Diffstat (limited to 'doc/specs/vulkan/appendices/VK_NV_clip_space_w_scaling.txt')
1 files changed, 15 insertions, 14 deletions
diff --git a/doc/specs/vulkan/appendices/VK_NV_clip_space_w_scaling.txt b/doc/specs/vulkan/appendices/VK_NV_clip_space_w_scaling.txt
index 642b759..416d240 100644
@@ -18,27 +18,28 @@ to the final post-processed image.
This extension provides a mechanism to render VR scenes at a non-uniform
resolution, in particular a resolution that falls linearly from the center
towards the edges.
-This is achieved by scaling the "w" coordinate of the vertices in the clip
-space before perspective divide.
-The clip space "w" coordinate of the vertices can: be offset as of a
-function of "x" and "y" coordinates as follows:
+This is achieved by scaling the [eq]#w# coordinate of the vertices in the
+clip space before perspective divide.
+The clip space [eq]#w# coordinate of the vertices can: be offset as of a
+function of [eq]#x# and [eq]#y# coordinates as follows:
- w' = w + Ax + By
+[eq]#w' = w + Ax + By#
In the intended use case for viewport position scaling, an application
should use a set of 4 viewports, one for each of the 4 quadrants of a
Cartesian coordinate system.
Each viewport is set to the dimension of the image, but is scissored to the
quadrant it represents.
-The application should specify A and B coefficients of the w-scaling
-equation above, that have the same value, but different signs, for each of
-The signs of A and B should match the signs of X and Y for the quadrant that
-they represent such that the value of "w'" will always be greater than or
-equal to the original "w" value for the entire image.
-Since the offset to "w", (Ax + By), is always positive and increases with
-the absolute values of "x" and "y", the effective resolution will fall off
-linearly from the center of the image to its edges.
+The application should specify [eq]#A# and [eq]#B# coefficients of the
+[eq]#w#-scaling equation above, that have the same value, but different
+signs, for each of the viewports.
+The signs of [eq]#A# and [eq]#B# should match the signs of [eq]#x# and
+[eq]#y# for the quadrant that they represent such that the value of [eq]#w'#
+will always be greater than or equal to the original [eq]#w# value for the
+Since the offset to [eq]#w#, ([eq]#Ax + By#), is always positive, and
+increases with the absolute values of [eq]#x# and [eq]#y#, the effective
+resolution will fall off linearly from the center of the image to its edges.
=== New Object Types