Quote:
Originally Posted by Retro1234
So you can have a Dual Layer effect without using Dual Layer?
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Yes and no - key points:
* the number of layers can be any from 1 to 6 on OCS/ECS and 1 to 8 on AGA;
* the layers must have all the same width and horizontal scrolling offset;
* each layer has a freely defineable degree of transparency;
* each color has a freely defineable degree of transparency.
Quote:
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How many colours per layer on ECS?
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The only restrictions are that the total number of bitplanes used by the layers can be at most 6 and that the final colors with index >=32 are EHB (those are hardware limits that can't be broken). So it all depends on how many layers one chooses to have and their depth.
If one needs just 2 layers (as per your first question), all the possible allocations of the bitplanes are (first layer depth + second layer depth):
* 1 + 1/2/3/4/5
* 2 + 1/2/3/4
* 3 + 1/2/3
* 4 + 1/2
* 5 + 1
Example with 3 layers and 6 bitplanes:
* bottom layer (for background graphics): 2 bitplanes -> 4 colors;
* middle layer (for foreground graphics): 3 bitplanes -> 8 colors;
* top layer (for shadows): 1 bitplane -> 2 colors.
The first example in this video shows a 2-layer example that uses a 4+2 bitplanes split on OCS/ECS:
[ Show youtube player ]
The other examples are for AGA and help understand the system further.