2 * Mesa 3-D graphics library
5 * Copyright (C) 1999-2007 Brian Paul All Rights Reserved.
7 * Permission is hereby granted, free of charge, to any person obtaining a
8 * copy of this software and associated documentation files (the "Software"),
9 * to deal in the Software without restriction, including without limitation
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14 * The above copyright notice and this permission notice shall be included
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17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
18 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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27 * \file swrast/s_context.h
28 * \brief Software rasterization context and private types.
29 * \author Keith Whitwell <keith@tungstengraphics.com>
33 * \mainpage swrast module
35 * This module, software rasterization, contains the software fallback
36 * routines for drawing points, lines, triangles, bitmaps and images.
37 * All rendering boils down to writing spans (arrays) of pixels with
38 * particular colors. The span-writing routines must be implemented
39 * by the device driver.
46 #include "main/compiler.h"
47 #include "main/mtypes.h"
48 #include "program/prog_execute.h"
53 typedef void (*texture_sample_func
)(struct gl_context
*ctx
,
54 const struct gl_texture_object
*tObj
,
55 GLuint n
, const GLfloat texcoords
[][4],
56 const GLfloat lambda
[], GLfloat rgba
[][4]);
58 typedef void (_ASMAPIP blend_func
)( struct gl_context
*ctx
, GLuint n
,
60 GLvoid
*src
, const GLvoid
*dst
,
63 typedef void (*swrast_point_func
)( struct gl_context
*ctx
, const SWvertex
*);
65 typedef void (*swrast_line_func
)( struct gl_context
*ctx
,
66 const SWvertex
*, const SWvertex
*);
68 typedef void (*swrast_tri_func
)( struct gl_context
*ctx
, const SWvertex
*,
69 const SWvertex
*, const SWvertex
*);
72 typedef void (*validate_texture_image_func
)(struct gl_context
*ctx
,
73 struct gl_texture_object
*texObj
,
74 GLuint face
, GLuint level
);
79 * Bitmasks to indicate which rasterization options are enabled
83 #define ALPHATEST_BIT 0x001 /**< Alpha-test pixels */
84 #define BLEND_BIT 0x002 /**< Blend pixels */
85 #define DEPTH_BIT 0x004 /**< Depth-test pixels */
86 #define FOG_BIT 0x008 /**< Fog pixels */
87 #define LOGIC_OP_BIT 0x010 /**< Apply logic op in software */
88 #define CLIP_BIT 0x020 /**< Scissor or window clip pixels */
89 #define STENCIL_BIT 0x040 /**< Stencil pixels */
90 #define MASKING_BIT 0x080 /**< Do glColorMask or glIndexMask */
91 #define MULTI_DRAW_BIT 0x400 /**< Write to more than one color- */
92 /**< buffer or no buffers. */
93 #define OCCLUSION_BIT 0x800 /**< GL_HP_occlusion_test enabled */
94 #define TEXTURE_BIT 0x1000 /**< Texturing really enabled */
95 #define FRAGPROG_BIT 0x2000 /**< Fragment program enabled */
96 #define ATIFRAGSHADER_BIT 0x4000 /**< ATI Fragment shader enabled */
97 #define CLAMPING_BIT 0x8000 /**< Clamp colors to [0,1] */
100 #define _SWRAST_NEW_RASTERMASK (_NEW_BUFFERS| \
114 * \brief Per-context state that's private to the software rasterizer module.
118 /** Driver interface:
120 struct swrast_device_driver Driver
;
122 /** Configuration mechanisms to make software rasterizer match
123 * characteristics of the hardware rasterizer (if present):
125 GLboolean AllowVertexFog
;
126 GLboolean AllowPixelFog
;
128 /** Derived values, invalidated on statechanges, updated from
129 * _swrast_validate_derived():
131 GLbitfield _RasterMask
;
132 GLfloat _BackfaceSign
; /** +1 or -1 */
133 GLfloat _BackfaceCullSign
; /** +1, 0, or -1 */
134 GLboolean _PreferPixelFog
; /* Compute fog blend factor per fragment? */
135 GLboolean _TextureCombinePrimary
;
136 GLboolean _FogEnabled
;
137 GLboolean _DeferredTexture
;
139 /** List/array of the fragment attributes to interpolate */
140 GLuint _ActiveAttribs
[FRAG_ATTRIB_MAX
];
141 /** Same info, but as a bitmask */
142 GLbitfield _ActiveAttribMask
;
143 /** Number of fragment attributes to interpolate */
144 GLuint _NumActiveAttribs
;
145 /** Indicates how each attrib is to be interpolated (lines/tris) */
146 GLenum _InterpMode
[FRAG_ATTRIB_MAX
]; /* GL_FLAT or GL_SMOOTH (for now) */
148 /* Accum buffer temporaries.
150 GLboolean _IntegerAccumMode
; /**< Storing unscaled integers? */
151 GLfloat _IntegerAccumScaler
; /**< Implicit scale factor */
155 GLuint StippleCounter
; /**< Line stipple counter */
156 GLuint PointLineFacing
;
159 GLenum Primitive
; /* current primitive being drawn (ala glBegin) */
160 GLboolean SpecularVertexAdd
; /**< Add specular/secondary color per vertex */
162 void (*InvalidateState
)( struct gl_context
*ctx
, GLbitfield new_state
);
165 * When the NewState mask intersects these masks, we invalidate the
166 * Point/Line/Triangle function pointers below.
169 GLbitfield InvalidatePointMask
;
170 GLbitfield InvalidateLineMask
;
171 GLbitfield InvalidateTriangleMask
;
175 * Device drivers plug in functions for these callbacks.
