2 * Mesa 3-D graphics library
5 * Copyright (C) 1999-2007 Brian Paul All Rights Reserved.
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28 * \file swrast/s_context.h
29 * \brief Software rasterization context and private types.
30 * \author Keith Whitwell <keith@tungstengraphics.com>
34 * \mainpage swrast module
36 * This module, software rasterization, contains the software fallback
37 * routines for drawing points, lines, triangles, bitmaps and images.
38 * All rendering boils down to writing spans (arrays) of pixels with
39 * particular colors. The span-writing routines must be implemented
40 * by the device driver.
47 #include "main/compiler.h"
48 #include "main/mtypes.h"
49 #include "main/texcompress.h"
50 #include "program/prog_execute.h"
52 #include "s_fragprog.h"
56 typedef void (*texture_sample_func
)(struct gl_context
*ctx
,
57 const struct gl_sampler_object
*samp
,
58 const struct gl_texture_object
*tObj
,
59 GLuint n
, const GLfloat texcoords
[][4],
60 const GLfloat lambda
[], GLfloat rgba
[][4]);
62 typedef void (_ASMAPIP blend_func
)( struct gl_context
*ctx
, GLuint n
,
64 GLvoid
*src
, const GLvoid
*dst
,
67 typedef void (*swrast_point_func
)( struct gl_context
*ctx
, const SWvertex
*);
69 typedef void (*swrast_line_func
)( struct gl_context
*ctx
,
70 const SWvertex
*, const SWvertex
*);
72 typedef void (*swrast_tri_func
)( struct gl_context
*ctx
, const SWvertex
*,
73 const SWvertex
*, const SWvertex
*);
76 typedef void (*validate_texture_image_func
)(struct gl_context
*ctx
,
77 struct gl_texture_object
*texObj
,
78 GLuint face
, GLuint level
);
83 * Bitmasks to indicate which rasterization options are enabled
87 #define ALPHATEST_BIT 0x001 /**< Alpha-test pixels */
88 #define BLEND_BIT 0x002 /**< Blend pixels */
89 #define DEPTH_BIT 0x004 /**< Depth-test pixels */
90 #define FOG_BIT 0x008 /**< Fog pixels */
91 #define LOGIC_OP_BIT 0x010 /**< Apply logic op in software */
92 #define CLIP_BIT 0x020 /**< Scissor or window clip pixels */
93 #define STENCIL_BIT 0x040 /**< Stencil pixels */
94 #define MASKING_BIT 0x080 /**< Do glColorMask or glIndexMask */
95 #define MULTI_DRAW_BIT 0x400 /**< Write to more than one color- */
96 /**< buffer or no buffers. */
97 #define OCCLUSION_BIT 0x800 /**< GL_HP_occlusion_test enabled */
98 #define TEXTURE_BIT 0x1000 /**< Texturing really enabled */
99 #define FRAGPROG_BIT 0x2000 /**< Fragment program enabled */
100 #define ATIFRAGSHADER_BIT 0x4000 /**< ATI Fragment shader enabled */
101 #define CLAMPING_BIT 0x8000 /**< Clamp colors to [0,1] */
104 #define _SWRAST_NEW_RASTERMASK (_NEW_BUFFERS| \
116 struct swrast_texture_image
;
120 * Fetch a texel from texture image at given position.
122 typedef void (*FetchTexelFunc
)(const struct swrast_texture_image
*texImage
,
123 GLint col
, GLint row
, GLint img
,
128 * Subclass of gl_texture_image.
129 * We need extra fields/info to keep tracking of mapped texture buffers,
130 * strides and Fetch functions.
132 struct swrast_texture_image
134 struct gl_texture_image Base
;
136 GLboolean _IsPowerOfTwo
; /**< Are all dimensions powers of two? */
138 /** used for mipmap LOD computation */
139 GLfloat WidthScale
, HeightScale
, DepthScale
;
142 * Byte stride between rows in ImageSlices.
144 * For compressed textures, this is the byte stride between one row of
145 * blocks and the next row of blocks.
147 * Only valid while one of the ImageSlices is mapped, and must be the same
148 * between all slices.
