GPU Pro 7

4. Real-Time Volumetric Cloudscapes 107

Figure 4.14. The “base” cloud shape with coverage applied.

Here is how it looks in code:

// Cloud coverage is stored in weather data ’ s red channel .

float cloud_coverage = weather_data . r ;

// Use remap to apply the cloud coverage attribute .

float base_cloud_with_coverage = Remap ( base_cloud ,

cloud_coverage , 1.0 , 0.0 , 1.0) ;

// Multiply the result by the cloud coverage attribute so

// that smaller clouds are lighter and more aesthetically

// pleasing .

base_cloud_with_coverage ∗= cloud_coverage ;

The result of these steps is shown in Figure 4.14. The base cloud is still low

detail but it is beginning to