176 * Will be called when the GL state change mask intersects the above masks.
179 void (*choose_point
)( struct gl_context
* );
180 void (*choose_line
)( struct gl_context
* );
181 void (*choose_triangle
)( struct gl_context
* );
185 * Current point, line and triangle drawing functions.
188 swrast_point_func Point
;
189 swrast_line_func Line
;
190 swrast_tri_func Triangle
;
194 * Placeholders for when separate specular (or secondary color) is
195 * enabled but texturing is not.
198 swrast_point_func SpecPoint
;
199 swrast_line_func SpecLine
;
200 swrast_tri_func SpecTriangle
;
204 * Typically, we'll allocate a sw_span structure as a local variable
205 * and set its 'array' pointer to point to this object. The reason is
206 * this object is big and causes problems when allocated on the stack
209 SWspanarrays
*SpanArrays
;
210 SWspanarrays
*ZoomedArrays
; /**< For pixel zooming */
213 * Used to buffer N GL_POINTS, instead of rendering one by one.
217 /** Internal hooks, kept up to date by the same mechanism as above.
219 blend_func BlendFunc
;
220 texture_sample_func TextureSample
[MAX_TEXTURE_IMAGE_UNITS
];
222 /** Buffer for saving the sampled texture colors.
223 * Needed for GL_ARB_texture_env_crossbar implementation.
225 GLfloat
*TexelBuffer
;
227 validate_texture_image_func ValidateTextureImage
;
229 /** State used during execution of fragment programs */
230 struct gl_program_machine FragProgMachine
;
236 _swrast_validate_derived( struct gl_context
*ctx
);
239 _swrast_update_texture_samplers(struct gl_context
*ctx
);
242 /** Return SWcontext for the given struct gl_context */
243 static INLINE SWcontext
*
244 SWRAST_CONTEXT(struct gl_context
*ctx
)
246 return (SWcontext
*) ctx
->swrast_context
;
249 /** const version of above */
250 static INLINE
const SWcontext
*
251 CONST_SWRAST_CONTEXT(const struct gl_context
*ctx
)
253 return (const SWcontext
*) ctx
->swrast_context
;
258 * Called prior to framebuffer reading/writing.
259 * For drivers that rely on swrast for fallback rendering, this is the
260 * driver's opportunity to map renderbuffers and textures.
263 swrast_render_start(struct gl_context
*ctx
)
265 SWcontext
*swrast
= SWRAST_CONTEXT(ctx
);
266 if (swrast
->Driver
.SpanRenderStart
)
267 swrast
->Driver
.SpanRenderStart(ctx
);
271 /** Called after framebuffer reading/writing */
273 swrast_render_finish(struct gl_context
*ctx
)
275 SWcontext
*swrast
= SWRAST_CONTEXT(ctx
);
276 if (swrast
->Driver
.SpanRenderFinish
)
277 swrast
->Driver
.SpanRenderFinish(ctx
);
283 * Size of an RGBA pixel, in bytes, for given datatype.
285 #define RGBA_PIXEL_SIZE(TYPE) \
286 ((TYPE == GL_UNSIGNED_BYTE) ? 4 * sizeof(GLubyte) : \
287 ((TYPE == GL_UNSIGNED_SHORT) ? 4 * sizeof(GLushort) \
288 : 4 * sizeof(GLfloat)))
293 * Fixed point arithmetic macros
295 #ifndef FIXED_FRAC_BITS
296 #define FIXED_FRAC_BITS 11
299 #define FIXED_SHIFT FIXED_FRAC_BITS
300 #define FIXED_ONE (1 << FIXED_SHIFT)
301 #define FIXED_HALF (1 << (FIXED_SHIFT-1))
302 #define FIXED_FRAC_MASK (FIXED_ONE - 1)
303 #define FIXED_INT_MASK (~FIXED_FRAC_MASK)
304 #define FIXED_EPSILON 1
305 #define FIXED_SCALE ((float) FIXED_ONE)
306 #define FIXED_DBL_SCALE ((double) FIXED_ONE)
307 #define FloatToFixed(X) (IROUND((X) * FIXED_SCALE))
308 #define FixedToDouble(X) ((X) * (1.0 / FIXED_DBL_SCALE))
309 #define IntToFixed(I) ((I) << FIXED_SHIFT)
310 #define FixedToInt(X) ((X) >> FIXED_SHIFT)
311 #define FixedToUns(X) (((unsigned int)(X)) >> FIXED_SHIFT)
312 #define FixedCeil(X) (((X) + FIXED_ONE - FIXED_EPSILON) & FIXED_INT_MASK)
313 #define FixedFloor(X) ((X) & FIXED_INT_MASK)
314 #define FixedToFloat(X) ((X) * (1.0F / FIXED_SCALE))
315 #define PosFloatToFixed(X) FloatToFixed(X)
316 #define SignedFloatToFixed(X) FloatToFixed(X)
321 * XXX these macros are just bandages for now in order to make
322 * CHAN_BITS==32 compile cleanly.
323 * These should probably go elsewhere at some point.
325 #if CHAN_TYPE == GL_FLOAT
326 #define ChanToFixed(X) (X)
327 #define FixedToChan(X) (X)
329 #define ChanToFixed(X) IntToFixed(X)
330 #define FixedToChan(X) FixedToInt(X)
335 * For looping over fragment attributes in the pointe, line
336 * triangle rasterizers.
338 #define ATTRIB_LOOP_BEGIN \
341 for (a = 0; a < swrast->_NumActiveAttribs; a++) { \
342 const GLuint attr = swrast->_ActiveAttribs[a];
344 #define ATTRIB_LOOP_END } }