151 void **ImageSlices
; /**< if 3D texture: array [Depth] of offsets to
152 each 2D slice in 'Data', in texels */
153 GLubyte
*Map
; /**< Pointer to mapped image memory */
155 /** Malloc'd texture memory */
158 FetchTexelFunc FetchTexel
;
160 /** For fetching texels from compressed textures */
161 compressed_fetch_func FetchCompressedTexel
;
166 static inline struct swrast_texture_image
*
167 swrast_texture_image(struct gl_texture_image
*img
)
169 return (struct swrast_texture_image
*) img
;
173 static inline const struct swrast_texture_image
*
174 swrast_texture_image_const(const struct gl_texture_image
*img
)
176 return (const struct swrast_texture_image
*) img
;
181 * Subclass of gl_renderbuffer with extra fields needed for software
184 struct swrast_renderbuffer
186 struct gl_renderbuffer Base
;
188 GLubyte
*Buffer
; /**< The malloc'd memory for buffer */
190 /** These fields are only valid while buffer is mapped for rendering */
192 GLint RowStride
; /**< in bytes */
194 /** For span rendering */
200 static inline struct swrast_renderbuffer
*
201 swrast_renderbuffer(struct gl_renderbuffer
*img
)
203 return (struct swrast_renderbuffer
*) img
;
210 * \brief Per-context state that's private to the software rasterizer module.
214 /** Driver interface:
216 struct swrast_device_driver Driver
;
218 /** Configuration mechanisms to make software rasterizer match
219 * characteristics of the hardware rasterizer (if present):
221 GLboolean AllowVertexFog
;
222 GLboolean AllowPixelFog
;
224 /** Derived values, invalidated on statechanges, updated from
225 * _swrast_validate_derived():
227 GLbitfield _RasterMask
;
228 GLfloat _BackfaceSign
; /** +1 or -1 */
229 GLfloat _BackfaceCullSign
; /** +1, 0, or -1 */
230 GLboolean _PreferPixelFog
; /* Compute fog blend factor per fragment? */
231 GLboolean _TextureCombinePrimary
;
232 GLboolean _FogEnabled
;
233 GLboolean _DeferredTexture
;
235 /** List/array of the fragment attributes to interpolate */
236 GLuint _ActiveAttribs
[VARYING_SLOT_MAX
];
237 /** Same info, but as a bitmask of VARYING_BIT_x bits */
238 GLbitfield64 _ActiveAttribMask
;
239 /** Number of fragment attributes to interpolate */
240 GLuint _NumActiveAttribs
;
241 /** Indicates how each attrib is to be interpolated (lines/tris) */
242 GLenum _InterpMode
[VARYING_SLOT_MAX
]; /* GL_FLAT or GL_SMOOTH (for now) */
246 GLuint StippleCounter
; /**< Line stipple counter */
247 GLuint PointLineFacing
;
250 GLenum Primitive
; /* current primitive being drawn (ala glBegin) */
251 GLboolean SpecularVertexAdd
; /**< Add specular/secondary color per vertex */
253 void (*InvalidateState
)( struct gl_context
*ctx
, GLbitfield new_state
);
256 * When the NewState mask intersects these masks, we invalidate the
257 * Point/Line/Triangle function pointers below.
260 GLbitfield InvalidatePointMask
;
261 GLbitfield InvalidateLineMask
;
262 GLbitfield InvalidateTriangleMask
;
266 * Device drivers plug in functions for these callbacks.
267 * Will be called when the GL state change mask intersects the above masks.
270 void (*choose_point
)( struct gl_context
* );
271 void (*choose_line
)( struct gl_context
* );
272 void (*choose_triangle
)( struct gl_context
* );
276 * Current point, line and triangle drawing functions.
279 swrast_point_func Point
;
280 swrast_line_func Line
;
281 swrast_tri_func Triangle
;
285 * Placeholders for when separate specular (or secondary color) is
286 * enabled but texturing is not.
