MajorMagee
05-08-2006, 05:32 AM
Here's a technique to minimize the distortion in your sky textures.
Create a square blank image file.
Calculate the sky dome height based on the width. Width = 2 * Pi * Height
Fill in the top Width/(2 * Pi) with a starter color. This just helps with defining the edge of your sky dome for the next couple of steps.
Use the PhotoShop Polar Coordinate Filter (listed under Distort) to go from Rectangular to Polar. This will create a circle in the center of your square image file for you to create your sky dome. Remember that the primary light source should be at the 3 O'Clock position, and the outer portion of this circle will become the color for the vertical "mist curtain" along the horizon.
You may paint, or paste in photos of undistorted clouds around your sky dome. Keep their bases parallel to the edge of the circle. They should also be smaller and more densely spaced near the edges.
Once you're happy with your sky dome reverse the Polar Distortion Filter, and it will transform your sky dome back into a rectangular block along the top of your square file.
Now all that remains is to trim off everyting below Width/(2 * Pi) pixels, and you have a properly laid out sky bitmap in the correct width to height ratio to prevent any additional distortions during rendering.
Create a square blank image file.
Calculate the sky dome height based on the width. Width = 2 * Pi * Height
Fill in the top Width/(2 * Pi) with a starter color. This just helps with defining the edge of your sky dome for the next couple of steps.
Use the PhotoShop Polar Coordinate Filter (listed under Distort) to go from Rectangular to Polar. This will create a circle in the center of your square image file for you to create your sky dome. Remember that the primary light source should be at the 3 O'Clock position, and the outer portion of this circle will become the color for the vertical "mist curtain" along the horizon.
You may paint, or paste in photos of undistorted clouds around your sky dome. Keep their bases parallel to the edge of the circle. They should also be smaller and more densely spaced near the edges.
Once you're happy with your sky dome reverse the Polar Distortion Filter, and it will transform your sky dome back into a rectangular block along the top of your square file.
Now all that remains is to trim off everyting below Width/(2 * Pi) pixels, and you have a properly laid out sky bitmap in the correct width to height ratio to prevent any additional distortions during rendering.