RE_RenderFlush.h

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/*
 * PROPRIETARY INFORMATION.  This software is proprietary to
 * Side Effects Software Inc., and is not to be reproduced,
 * transmitted, or disclosed in any way without written permission.
 *
 * NAME:        RE_RenderFlush.h ( RE Library, C++)
 */

#ifndef __RE_RenderFlush__
#define __RE_RenderFlush__

#include "RE_API.h"
#include "RE_ShaderHandle.h"
#include "RE_Uniform.h"
#include "RE_RenderUI.h"
#include "RE_Server.h"
#include "RE_Types.h"
#include <UT/UT_BoundingRect.h>
#include <UT/UT_Rect.h>

class RE_Light;
class RE_PerContextData;

class RE_API RE_RenderFlush : public RE_RenderUI
{
public:
                                 RE_RenderFlush();
                                ~RE_RenderFlush() override;

    /// Tag used to distinguish overrides which try to only manipulate the
    /// cached state without issuing OpenGL commands.  Some commands with
    /// this tag may still have to query the OpenGL state.  These overrides
    /// are used to manipulate the cached state during Qt painting as that
    /// is what is restored when switching to OpenGL drawing.
    static struct CacheOnlyTag {} CacheOnly;

    /// Flag this object as being used to render into a 3D viewport.
    void                         setViewportRenderer();
    static RE_Font              &getViewportFont();

    /// Holds a pointer to per-context data we use to provide OGL buffers.
    void                         setContextData(RE_PerContextData *data);
    RE_PerContextData           *getContextData() { return myContextData; }

    // Override for setting the base Z value.
    void         setZStart(fpreal32 zStart) override;
    // Override to reuse OGL Buffers.
    void         draw(RE_Render *r) override;
    // Flush render commands built up to this point.
    bool         flushRender(bool render_complete = false);

    // TRANSFORMATION ------------------------------------------------------
    void         pushViewport();
    void         pushViewport(CacheOnlyTag);
    void         popViewport();
    void         popViewport(CacheOnlyTag);

    // Called by RE_OGLRender when our viewport changes.
    void         handleViewportUpdate(
                    const UT_DimRect &rect, RE_ViewportCoordSpace coord_space);
    void         handleViewportUpdate(
                    const UT_DimRect &rect, RE_ViewportCoordSpace coord_space,
                    CacheOnlyTag);
    void         handleScissorRectUpdate(
                    const UT_DimRect &rect, RE_ViewportCoordSpace coord_space);
    void         handleScissorRectUpdate(
                    const UT_DimRect &rect, RE_ViewportCoordSpace coord_space,
                    CacheOnlyTag);
    void         handleScissorEnableUpdate(bool enable);
    void         handleScissorEnableUpdate(bool enable, CacheOnlyTag);

    // Clipping plane support.
    void         clipPlaneDisable(int which);
    void         clipPlaneEnable(int which, const UT_Vector4D &plane);

    UT_Vector4D  planeToEyeCoords(const UT_Vector4D &plane);

    // NB: The following methods to push/pop the clip plane assume that they
    //     occur within a clipPlaneEnable()/clipPlaneDisable() block, hence
    //     the "replace" prefix.
    void         replacePushClipPlane(int which, const UT_Vector4D &plane,
                                      bool xform_to_eye_coords,
                                      RE_UniformStackEntry &stack_entry);
    void         replacePopClipPlane(int which,
                                     const RE_UniformStackEntry &stack_entry);

    void         getClipPlane(int which, UT_Vector4D &plane) const;

    // Matrix operations.
    void         pushMatrix(bool all_matrices = true,
                        RE_MatrixMode mmode = RE_MATRIX_VIEWING);
    void         popMatrix(bool all_matrices = true,
                        RE_MatrixMode mmode = RE_MATRIX_VIEWING);
    
    void         loadIdentityMatrix(RE_MatrixMode mmode = RE_MATRIX_VIEWING);
    void         loadMatrix(const UT_Matrix4 &m,
                        RE_MatrixMode mmode = RE_MATRIX_VIEWING);
    void         loadMatrix(const UT_DMatrix4 &m,
                        RE_MatrixMode mmode = RE_MATRIX_VIEWING);
    
    void         getMatrix(UT_Matrix4 &m,
                        RE_MatrixMode mmode = RE_MATRIX_VIEWING);
    void         getMatrix(UT_DMatrix4 &m,
                        RE_MatrixMode mmode = RE_MATRIX_VIEWING);
    
