### OpenCL Procedural Grass and Terrain Example ###

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DESCRIPTION:

This example shows how OpenCL can be used to create a procedural field of 

grass on a generated terrain model which is then rendered with OpenGL.  

Because OpenGL buffers are shared with OpenCL, the data can remain on the 

graphics card, thus eliminating the API overhead of creating and submitting 

the vertices from the host.

All geometry is generated on the compute device, and outputted into

a shared OpenGL buffer.  The terrain gets generated only within the 

visible arc covering the camera's view frustum to avoid the need for 

culling.  A page of grass is computed on the surface of the terrain as

bezier patches, and flow noise is applied to the angle of the blades

to simulate wind.  Multiple instances of grass are rendered at jittered

offsets to add more grass coverage without having to compute new pages.

Finally, a physically based sky shader (via OpenGL) is applied to 

the background to provide an environment for the grass.

Note that the .cl compute kernel file(s) and shader files (.vert and .frag)

are loaded and compiled at runtime.  The example source assumes that these 

files are in the same path as the built executable.

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BUILD REQUIREMENTS:

Mac OS X v10.6 or later

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RUNTIME REQUIREMENTS:

Mac OS X v10.6 or later with OpenCL 1.0

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PACKAGING LIST:

English.lproj

Grass.xcodeproj

Grass_Prefix.pch

Info.plist

ReadMe.txt

camera.cpp

camera.h

compute_engine.cpp

compute_engine.h

compute_math.cpp

compute_math.h

compute_types.h

data_loader.h

data_loader.m

grass_kernels.cl

grass_simulator.cpp

grass_simulator.h

grid_mesh.cpp

grid_mesh.h

icon.icns

main.cpp

main.m

mesh_renderer.cpp

mesh_renderer.h

shader.cpp

shader.h

sky.frag

sky.vert

terrain_kernels.cl

terrain_simulator.cpp

terrain_simulator.h

timing.h

version.plist

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CHANGES FROM PREVIOUS VERSIONS:

Version 1.0

- First version.

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Copyright (C) 2008 Apple Inc. All rights reserved.