TRenderMatrices.h

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2020, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */
#pragma once

#include <mrpt/math/CMatrixFixed.h>
#include <mrpt/math/TPoint3D.h>

namespace mrpt::opengl
{
/** Rendering state related to the projection and model-view matrices.
 * Used to store matrices that will be sent to shaders.
 *
 * The homogeneous coordinates of a rendered point comes from:
 *
 *  p = p_matrix * mv_matrix * [x y z 1.0]'
 *
 * \ingroup mrpt_opengl_grp
 */
struct TRenderMatrices
{
    TRenderMatrices() = default;

    /** The camera is here. */
    mrpt::math::TPoint3D eye = {0, 0, 0};

    /** The camera points to here */
    mrpt::math::TPoint3D pointing = {0, 0, 0};

    /** Up vector of the camera. */
    mrpt::math::TPoint3D up = {0, 0, 0};

    /** In pixels. This may be smaller than the total render window. */
    size_t viewport_width = 640, viewport_height = 480;
    /** Vertical FOV in degrees. */
    double FOV = 30.0f;
    /** Camera elev & azimuth, in radians. */
    double azimuth = .0, elev = .0;
    double eyeDistance = 1.0f;
    /** true: projective, false: ortho */
    bool is_projective = true;

    /** Projection matrix, computed by renderNormalScene() from all the
     * parameters above. Used in shaders. */
    mrpt::math::CMatrixFloat44 p_matrix;

    /** Model-view matrix. */
    mrpt::math::CMatrixFloat44 mv_matrix;

    /** Result of p_matrix * mv_matrix. Used in shaders.
     * Updated by renderSetOfObjects()
     */
    mrpt::math::CMatrixFloat44 pmv_matrix;

    /** Uses is_projective , vw,vh, etc. and computes p_matrix.
     * Replacement for obsolete: gluPerspective() and glOrtho() */
    void computeProjectionMatrix(float zmin, float zmax);

    /** Especial case for custom parameters of Orthographic projection.
     * Replacement for obsolete: glOrtho()*/
    void computeOrthoProjectionMatrix(
        float left, float right, float bottom, float top, float znear,
        float zfar);

    /** Updates the current p_matrix such that it "looks at" pointing, with
     * up vector "up". Replacement for deprecated OpenGL gluLookAt(). */
    void applyLookAt();

    /** Computes the normalized coordinates (range=[0,1]) on the current
     * rendering viewport of a
     * point with local coordinates (wrt to the current model matrix) of
     * (x,y,z).
     *  The output proj_z_depth is the real distance from the eye to the point.
     */
    void projectPoint(
        float x, float y, float z, float& proj_u, float& proj_v,
        float& proj_z_depth) const;

    /** Projects a point from global world coordinates into (u,v) pixel
     * coordinates. */
    void projectPointPixels(
        float x, float y, float z, float& proj_u_px, float& proj_v_px,
        float& proj_depth) const;
};

}  // namespace mrpt::opengl