{ $values { "lower-left""A pair of numbers indicating the lower-left coordinates of the rectangle." } { "upper-right""The upper-right coordinates of the rectangle." } }
{ $description "Emits" { $link glVertex2d } " calls outlining the axis-aligned rectangle from " { $snippet "lower-left" } to { $snippet "upper-right" } " on the z=0 plane in counterclockwise order." } ;
{ $values { "status/f""The framebuffer error code, or " { $snippet "f" } " if the framebuffer is render-complete." } }
{ $description "Checks the framebuffer currently bound by " { $link glBindFramebufferEXT } " or " { $link with-framebuffer } " to see if it is incomplete, i.e., it is not ready to be rendered to." } ;
HELP:check-framebuffer
{ $description "Checks the framebuffer currently bound by " { $link glBindFramebufferEXT } " or " { $link with-framebuffer } " with " { $link framebuffer-incomplete? } ", and throws a descriptive error if the framebuffer is incomplete." } ;
HELP:with-framebuffer
{ $values { "id""The id of a framebuffer object." } { "quot""a quotation" } }
{ $description "Binds framebuffer " { $snippet "id" } " while calling " { $snippet "quot" } ", restoring the window framebuffer when finished." } ;
HELP:bind-texture-unit
{ $values { "id""The id of a texture object." } { "target""The texture target (e.g., " { $snippet "GL_TEXTURE_2D" } ")" } { "unit""The texture unit to bind (e.g., " { $snippet "GL_TEXTURE0" } ")" } }
{ $description "Binds texture " { $snippet "id" } " to texture target " { $snippet "target" } " of texture unit " { $snippet "unit" } ". Equivalent to " { $snippet "unit glActiveTexture target id glBindTexture" } "." } ;
{ $description "Wraps a quotation in " { $link glPushAttrib } "/" { $link glPopAttrib } " calls." } ;
HELP:sprite
{ $class-description "A sprite is an OpenGL texture together with a display list which renders a textured quad. Sprites are used to draw text in the UI. Sprites have the following slots:"
{ $list
{ { $link sprite-dlist } " - an OpenGL display list ID" }
{ $description "Calls the quotation with a translation by " { $snippet "loc" } " pixels applied to the current " { $link GL_MODELVIEW } " matrix, restoring the matrix when the quotation is done." } ;
{ $class-description { $snippet "gl-shader" } " is a predicate class comprising values returned by OpenGL to represent shader objects. The following words are provided for creating and manipulating these objects:"
{ $list
{ { $link <gl-shader> } " - Compile GLSL code into a shader object" }
"The derived predicate classes " { $link vertex-shader } " and " { $link fragment-shader } " are also defined for the two standard kinds of shader defined by the OpenGL specification." } ;
HELP:vertex-shader
{ $class-description { $snippet "vertex-shader" } " is the predicate class of " { $link gl-shader } " objects that refer to shaders of type " { $snippet "GL_VERTEX_SHADER" } ". In addition to the " { $snippet "gl-shader" } " words, the following vertex shader-specific functions are defined:"
{ $list
{ { $link <vertex-shader> } " - Compile GLSL code into a vertex shader object "}
}
} ;
HELP:fragment-shader
{ $class-description { $snippet "fragment-shader" } " is the predicate class of " { $link gl-shader } " objects that refer to shaders of type " { $snippet "GL_FRAGMENT_SHADER" } ". In addition to the " { $snippet "gl-shader" } " words, the following fragment shader-specific functions are defined:"
{ $list
{ { $link <fragment-shader> } " - Compile GLSL code into a fragment shader object "}
}
} ;
HELP:<gl-shader>
{ $values { "source""The GLSL source code to compile" } { "kind""The kind of shader to compile, such as " { $snippet "GL_VERTEX_SHADER" } " or " { $snippet "GL_FRAGMENT_SHADER" } } }
{ $description "Tries to compile the given GLSL source into a shader object. The returned object can be checked for validity by " { $link check-gl-shader } " or " { $link gl-shader-ok? } ". Errors and warnings generated by the GLSL compiler will be collected in the info log, available from " { $link gl-shader-info-log } ".\n\nWhen the shader object is no longer needed, it should be deleted using " { $link delete-gl-shader } " or else be attached to a " { $link gl-program } " object deleted using " { $link delete-gl-program } "." } ;
{ $description "Tries to compile the given GLSL source into a vertex shader object. Equivalent to " { $snippet "GL_VERTEX_SHADER <gl-shader>" } "." } ;
{ $description "Tries to compile the given GLSL source into a fragment shader object. Equivalent to " { $snippet "GL_FRAGMENT_SHADER <gl-shader>" } "." } ;
{ $description "Returns a boolean value indicating whether the given shader object compiled successfully. Compilation errors and warnings are available in the shader's info log, which can be gotten using " { $link gl-shader-info-log } "." } ;
{ $description "Throws an error containing the " { $link gl-shader-info-log } " for the shader object if it failed to compile. Otherwise, the shader object is left on the stack." } ;
{ $description "Retrieves the info log for " { $snippet "shader" } ", including any errors or warnings generated in compiling the shader object." } ;
HELP:gl-program
{ $class-description { $snippet "gl-program" } " is a predicate class comprising values returned by OpenGL to represent proram objects. The following words are provided for creating and manipulating these objects:"
{ $description "Creates a new GLSL program object, attaches all the shader objects in the " { $snippet "shaders" } " sequence, and attempts to link them. The returned object can be checked for validity by " { $link check-gl-program } " or " { $link gl-program-ok? } ". Errors and warnings generated by the GLSL linker will be collected in the info log, available from " { $link gl-program-info-log } ".\n\nWhen the program object and its attached shaders are no longer needed, it should be deleted using " { $link delete-gl-program } "." } ;
{ $description "Wrapper for " { $link <gl-program> } " for the simple case of compiling a single vertex shader and fragment shader and linking them into a GLSL program. Throws an exception if compiling or linking fails." } ;
{ $description "Returns a boolean value indicating whether the given program object linked successfully. Link errors and warnings are available in the program's info log, which can be gotten using " { $link gl-program-info-log } "." } ;
{ $description "Throws an error containing the " { $link gl-program-info-log } " for the program object if it failed to link. Otherwise, the program object is left on the stack." } ;
{ $description "Deletes the program object, invalidating it and releasing any resources allocated for it by the OpenGL implementation. Any attached " { $link gl-shader } "s are also deleted.\n\nIf the shader objects should be preserved, they should each be detached using " { $link detach-gl-program-shader } ". The program object can then be destroyed alone using " { $link delete-gl-program-only } "." } ;
{ $description "Enables " { $snippet "program" } " for all OpenGL calls made in " { $snippet "quot" } ". The fixed-function pipeline is restored at the end of " { $snippet "quot" } "." } ;
