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| A '''Program Object''' represents the compiled executable code, in the [[OpenGL Shading Language]], for one or more [[Shader]] stages. A program object is an object in OpenGL, but it does not use the standard [[OpenGL Object|OpenGL Object model.]]
| | #REDIRECT [[GLSL Object#Program objects]] |
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| == Creation ==
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| {{main|Shader Compilation}}
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| Empty program objects are created with this function:
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| {{funcdef|GLuint {{apifunc|glCreateProgram}}()}}
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| This will return an empty program object. Programs are deleted with {{apifunc|glDeleteProgram}}.
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| Once created, program objects must then be filled in with executable code. This is done by [[Shader Compilation|compiling shader objects and linking them into the program]].
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| === Pre-link setup ===
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| Before performing the linking steps for a shader, it is sometimes important to provide certain settings. OpenGL 3.3 or {{extref|explicit_attrib_location}} has replaced the need for most of this, by allowing shaders to provide these settings itself.
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| == Introspection ==
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| {{main|Program Introspection}}
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| A successfully linked program object can be queries for its various interfaces, so that the user can set uniforms and perform other upkeep on the object.
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| == State setting ==
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| Outside of the state used by the [[#Pre-link setup|pre-link setup]], program objects have the following mutable state:
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| * The current values of all [[Uniform_(GLSL)#Uniform_management|''active'' uniform variables]].
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| * The current bindings for any [[Interface_Block_(GLSL)#Uniform_blocks|Uniform blocks]].
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| * The current bindings for any [[Interface_Block_(GLSL)#Manual block binding|Shader storage blocks]].
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| Note that the last two pieces of state only need to be set if you did not [[Interface_Block_(GLSL)#Block_binding|set them directly in the shader]].
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| [[Category:Shaders]] | | [[Category:Shaders]] |
| [[Category:OpenGL Shading Language]] | | [[Category:OpenGL Shading Language]] |