this is being called to initialize any cached
    /// display options. The return value will be ignored. This will happen
    /// just after the primitive is created.
    GR_DispOptChange    displayOptionChange(const GR_DisplayOption &opts,
                                            bool first_init) override;
    
    /// If this primitive requires an update when the view changes, return true.
    bool                updateOnViewChange(
                                const GR_DisplayOption &) const override
                        { return false; }
    
    /// If updateOnViewChange() returns true, this is called when the view
    /// changes, but no other update reasons are present. Note that you do not
    /// have access to the primitive in this method, so you will need to cache
    /// anything relating to the primitive required by this method.
    void                viewUpdate(RE_RenderContext r,
                                   const GR_ViewUpdateParms &parms) override
                        {}
    /// For primitives that may need updating if the GL state changes, this
    /// hook allows you to perform a check if no update is otherwise required.
    /// Return true to have checkGLState() called. Returning true from that
    /// will trigger an update with the GR_GL_STATE_CHANGED reason set.
    /// @{
    bool                needsGLStateCheck(
                                const GR_DisplayOption &opts) const override
                        { return false; }
    bool                checkGLState(RE_RenderContext r,
                                     const GR_DisplayOption &opts) override
                        { return false; }
    /// @}
    
    /// Called whenever the parent detail is changed, draw modes are changed,
    /// selection is changed, or certain volatile display options are changed
    /// (such as level of detail).
    void                update(RE_RenderContext           r,
                               const GT_PrimitiveHandle  &primh,
                               const GR_UpdateParms      &p) override;

    /// return true if the primitive is in or overlaps the view frustum.
    /// always returning true will effectively disable frustum culling.
    bool                inViewFrustum(const UT_Matrix4D &objviewproj,
                                      const UT_BoundingBoxD *bbox) override
                            { return true; }

    /// Called to do a variety of render tasks (beauty, wire, shadow, object
    /// pick)
    void                render(RE_RenderContext        r,
                               GR_RenderMode           render_mode,
                               GR_RenderFlags          flags,
                               GR_DrawParms            draw_parms) override;
    
    /// Called when decoration 'decor' is required to be rendered.
    void                renderDecoration(RE_RenderContext r,
                                         GR_Decoration decor,
                                         const GR_DecorationParms &p) override;
    
    /// Render this primitive for picking, where pick_type is defined as one of
    /// the pickable bits in GU_SelectType.h (like GU_PICK_GEOPOINT)
    /// return the number of picks
    int                 renderPick(RE_RenderContext r,
                                   const GR_DisplayOption *opt,
                                   unsigned int pick_type,
                                   GR_PickStyle pick_style,
                                   bool has_pick_map) override;

private:
};


} // End HDK_Sample namespace.

#endif