gallium/docs: table of texture formats and (x,y,z,w) tuples returned by TEX
Maybe someone can convert this into a real table instead of just
preformatted text.
diff --git a/src/gallium/docs/source/tgsi.rst b/src/gallium/docs/source/tgsi.rst
index 3e702ce..17fe76e 100644
--- a/src/gallium/docs/source/tgsi.rst
+++ b/src/gallium/docs/source/tgsi.rst
@@ -1441,3 +1441,32 @@
DirectX 9 uses INTEGER.
DirectX 10 uses HALF_INTEGER.
+
+
+
+Texture Sampling and Texture Formats
+------------------------------------
+
+This table shows how texture image components are returned as (x,y,z,w)
+tuples by TGSI texture instructions, such as TEX, TXD, and TXP.
+For reference, OpenGL and Direct3D convensions are shown as well::
+
+ Texture Components Gallium OpenGL DX9
+ ---------------------------------------------------------
+ R,G,B,A (R,G,B,A) (R,G,B,A) (R,G,B,A)
+ R,G,B (R,G,B,1) (R,G,B,1) (R,G,B,1)
+ R,G tbd (R,G,0,1) (R,G,1,1)
+ R tbd (R,0,0,1) (R,1,1,1)
+ A (0,0,0,A) (0,0,0,A) (0,0,0,A)
+ L (L,L,L,1) (L,L,L,1) (L,L,L,1)
+ LA (L,L,L,A) (L,L,L,A) (L,L,L,A)
+ I (I,I,I,I) (I,I,I,I) n/a
+ UV tbd (0,0,0,1)* (U,V,1,1)
+ Z tbd (Z,Z,Z,Z) or (0,Z,0,1)
+ (Z,Z,Z,1) or
+ (0,0,0,Z)**
+
+ Footnotes:
+ * per http://www.opengl.org/registry/specs/ATI/envmap_bumpmap.txt
+ ** depends on GL_DEPTH_TEXTURE_MODE state
+
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