1 INTRODUCTION 2 3 A helper module which provides glue to bind the software rasterizer to 4 the software t&l module. The main task of this module is to build 5 swrast vertices from the t&l vertex_buffer structs, and to use them to 6 perform triangle setup functions not implemented in the software 7 rasterizer. 8 9 The module implements a full set of functions to plug into the 10 t_vb_render.c driver interface (tnl->Driver.Render.*). 11 12 There are strong advantages to decoupling the software rasterizer from 13 the t&l module, primarily allowing hardware drivers better control 14 over fallbacks, the removal of implicit knowledge about the software 15 rasterizer in the t&l module, allowing the two modules to evolve 16 independently and allowing either to be substituted with equivalent 17 functionality from another codebase. 18 19 This module implements triangle/quad setup for offset, unfilled and 20 twoside-lit triangles. The software rasterizer doesn't handle these 21 primitives directly. 22 23 Hardware rasterization drivers typically use this module in situations 24 where no hardware rasterization is possible, ie during total 25 fallbacks. 26 27 STATE 28 29 To create and destroy the module: 30 31 GLboolean _swsetup_CreateContext( struct gl_context *ctx ); 32 void _swsetup_DestroyContext( struct gl_context *ctx ); 33 34 The module is not active by default, and must be installed by calling 35 _swrast_Wakeup(). This function installs internal swrast_setup 36 functions into all the tnl->Driver.Render driver hooks, thus taking 37 over the task of rasterization entirely: 38 39 void _swrast_Wakeup( struct gl_context *ctx ); 40 41 42 This module tracks state changes internally and maintains derived 43 values based on the current state. For this to work, the driver 44 ensure the following funciton is called whenever the state changes and 45 the swsetup module is 'awake': 46 47 void _swsetup_InvalidateState( struct gl_context *ctx, GLuint new_state ); 48 49 There is no explicit call to put the swsetup module to sleep. Simply 50 install other function pointers into all the tnl->Driver.Render.* 51 hooks, and (optionally) cease calling _swsetup_InvalidateState(). 52 53 DRIVER INTERFACE 54 55 The module offers a minimal driver interface: 56 57 void (*Start)( struct gl_context *ctx ); 58 void (*Finish)( struct gl_context *ctx ); 59 60 These are called before and after the completion of all swrast drawing 61 activity. As swrast doesn't call callbacks during triangle, line or 62 point rasterization, these are necessary to provide locking hooks for 63 some drivers. They may otherwise be left null. 64 65 66
