class mrpt::opengl::LinesProxy

Overview

GPU-side proxy for rendering lines and wireframes.

This proxy handles rendering of any CVisualObject that uses the WIREFRAME shader, such as:

• CSetOfLines

• CSimpleLine

• CGridPlaneXY / CGridPlaneXZ

• CAxis

• Wireframe rendering of meshes

• Any object derived from VisualObjectParams_Lines

The proxy manages:

• Vertex buffer (line endpoints as pairs)

• Color buffer (per-vertex RGBA colors)

• Line rendering parameters (width, anti-aliasing)

• VAO for efficient attribute binding

Line rendering features:

• Variable line width

• Per-vertex colors

• Optional anti-aliasing (GL_LINE_SMOOTH)

• Alpha blending for transparency

Typical data flow:

1. compile() : Upload initial line vertices and colors to GPU

2. updateBuffers() : Re-upload when lines change

3. render() : Draw lines every frame

See also:

LinesProxyBase, mrpt::viz::VisualObjectParams_Lines

#include <mrpt/opengl/LinesProxy.h>

class LinesProxy: public mrpt::opengl::LinesProxyBase
{
public:
    // structs

    struct LineParams;

    // construction

    LinesProxy();

    // methods

    virtual void compile(const mrpt::viz::CVisualObject* sourceObj);
    virtual void updateBuffers(const mrpt::viz::CVisualObject* sourceObj);
    virtual void render(const RenderContext& rc) const;
    virtual const char* typeName() const;
};

Inherited Members

public:
    // typedefs

    typedef std::shared_ptr<RenderableProxy> Ptr;

    // fields

    mrpt::math::CMatrixFloat44 m_modelMatrix = mrpt::math::CMatrixFloat44::Identity();
    bool m_visible = true;
    bool m_castShadows = true;
    uint64_t m_changeCount = 0;
    mrpt::math::TPoint3Df m_sortPointLocal {0, 0, 0};

    // methods

    virtual void compile(const mrpt::viz::CVisualObject* sourceObj) = 0;
    virtual void updateBuffers(const mrpt::viz::CVisualObject* sourceObj);
    virtual void render(const RenderContext& rc) const = 0;
    virtual std::vector<shader_id_t> requiredShaders() const = 0;
    virtual bool castsShadows() const;
    virtual bool isTransparent() const;
    virtual bool isBackground() const;
    virtual shader_id_t shadowMapShader() const;
    virtual bool cullEligible() const;
    const std::optional<mrpt::math::TBoundingBoxf>& localBoundingBox() const;
    virtual const char* typeName() const;
    void setSourceObject(std::weak_ptr<const mrpt::viz::CVisualObject> obj);
    void setResourceScope(const void* scope);
    std::shared_ptr<const mrpt::viz::CVisualObject> getSourceObject() const;
    bool isSourceValid() const;
    bool sourceNeedsUpdate() const;
    RenderableProxy& operator = (const RenderableProxy&);
    RenderableProxy& operator = (RenderableProxy&&);
    virtual void compile(const mrpt::viz::CVisualObject* sourceObj);
    virtual void updateBuffers(const mrpt::viz::CVisualObject* sourceObj);
    virtual void render(const RenderContext& rc) const;
    virtual std::vector<shader_id_t> requiredShaders() const;
    virtual bool castsShadows() const;
    virtual const char* typeName() const;

Methods

virtual void compile(const mrpt::viz::CVisualObject* sourceObj)

Initial compilation: uploads object data to GPU.

This is called once when the proxy is first created. It should:

• Create OpenGL buffers (VBOs, VAOs, textures)

• Upload initial vertex/color/normal/texture data

• Cache any frequently-used values

Must be called from OpenGL context thread

After this call, the proxy should be ready to render

Parameters:

sourceObj

The abstract viz object (read-only access)

virtual void updateBuffers(const mrpt::viz::CVisualObject* sourceObj)

Incremental update: refreshes GPU buffers with changed data.

This is called when the data version of the source object changes (mrpt::viz::CVisualObject::dataVersion()). It should:

• Re-upload only the changed data (vertices, colors, etc.)

• Be as efficient as possible (don’t recompile everything)

Must be called from OpenGL context thread

Default implementation calls compile() - override for efficiency

Parameters:

sourceObj

The abstract viz object (read-only access)

virtual void render(const RenderContext& rc) const

Renders this object using the provided context.

This is called every frame for visible objects. It should:

• Bind appropriate buffers (VAO, VBO, textures)

• Set shader uniforms (model matrix, material properties, etc.)

• Issue draw calls (glDrawArrays, glDrawElements, etc.)

Must be called from OpenGL context thread

The shader program is already bound when this is called

Common matrices (P, V, M) are already uploaded by CompiledViewport

Parameters:

rc	Rendering context (shader, matrices, lights)

virtual const char* typeName() const

Returns a human-readable type name for this proxy.

Used for debugging and logging.