qzdoom-gpl/wadsrc/static/shaders/glsl/exposurecombine.fp

in vec2 TexCoord;
out vec4 FragColor;

uniform sampler2D ExposureTexture;
uniform float ExposureBase;
uniform float ExposureMin;
uniform float ExposureScale;
uniform float ExposureSpeed;

void main()
{
	float light = texture(ExposureTexture, TexCoord).x;
	float exposureAdjustment = 1.0 / max(ExposureBase + light * ExposureScale, ExposureMin);
	FragColor = vec4(exposureAdjustment, 0.0, 0.0, ExposureSpeed);
}