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'''OpenGL extension ARB.draw_instanced |
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This module customises the behaviour of the |
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OpenGL.raw.GL.ARB.draw_instanced to provide a more |
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Python-friendly API |
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Overview (from the spec) |
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A common use case in GL for some applications is to be able to |
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draw the same object, or groups of similar objects that share |
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vertex data, primitive count and type, multiple times. This |
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extension provides a means of accelerating such use cases while |
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restricting the number of API calls, and keeping the amount of |
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duplicate data to a minimum. |
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This extension introduces two draw calls which are conceptually |
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equivalent to a series of draw calls. Each conceptual call in |
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this series is considered an "instance" of the actual draw call. |
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This extension also introduces a read-only built-in variable to |
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GLSL which contains the "instance ID." This variable initially |
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contains 0, but increases by one after each conceptual draw call. |
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By using the instance ID or multiples thereof as an index into |
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a uniform array containing transform data, vertex shaders can |
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draw multiple instances of an object with a single draw call. |
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The official definition of this extension is available here: |
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http://www.opengl.org/registry/specs/ARB/draw_instanced.txt |
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''' |
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from OpenGL import platform, constant, arrays |
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from OpenGL import extensions, wrapper |
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import ctypes |
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from OpenGL.raw.GL import _types, _glgets |
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from OpenGL.raw.GL.ARB.draw_instanced import * |
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from OpenGL.raw.GL.ARB.draw_instanced import _EXTENSION_NAME |
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def glInitDrawInstancedARB(): |
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'''Return boolean indicating whether this extension is available''' |
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from OpenGL import extensions |
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return extensions.hasGLExtension( _EXTENSION_NAME ) |
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glDrawElementsInstancedARB=wrapper.wrapper(glDrawElementsInstancedARB).setInputArraySize( |
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'indices', None |
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) |
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