How to Configure Camera and Viewport Settings in ArmorPaint: Complete Technical Guide

ArmorPaint stores all viewport and camera parameters in the global g_config object, loading them from config.json at startup and applying them through functions in viewport.c where UI controls, shortcuts, and scripts can modify values like FOV, camera type, and navigation speeds in real time.

ArmorPaint provides deep configurability for its 3D viewport and camera behavior through a centralized configuration system. Whether you need to adjust projection modes for precise texture painting or modify navigation speeds for ergonomic workflows, understanding how to configure camera and viewport settings in ArmorPaint allows you to customize the application at both the user interface and source code levels.

Understanding the Configuration Architecture

The configuration system relies on a global state object that bridges persistent storage and runtime application.

The Global Config Object (g_config)

All camera and viewport parameters reside in the global g_config structure defined in paint/sources/config.c. This object acts as the single source of truth for settings including camera_fov, camera_pan_speed, camera_zoom_speed, camera_rotation_speed, and camera_upside_down. When the application initializes, config_load() parses config.json and populates this structure with user-defined values or sensible defaults.

Persistence Layer (config.json)

Settings survive between sessions through JSON serialization. The config_save() function (located in paint/sources/config.c at lines 89-93) writes the current state of g_config back to disk, encoding floats via json_encode_f32() for parameters like "camera_fov". This ensures that custom viewport configurations remain intact across application restarts.

Camera Type and Projection Settings

ArmorPaint supports both perspective and orthographic projections, with distinct configuration paths for each.

Switching Between Perspective and Orthographic

The active camera type is stored in g_context->camera_type, which accepts either CAMERA_TYPE_PERSPECTIVE or CAMERA_TYPE_ORTHOGRAPHIC. When users trigger the view toggle shortcut (handled in paint/sources/util/util_shortcut.c at lines 303-305), the system calls viewport_update_camera_type() in paint/sources/viewport.c. This function swaps the projection matrix and immediately updates the viewport UI to reflect the change.

You can also toggle programmatically using MiniC scripts:

// Toggle camera type via embedded scripting
g_context->camera_type = (g_context->camera_type == CAMERA_TYPE_PERSPECTIVE) ?
                         CAMERA_TYPE_ORTHOGRAPHIC : CAMERA_TYPE_PERSPECTIVE;
viewport_update_camera_type(g_context->camera_type);

Field of View (FOV) Configuration

The default field of view persists in g_config->camera_fov and clamps between 0.3 and 1.4 radians. During viewport initialization (lines 24-33 of paint/sources/viewport.c), the system applies this value:

// From viewport.c - applying configuration to active camera
cam->data->fov = g_config->camera_fov;
camera_object_build_proj();

The Preferences panel exposes this through a slider defined in paint/sources/ui/box_preferences.c (lines 456-457), allowing real-time adjustments without restarting the application.

Navigation and Viewport Controls

Beyond projection matrices, ArmorPaint allows granular control over how users navigate the 3D space.

Pan, Zoom, and Rotation Speed

Three distinct speed modifiers control viewport navigation sensitivity:

• g_config->camera_pan_speed – Multiplies mouse deltas during middle-click dragging
• g_config->camera_zoom_speed – Scales scroll wheel or gesture inputs
• g_config->camera_rotation_speed – Adjusts orbit sensitivity around the model

These values are consumed by camera control functions in paint/sources/viewport.c such as camera_zoom() and camera_rotate(). Modify them programmatically to suit specific hardware or user preferences:

// Increase pan speed for tablet users
g_config->camera_pan_speed = 2.0f;
// Changes take effect immediately on next mouse interaction

Inverted Controls and Zoom Direction

For users requiring inverted navigation, g_config->camera_upside_down inverts the Y-axis interpretation during mouse movement calculations in viewport.c. Similarly, g_config->zoom_direction multiplies the zoom delta, allowing reversal of the standard scroll wheel behavior. Both settings serialize to config.json via the standard save mechanism.

Runtime Modification Methods

ArmorPaint exposes camera and viewport configuration through three distinct interfaces, each targeting different workflow requirements.

UI Controls and Preferences Panel

The primary method for adjusting settings involves the Preferences viewport panel implemented in paint/sources/ui/box_preferences.c. This interface provides sliders for FOV and navigation speeds that write directly to g_config:

// UI slider binding from box_preferences.c
ui_slider(&g_config->camera_fov, tr("Default Camera FoV"),
          0.3f, 1.4f, true, 100.0f, true, UI_ALIGN_RIGHT, true);

Changes propagate immediately because viewport.c reads from g_config during each frame's camera update cycle.

Keyboard Shortcuts

Direct shortcuts handle common toggles without menu navigation. The camera type toggle resides in paint/sources/util/util_shortcut.c, mapping keyboard inputs to context switches. These shortcuts bypass the UI layer and modify g_context->camera_type directly before invoking viewport updates.

Scripting with MiniC

For automated workflows or custom tools, ArmorPaint's embedded MiniC scripting API exposes the same configuration fields that the UI manipulates. Scripts can override settings temporarily for render captures or batch operations:

// Script-based FOV adjustment for render preview
g_config->camera_fov = 0.5f;  // Narrow FOV for detail work
// Perform operations...
config_save();  // Persist if desired

This approach mirrors the internal logic found in util_shortcut.c while allowing programmatic batching of configuration changes.

Persisting Custom Configurations

To ensure configuration changes survive application restarts, explicitly invoke the save mechanism after modifications:

// Save current g_config state to config.json
config_save();

This function (located in paint/sources/config.c) encodes all camera and viewport parameters into JSON format. The system typically calls this automatically on graceful exit, but manual invocation guarantees persistence during long sessions or after scripting changes.

Summary

• ArmorPaint centralizes camera and viewport settings in the global g_config object, distinct from the runtime g_context state that tracks active camera type.
• Configuration persistence relies on config.json, parsed by config_load() and written by config_save() in paint/sources/config.c.
• Projection settings including FOV and camera type apply through viewport.c, specifically via viewport_update_camera_type() and direct camera object manipulation.
• Navigation behavior—pan, zoom, and rotation speeds—scales according to g_config values consumed by input handlers in the viewport system.
• Three interfaces control these settings: the Preferences UI (box_preferences.c), keyboard shortcuts (util_shortcut.c), and MiniC scripting exposing the same underlying C structures.

Frequently Asked Questions

How do I reset the camera to default settings in ArmorPaint?

ArmorPaint applies default values when config.json cannot be found or parsed. To force a reset, close the application, delete the config.json file from your ArmorPaint directory, and restart. The config_load() function in paint/sources/config.c will regenerate the file with factory defaults for all camera and viewport parameters.

Can I switch to orthographic view for precise pixel alignment?

Yes, toggle between perspective and orthographic projection using the camera type shortcut defined in paint/sources/util/util_shortcut.c, or set g_context->camera_type = CAMERA_TYPE_ORTHOGRAPHIC via MiniC script. The viewport_update_camera_type() function in paint/sources/viewport.c handles the matrix recalculation and UI updates automatically.

Where does ArmorPaint store my custom FOV and speed settings?

All custom values persist in the config.json file in your application directory. The config_save() function writes fields like camera_fov, camera_pan_speed, and zoom_direction using json_encode_f32() and related serialization functions found in paint/sources/config.c.

Is it possible to script camera movements for automated rendering?

The embedded MiniC scripting environment exposes the complete g_config and g_context structures, allowing scripts to modify camera_fov, camera type, and navigation speeds before triggering renders. After adjustments, call config_save() to persist the configuration or allow the values to reset on next launch depending on your workflow requirements.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}