Shader to turns black into transparency. Bloompass

[jscastro76]

I had exactly the same issue, but I managed to solve it modifiying UnrealBloomPass.js, but the issue is in the ShaderMaterial of UnrealBloomPass at the method getSeperableBlurMaterial.

You need to replace the fragmentShader by this code below and your pass background will consider the alpha channel:

fragmentShader:
	"#include <common>\
	varying vec2 vUv;\n\
	uniform sampler2D colorTexture;\n\
	uniform vec2 texSize;\
	uniform vec2 direction;\
	\
	float gaussianPdf(in float x, in float sigma) {\
		return 0.39894 * exp( -0.5 * x * x/( sigma * sigma))/sigma;\
	}\
	void main() {\n\
		  vec2 invSize = 1.0 / texSize;\
		  float fSigma = float(SIGMA);\
		  float weightSum = gaussianPdf(0.0, fSigma);\
		  float alphaSum = 0.0;\
		  vec3 diffuseSum = texture2D( colorTexture, vUv).rgb * weightSum;\
		  for( int i = 1; i < KERNEL_RADIUS; i ++ ) {\
			float x = float(i);\
			float w = gaussianPdf(x, fSigma);\
			vec2 uvOffset = direction * invSize * x;\
			vec4 sample1 = texture2D( colorTexture, vUv + uvOffset);\
			vec4 sample2 = texture2D( colorTexture, vUv - uvOffset);\
			diffuseSum += (sample1.rgb + sample2.rgb) * w;\
			alphaSum += (sample1.a + sample2.a) * w;\
			weightSum += 2.0 * w;\
		  }\
		  gl_FragColor = vec4(diffuseSum/weightSum, alphaSum/weightSum);\n\
	}"

I used the same official example with a cool background and it works perfectly.