CRenderizableShaderTexturedTriangles.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/img/CImage.h>
#include <mrpt/opengl/COpenGLBuffer.h>
#include <mrpt/opengl/COpenGLVertexArrayObject.h>
#include <mrpt/opengl/CRenderizable.h>
#include <mrpt/opengl/TTriangle.h>

namespace mrpt::opengl
{
/** Renderizable generic renderer for objects using the triangles-with-a-texture
 * shader.
 *
 *  \sa CTexturedPlane, opengl::CSetOfTexturedTriangles
 * \ingroup mrpt_opengl_grp
 */
class CRenderizableShaderTexturedTriangles : public virtual CRenderizable
{
    DEFINE_VIRTUAL_SERIALIZABLE(CRenderizableShaderTexturedTriangles)

   public:
    CRenderizableShaderTexturedTriangles() = default;
    virtual ~CRenderizableShaderTexturedTriangles() override;

    virtual shader_list_t requiredShaders() const override
    {
        return {DefaultShaderID::TEXTURED_TRIANGLES};
    }
    void render(const RenderContext& rc) const override;
    void renderUpdateBuffers() const override;

    /** Must be implemented in derived classes to update the geometric entities
     * to be drawn in "m_*_buffer" fields. */
    virtual void onUpdateBuffers_TexturedTriangles() = 0;

    // See base docs
    void freeOpenGLResources() override
    {
        m_vertexBuffer.destroy();
        m_vao.destroy();
    }

    /** Assigns a texture and a transparency image, and enables transparency (If
     * the images are not 2^N x 2^M, they will be internally filled to its
     * dimensions to be powers of two)
     * \note Images are copied, the original ones can be deleted.
     */
    void assignImage(
        const mrpt::img::CImage& img, const mrpt::img::CImage& imgAlpha);

    /** Assigns a texture image, and disable transparency.
     * \note Images are copied, the original ones can be deleted. */
    void assignImage(const mrpt::img::CImage& img);

    /** Similar to assignImage, but the passed images are moved in (move
     * semantic). */
    void assignImage(mrpt::img::CImage&& img, mrpt::img::CImage&& imgAlpha);

    /** Similar to assignImage, but with move semantics. */
    void assignImage(mrpt::img::CImage&& img);

    bool isLightEnabled() const { return m_enableLight; }
    void enableLight(bool enable = true) { m_enableLight = enable; }

    /** VERY IMPORTANT: If you use a multi-thread application, you MUST call
     * this from the same thread that will later destruct the object in order to
     * the OpenGL texture memory to be correctly deleted.
     *  Calling this method more than once has no effects. If you use one
     * thread, this method will be automatically called when rendering, so there
     * is no need to explicitly call it.
     */
    virtual void initializeTextures() const override;

    const mrpt::img::CImage& getTextureImage() const { return m_textureImage; }

    const mrpt::img::CImage& getTextureAlphaImage() const
    {
        return m_textureImageAlpha;
    }

    /** Enable linear interpolation of textures (default=false, use nearest
     * pixel) */
    void enableTextureLinearInterpolation(bool enable)
    {
        m_textureInterpolate = enable;
    }

   protected:
    /** List of triangles  \sa TTriangle */
    mutable std::vector<mrpt::opengl::TTriangle> m_triangles;

    void writeToStreamTexturedObject(mrpt::serialization::CArchive& out) const;
    void readFromStreamTexturedObject(mrpt::serialization::CArchive& in);

   private:
    bool m_enableLight = false;

    mutable unsigned int m_glTextureName{0};
    mutable bool m_texture_is_loaded{false};
    mutable mrpt::img::CImage m_textureImage{4, 4};
    mutable mrpt::img::CImage m_textureImageAlpha;

    /** Of the texture using "m_textureImageAlpha" */
    mutable bool m_enableTransparency{false};

    bool m_textureInterpolate = false;

    void unloadTexture();

    static unsigned int getNewTextureNumber();
    static void releaseTextureName(unsigned int i);

    mutable COpenGLBuffer m_vertexBuffer;
    mutable COpenGLVertexArrayObject m_vao;
};

}  // namespace mrpt::opengl