    void         multiplyMatrix(const UT_Matrix4 &m);
    void         multiplyMatrix(const UT_DMatrix4 &m);

    void         translate(float x, float y, float z = 0.0);
    void         scale(float x = 1.0, float y = 1.0, float z = 1.0);
    void         rotate(float angle, char axis);
    
    void         ortho2DW(float l, float r, float b, float t);
    void         orthoFromViewport2DI(const UT_DimRect &rect);
    void         ortho3DW(float l, float r, float b, float t,
                        float n, float f);
    void         window3DW(float l, float r, float b, float t,
                        float n, float f);

    // Generates a matrix equivalent to glOrtho.
    static UT_DMatrix4   getOrthoMatrix(float l, float r,
                                float b, float t,
                                float n, float f);
    // Generates a matrix equivalent to glFrustum.
    static UT_DMatrix4   getPerspectiveMatrix(float l, float r,
                                float b, float t,
                                float n, float f);
    // Generates a matrix equivalent to gluLookAt.
    static UT_DMatrix4   getLookatMatrix(const UT_Vector3F &eye,
                                const UT_Vector3F &target,
                                const UT_Vector3F &up);

    // Maps screen space coordinates to a world space position and a ray
    // into the scene. Lets you know where in the scene the mouse is.
    static bool  mapWorld(fpreal xs, fpreal ys,
                        const UT_DimRect &viewport,
                        const UT_Matrix4D &proj, 
                        const UT_Matrix4D &view,
                        fpreal *x1, fpreal *y1, fpreal *z1,
                        fpreal *x2, fpreal *y2, fpreal *z2);
    // Maps world space coordinates into a screen space position. This is the
    // pixel location of an object in the scene.
    static bool  mapScreen(fpreal xw, fpreal yw, fpreal zw, 
                        const UT_DimRect &viewport,
                        const UT_Matrix4D &proj, 
                        const UT_Matrix4D &view,
                        fpreal *xs, fpreal *ys);
 
    void         getProjectiveTextureTransform(const RE_Light *light,
                                               bool bias, UT_Matrix4 &mat);

    static void  debugOutput(bool enable);

    /// Set the device pixel ratio to use when scaling renders.
    void        setDevicePixelRatio(int ratio) { 
                    myDevicePixelRatio = ratio; 
                }

    /// Return the given numeric after scaling it by the renderer's
    /// device pixel ratio.
    int         devicePixelRatio() const {
                    if (RE_Server::useNewUISkin())
                    {
                        return myDevicePixelRatio;
                    }

                    return 1;
                }

protected:
    void         setRender(RE_Render *r);

private:
    void         flush(bool render_complete);
    void         updatePixelRatios();

    RE_Render                           *myRender;
    UT_Array<UT_DimRect>                 myViewportStack;
    UT_Array<RE_ViewportCoordSpace>      myViewportCoordSpaceStack;
    UT_Array<UT_DimRect>                 myScissorRectStack;
    UT_Array<bool>                       myScissorEnableStack;
    UT_Array<RE_ViewportCoordSpace>      myScissorCoordSpaceStack;
    UT_Array<UT_BoundingRect>            myOrthoStack;
    RE_Uniform                           myClipPlane0Uniform;
    RE_PerContextData                   *myContextData;

    /// Flag to prevent recursive flushing of render data.
    bool                                 myFlushing;

    /// Keeps track of whether this object is being used for dawing
    /// into a viewport or drawing regular UI.
    bool                                 myViewportRenderer;

    /// Cache our two available fonts.
    static RE_Font                      *theViewportFont;
    static RE_Font                      *theViewportSymbolFont;

    /// The device pixel ratio used to scale renders.
    /// This corresponds to the backing scale factor on macOS retina displays.
    int myDevicePixelRatio = 1;
};

inline bool
RE_RenderFlush::flushRender(bool render_complete)
{
    // Ignore nested flush calls.
    if (myFlushing)
        return false;
    
    // If this is the last flush of a render pass, we can reset our Z value
    // because the next thing we draw is a whole new render.
    if (render_complete)
        resetCurrentZ();

    // If we have nothing to do, bail out immediately.
    if (!hasAnyData())
        return false;

    flush(render_complete);

    return true;
}

#endif // __RE_RenderFlush__