Bloom Post-Processing >=26.1

BloomPostEffect

Core class that manages the entire bloom input, downsampling, upsampling, blur, and blending process.

Initialization

// Obtain via ALRendering
BloomPostEffect bloom = ALRendering.getBloomPostEffect();

// Or construct directly (customizable parameters)
BloomPostEffect bloom = new BloomPostEffect(bloomIntensity, threshold, sensitivity);

The constructor creates BloomParametersUbo, BlurParametersUbo, BloomPipelineParametersUbo and corresponding GPU buffers, and initializes the downsampleTargets[] and upsampleTargets[] target textures.

Main Methods

Method	Description
beginFrame()	Clears temporary textures and dirty flags at the start of each frame
drawBloomed(BloomRenderCallback)	Registers objects that need additional rendering on the bloom input texture
process(modelViewMatrix, featureRenderDispatcher)	Executes the complete bloom processing pipeline
resize(width, height)	Resizes all target textures when the window size changes
markDirty()	Manually marks as needing reprocessing

process Flow

1. runBloomDraws ← Execute all BloomRenderCallbacks, render to bloomInputTarget
2. doDownSample  ← Progressively downsample bloom texture (half size each step)
3. doUpSample    ← Progressively upsample using 5×5 Gaussian kernel, blending current layer + previous layer
4. applyBloom    ← Blend bloom result back into the main render target

Callback Interface

@FunctionalInterface
public interface BloomRenderCallback {
    void render(SubmitNodeCollector nodeCollector, PoseStack poseStack);
}

bloom.drawBloomed((nodeCollector, poseStack) -> {
    // Render objects that should bloom onto bloomInputTarget
    // e.g., rendering glowing items, blocks, etc.
});

Internal Passes

Pass	Pipeline	Shader	Description
DownSample	DOWNSAMPLE	down_sample.fsh	Average 4 pixels, halve resolution
UpSample	UPSAMPLE	up_sample.fsh + blur.fsh	5×5 Gaussian blur, blend with previous layer
ApplyBloom	APPLY_BLOOM	apply_bloom.fsh	Blend bloom texture with main framebuffer

Blend Formula

color + bloom * pow(threshold, luminance * sensitivity)

Bloom UBOs

BloomParametersUbo

public class BloomParametersUbo extends UboObject<BloomParametersUbo> {
    float bloomIntensity;       // Bloom intensity
    float bloomBlendThreshold;   // Blend threshold
    float luminanceSensitivity;  // Luminance sensitivity
}

BlurParametersUbo

public class BlurParametersUbo extends UboObject<BlurParametersUbo> {
    Vec2f direction;        // Blur direction
    float sampleStepLength; // Sample step length
    float colorMultiplier;  // Color multiplier
}

BloomPipelineParametersUbo

public class BloomPipelineParametersUbo extends UboObject<BloomPipelineParametersUbo> {
    Vec2f resolution; // Render resolution
    int frameIndex;   // Frame index
}

TransformsUbo

public class TransformsUbo extends UboObject<TransformsUbo> {
    Matrix4f projMat; // Orthographic projection matrix
}

Usage Example

// Get the bloom instance
BloomPostEffect bloom = ALRendering.getBloomPostEffect();

// Register bloom draw callbacks
bloom.drawBloomed((nodeCollector, poseStack) -> {
    // Render glowing objects
    ItemRenderer.renderItem(itemStack, poseStack, ...);
});

// Manually mark as dirty
bloom.markDirty();