Bump map: Difference between revisions

Revision as of 04:40, 10 July 2008

A material's albedo (left) compared to its bump map.

The above material in-game.

A bump map is an RGB image that can be used to simulate a three-dimensional surface through a process known as normal mapping.

Each color channel in a bump map has a meaning:

The red channel defines horizontal facing (X-axis)
0 = left

128 = forward (facing viewer)

255 = right
The green channel defines vertical facing (Y-axis)
0 = up

128 = forward (facing viewer)

255 = down
The blue channel defines height (Z-axis)
0 = deepest

127 = maximum depth capable of receiving light

255 = at the material's surface

The three channels between them allow the engine to calculate a normal vector for every pixel, allowing it to generate shadows and highlights on a two-dimensional surface.

A bump map is largely useless for really flat surfaces like smooth concrete or metal, but even rough concrete sometimes has enough depth to it to make one worthwhile.

@@ Line 1: / Line 1: @@
-[[Image:Example_of_bump_mapping.jpg|right|thumb|350px|An example of normal maps being used in Half-Life 2. Click to enlarge.]]
+[[Image:Brickwall021a normalcompare.jpg|thumb|A material's [[albedo]] (left) compared to its bump map.]]
+[[Image:Example of bump mapping.jpg|thumb|The above material in-game.]]
-A texture used to give a material the illusion of depth through refracting light cast upon it (pixel by pixel). This shader method is called [[bump mapping]], and is perhaps the main reason that games such as Doom 3, FarCry, and Half-Life 2 are able to look so much better than previous games. The ''normal map'' is the successor to the [[heightmap]]. While heightmaps only used one channel to decode the height of each pixel, normal maps use all three:
+A '''bump map''' is an [[RGB]] image that can be used to simulate a three-dimensional surface through a process known as [[Wikipedia:Normal mapping|normal mapping]].
-* The '''red''' channel contains the horizontal facing (X-axis)
+Each color channel in a bump map has a meaning:
-*:0 = left
-*:128 = forward
-*:255 = right
-* The '''green''' channel includes the vertical facing (Y-axis)
-*:0 = up
-*:128 = forward
-*:255 = down
-* The '''blue''' channel decodes the height of the pixel (Z-axis)
-*:0 = deepest
-*:127 = maximum depth capable of receiving light
-*:255 = at the material's surface
-With these 3 channels, every pixel has a normal vector, means the engine knows in which direction the pixel is facing and can thereby calculate shadows and highlights.
+# The '''red''' channel defines horizontal facing (X-axis)
+#:0 = left
+#:128 = forward (facing viewer)
+#:255 = right
+# The '''green''' channel defines vertical facing (Y-axis)
+#:0 = up
+#:128 = forward (facing viewer)
+#:255 = down
+# The '''blue''' channel defines height (Z-axis)
+#:0 = deepest
+#:127 = maximum depth capable of receiving light
+#:255 = at the material's surface
-A normal map is largely useless for really flat surfaces like smooth concrete or metal, but even rough concrete sometimes has enough depth to it to make a normal map worthwhile.
+The three channels between them allow the engine to calculate a normal vector for every pixel, allowing it to generate shadows and highlights on a two-dimensional surface.
+A bump map is largely useless for really flat surfaces like smooth concrete or metal, but even rough concrete sometimes has enough depth to it to make one worthwhile.
 ==See also==
-*[[$bumpmap]] for normalmap syntax in [[VMT]] files.
+*[[$bumpmap]], for adding a bump map to a [[material]]
 *[[Normal Map Creation]]
 *[[Normal Map Creation in The GIMP]]
 *[[Normal2dudv]] a third party tool for converting normalmaps to Dx8-friendly [[du/dv maps]].
 *[http://planetpixelemporium.com/tutorialpages/normal.html An old article that explains the concept well.]
-*[[Wikipedia:Bump mapping]]
+*[[Wikipedia:Normal mapping]]
 *[[Bump mapping]] (merge?)

Bump map: Difference between revisions

Revision as of 04:40, 10 July 2008

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