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more docs (Klaus Niederkruger)

This commit is contained in:
Brian Paul 2003-05-01 22:45:57 +00:00
parent 92f9785c72
commit e53aa5022f
1 changed files with 30 additions and 14 deletions
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44
src/mesa/tnl/t_context.h
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@ -37,24 +37,39 @@
* necessary transformations (rotations, clipping, vertex shader etc.)
* and passes then the output to the rasterizer.
*
* The gl_pipeline contains an array of stages. The stages are
* black-boxes, which are described by gl_pipeline_stage.
* The function _tnl_run_pipeline (in file t_pipeline.c) applies all
* the stages to the vertex buffer.
* Note that the last stage in the pipeline is the rasterizer.
* The gl_pipeline contains the array of all stages, which should be
* applied. Each stage is a black-box, which is described by an
* gl_pipeline_stage. The function ::_tnl_run_pipeline applies all the
* stages to the vertex_buffer TNLcontext::vb, where the vertex data
* is stored. The last stage in the pipeline is the rasterizer.
*
* _tnl_run_pipeline is called either, when the vertex buffer is full or
* when a state change flushes the pipeline.
* Note that _tnl_run_pipeline is not called directly but via
* tnl_device_driver::RunPipeline, which is stored in TNLcontext::Driver.
* The initial vertex_buffer data may either come from an ::immediate
* structure or client vertex_arrays or display lists:
*
* The 'immediate' structure records all the GL commands issued between
* glBegin and glEnd. The 'vertex_buffer' structure stores the vertex
* data as its passed through the pipeline stages. The initial vertex_buffer
* data may either come from the 'immediate' structure or client vertex
* arrays or display lists.
*
* - The ::immediate structure records all the GL commands issued between
* glBegin and glEnd. \n
* The structure accumulates data, until it is either full or it is
* flushed (usually by a state change). Before starting then the pipeline,
* the collected vertex data in ::immediate has to be pushed into
* TNLcontext::vb.
* This happens in ::_tnl_vb_bind_immediate. The pipeline is then run by
* calling tnl_device_driver::RunPipeline = ::_tnl_run_pipeline, which
* is stored in TNLcontext::Driver. \n
* An ::immediate does (for performance reasons) usually not finish with a
* glEnd, and hence it also does not need to start with a glBegin.
* This means that the last vertices of one ::immediate may need to be
* saved for the next one.
*
*
* - NOT SURE ABOUT THIS: The vertex_arrays structure is used to handle
* glDrawArrays etc. \n
* Here, the data of the vertex_arrays is copied by ::_tnl_vb_bind_arrays
* into TNLcontext::vb, so that the pipeline can be started.
*/
/* What is ELT? */
#ifndef _T_CONTEXT_H
#define _T_CONTEXT_H
@ -168,6 +183,7 @@
/**
* \struct immediate
* Stores everything that can take place between a glBegin and glEnd.
* Adjacent glBegin/glEnd pairs are stored back-to-back when there's no
* state changes between them.