UePointLightShadow

UePointLightShadow manages shadows for UePointLight using a cube shadow map approach (6 faces). This implementation enables point lights to cast shadows in all directions.

Overview

• Creates 6 UePerspectiveCamera instances with a 90° FOV (one per cube face).
• Generates a temporary surface atlas of 3x2 to render all faces in a single texture.
• Provides a unified s_pointShadowMap sampler for shaders to sample the atlas.
• Computes 6 lightSpaceMatrix (projection * view) matrices—one for each face.
• Provides methods to update cameras based on the light position and to change shadow map resolution.

Implementation details (GameMaker)

Unique Engine uses a custom approach to handle point shadows in GameMaker. Instead of multiple render target switches, the engine renders all 6 faces into a single 3x2 atlas using temporary surfaces and then copies them to the final shadow map. This ensures compatibility and performance.

Shader usage

The standard shader sh_ue_standard automatically handles point shadows if enabled. It uses the u_uePointShadowEnabled uniform and the s_pointShadowMap sampler. The distance-based shadow is calculated using the light position and the far/near planes.

API

• UePointLightShadow(data = {}) - Constructor.
  • data.shadowNear - Near plane distance for cameras (default 0.5).
  • data.shadowFar - Far plane distance for cameras (default 500).

Key methods:

• updateMapSize(width, height) - Update resolution of all shadow maps.
• updateCameras(lightPosition) - Position all 6 cameras at the light's position and update matrices.
• setRange(near, far) - Set near/far for all cameras.
• getTextures() - Returns an array with the 6 shadow map textures.
• dispose() - Release resources.

Best practices

• Use even resolutions (e.g. 512, 1024) for all faces to keep quality balanced.
• Keep shadowFar as small as possible to improve depth precision.

Example

pointLight = new UePointLight(c_white, 1, 400);
pointLight.castShadow = true;
pointLight.position.set(0, 0, 50);
pointLight.shadow.updateMapSize(512, 512);
scene.add(pointLight);