Implementation:Google deepmind Mujoco Render GL2 Header

Knowledge Sources	Google_deepmind_Mujoco
Domains	OpenGL, Graphics, 2D Rendering
Last Updated	2026-02-15 04:00 GMT

Overview

Header declaring the public API for MuJoCo's OpenGL 2D rendering functions including framebuffer management, pixel I/O, text rendering, and 2D figure drawing.

Description

This header provides the function declarations for all 2D rendering operations in MuJoCo. It declares MJAPI-exported functions for framebuffer selection (window/offscreen), pixel read/write/blit operations, auxiliary buffer management, text and overlay rendering, rectangle and label drawing, and 2D figure plotting. It also declares the internal mjr_textActual helper used by the text rendering implementation.

Usage

Included by source files that need to call MuJoCo's 2D rendering functions, and by the 3D renderer (render_gl3.c) which depends on 2D operations for compositing overlays and text onto the rendered scene.

Code Reference

Source Location

Repository: Google_deepmind_Mujoco
File: src/render/render_gl2.h
Lines: 1-84

Key Functions

// Restore the current buffer binding
MJAPI void mjr_restoreBuffer(const mjrContext* con);

// Internal text drawing (no OpenGL state init)
void mjr_textActual(int font, const char* txt, const mjrContext* con,
                    float x, float y, float z, float r, float g, float b);

// Framebuffer management
MJAPI void mjr_setBuffer(int framebuffer, mjrContext* con);
MJAPI void mjr_setAux(int index, const mjrContext* con);

// Pixel I/O
MJAPI void mjr_readPixels(unsigned char* rgb, float* depth,
                          mjrRect viewport, const mjrContext* con);
MJAPI void mjr_drawPixels(const unsigned char* rgb, const float* depth,
                          mjrRect viewport, const mjrContext* con);
MJAPI void mjr_blitBuffer(mjrRect src, mjrRect dst,
                          int flg_color, int flg_depth, const mjrContext* con);
MJAPI void mjr_blitAux(int index, mjrRect src, int left, int bottom,
                       const mjrContext* con);

// Text and overlay
MJAPI void mjr_text(int font, const char* txt, const mjrContext* con,
                    float x, float y, float r, float g, float b);
MJAPI void mjr_overlay(int font, int gridpos, mjrRect viewport,
                       const char* overlay, const char* overlay2, const mjrContext* con);

// Viewport and drawing
MJAPI mjrRect mjr_maxViewport(const mjrContext* con);
MJAPI void mjr_rectangle(mjrRect viewport, float r, float g, float b, float a);
MJAPI void mjr_label(mjrRect viewport, int font, const char* txt,
                     float r, float g, float b, float a, float rt, float gt, float bt,
                     const mjrContext* con);
MJAPI void mjr_figure(mjrRect viewport, mjvFigure* fig, const mjrContext* con);

Import

#include "render/render_gl2.h"

I/O Contract

Inputs

Name	Type	Required	Description
con	mjrContext* / const mjrContext*	Yes	Rendering context with OpenGL state
framebuffer	int	Yes (for setBuffer)	mjFB_WINDOW or mjFB_OFFSCREEN
viewport	mjrRect	Yes (for pixel/draw ops)	Viewport rectangle in framebuffer coordinates
font	int	Yes (for text ops)	Font index (mjtFont)
fig	mjvFigure*	Yes (for figure)	Figure data for 2D chart rendering

Outputs

Name	Type	Description
rgb	unsigned char*	Output buffer for pixel color data (via mjr_readPixels)
depth	float*	Output buffer for pixel depth data (via mjr_readPixels)
mjrRect	struct	Maximum viewport dimensions (via mjr_maxViewport)

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Principle

Implementation

Heuristic

Environment