Environment Mapping
Environment Mapping | map projection environmentOne of the forms of ibl is a method of texture overlay that simulates the effect of mirror reflections on the surface. As a result of the use of the environment map rendering on the reflections it takes much less time than when using a "fair" tracing.
Environment Mapping involves the use of one or more of the textures with The ����������������� or ������������������� reflections. The projection of the textures on the surface of the model occurs by the specific transformation texture coordinates. There are several methods of projection environment maps:
Sphere Mapping (spherical projection) - as the environment map is used the only texture, forming the surface of the imaginary of a hemisphere, the object from the viewer. This is the easiest and most effective method, but not realistic, as with any angle the viewer sees the same reflection. This method is also known as the Mirror Ball ("mirror ball").
Cube Mapping (cubic projection) - as a reader ���������� uses six projection, forming the six sides of the imaginary cube surrounding the object. As a result, the effect is fully reflected from any point of the surface. The original images obtained by the preliminary or dynamic rendering. This method allows you to get the most realistic result at the cost of the high cost of video memory.
Equirectangular Mapping (������������������ projection - a method of projection used in cartography. As the environment map is used only the texture covering the imaginary sphere around the object. Allows you to get a realistic result at minimum cost of video memory (artifacts of projection are the "poles", but they are usually not very visible). In the rendering of real time, this method has been widely only with the advent of shaders, as on a fixed line it is not maintained.
Dual-Paraboloid Mapping (the projection of dual paraboloid) is one of the most modern methods. Displays the top and bottom of the hemisphere of environment in two textures. This method has little artifacts (if not take a small deviation along the equator") and is the best compromise between memory consumption and the quality of the result.
See also Reflection Mapping.
