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Up: 6.21 Procedural Texture Generation
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Now that we can create a single frequency noise function using the framebuffer,
we need to create the different octaves and to composite them into one texture.
For each octave:
The random translation is an attempt to minimize the amount of overlap between
each octave's texels; without it, every octave would use texels from the
same corner of the input image.
The accumulation is typically done with a scale factor that
controls the weight we want to give each octave.
- Scale the texture matrix by a power of 2 in both s and t.
- Translate the texture matrix by a random offset in both s and t.
- Set the texture wrap mode to GL_REPEAT for s and t.
- Draw a textured rectangle.
- Accumulate the color buffer contents.