Class TrianglesProxy

Nested Relationships

Nested Types

Inheritance Relationships

Base Type

Class Documentation

class TrianglesProxy : public mrpt::opengl::TrianglesProxyBase

GPU-side proxy for rendering triangle meshes.

This proxy handles rendering of any CVisualObject that uses triangle-based shaders, such as:

  • CMesh

  • CBox

  • CSphere

  • CCylinder

  • Any object derived from VisualObjectParams_Triangles

The proxy manages:

  • Vertex buffer (3D triangle vertices)

  • Normal buffer (per-vertex normals for lighting)

  • Color buffer (per-vertex RGBA colors)

  • VAO for efficient attribute binding

  • Lighting and material parameters

  • Face culling modes

Triangle rendering features:

  • Phong lighting (ambient, diffuse, specular)

  • Per-vertex colors with optional lighting modulation

  • Face culling (FRONT, BACK, NONE)

  • Shadow casting (2-pass rendering)

  • Material properties (shininess)

Shader selection:

  • Normal rendering: TRIANGLES_LIGHT or TRIANGLES_NO_LIGHT

  • Shadow 1st pass: TRIANGLES_SHADOW_1ST (depth only)

  • Shadow 2nd pass: TRIANGLES_SHADOW_2ND (with shadow mapping)

Typical data flow:

  1. compile(): Upload triangle vertices, normals, colors to GPU

  2. updateBuffers(): Re-upload when mesh changes

  3. render(): Draw triangles with appropriate shader every frame

See also

TrianglesProxyBase, mrpt::viz::VisualObjectParams_Triangles

RenderableProxy Interface Implementation

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

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

Note

Must be called from OpenGL context thread

Note

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) override

Incremental update: refreshes GPU buffers with changed data.

This is called when the source object’s dirty flag is set (hasToUpdateBuffers() returns true). It should:

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

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

Note

Must be called from OpenGL context thread

Note

Default implementation calls compile() - override for efficiency

Parameters:

sourceObj – The abstract viz object (read-only access)

virtual void render(const RenderContext &rc) const override

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.)

Note

Must be called from OpenGL context thread

Note

The shader program is already bound when this is called

Note

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

Parameters:

rc – Rendering context (shader, matrices, lights)

virtual std::vector<shader_id_t> requiredShaders() const override

Returns the list of shader programs this object needs.

Most objects use a single shader, but some may use multiple (e.g., different shaders for shadow map pass vs. normal rendering).

Returns:

Vector of shader IDs, typically with 1 element

inline virtual const char *typeName() const override

Returns a human-readable type name for this proxy. Used for debugging and logging.

Public Functions

TrianglesProxy() = default
~TrianglesProxy() override = default