289 swrast_point_func SpecPoint
;
290 swrast_line_func SpecLine
;
291 swrast_tri_func SpecTriangle
;
295 * Typically, we'll allocate a sw_span structure as a local variable
296 * and set its 'array' pointer to point to this object. The reason is
297 * this object is big and causes problems when allocated on the stack
300 SWspanarrays
*SpanArrays
;
301 SWspanarrays
*ZoomedArrays
; /**< For pixel zooming */
304 * Used to buffer N GL_POINTS, instead of rendering one by one.
308 /** Internal hooks, kept up to date by the same mechanism as above.
310 blend_func BlendFunc
;
311 texture_sample_func TextureSample
[MAX_TEXTURE_IMAGE_UNITS
];
313 /** Buffer for saving the sampled texture colors.
314 * Needed for GL_ARB_texture_env_crossbar implementation.
316 GLfloat
*TexelBuffer
;
318 validate_texture_image_func ValidateTextureImage
;
320 /** State used during execution of fragment programs */
321 struct gl_program_machine FragProgMachine
;
323 /** Temporary arrays for stencil operations. To avoid large stack
327 GLubyte
*buf1
, *buf2
, *buf3
, *buf4
;
334 _swrast_validate_derived( struct gl_context
*ctx
);
337 _swrast_update_texture_samplers(struct gl_context
*ctx
);
340 /** Return SWcontext for the given struct gl_context */
341 static inline SWcontext
*
342 SWRAST_CONTEXT(struct gl_context
*ctx
)
344 return (SWcontext
*) ctx
->swrast_context
;
347 /** const version of above */
348 static inline const SWcontext
*
349 CONST_SWRAST_CONTEXT(const struct gl_context
*ctx
)
351 return (const SWcontext
*) ctx
->swrast_context
;
356 * Called prior to framebuffer reading/writing.
357 * For drivers that rely on swrast for fallback rendering, this is the
358 * driver's opportunity to map renderbuffers and textures.
361 swrast_render_start(struct gl_context
*ctx
)
363 SWcontext
*swrast
= SWRAST_CONTEXT(ctx
);
364 if (swrast
->Driver
.SpanRenderStart
)
365 swrast
->Driver
.SpanRenderStart(ctx
);
369 /** Called after framebuffer reading/writing */
371 swrast_render_finish(struct gl_context
*ctx
)
373 SWcontext
*swrast
= SWRAST_CONTEXT(ctx
);
374 if (swrast
->Driver
.SpanRenderFinish
)
375 swrast
->Driver
.SpanRenderFinish(ctx
);
380 _swrast_span_render_start(struct gl_context
*ctx
);
383 _swrast_span_render_finish(struct gl_context
*ctx
);
386 _swrast_map_textures(struct gl_context
*ctx
);
389 _swrast_unmap_textures(struct gl_context
*ctx
);
392 _swrast_teximage_slice_height(struct gl_texture_image
*texImage
);
395 _swrast_map_texture(struct gl_context
*ctx
, struct gl_texture_object
*texObj
);
398 _swrast_unmap_texture(struct gl_context
*ctx
, struct gl_texture_object
*texObj
);
402 _swrast_map_renderbuffers(struct gl_context
*ctx
);
405 _swrast_unmap_renderbuffers(struct gl_context
*ctx
);
409 * Size of an RGBA pixel, in bytes, for given datatype.
411 #define RGBA_PIXEL_SIZE(TYPE) \
412 ((TYPE == GL_UNSIGNED_BYTE) ? 4 * sizeof(GLubyte) : \
413 ((TYPE == GL_UNSIGNED_SHORT) ? 4 * sizeof(GLushort) \
414 : 4 * sizeof(GLfloat)))
419 * Fixed point arithmetic macros
421 #ifndef FIXED_FRAC_BITS
422 #define FIXED_FRAC_BITS 11
425 #define FIXED_SHIFT FIXED_FRAC_BITS
426 #define FIXED_ONE (1 << FIXED_SHIFT)
427 #define FIXED_HALF (1 << (FIXED_SHIFT-1))
428 #define FIXED_FRAC_MASK (FIXED_ONE - 1)
429 #define FIXED_INT_MASK (~FIXED_FRAC_MASK)
430 #define FIXED_EPSILON 1
431 #define FIXED_SCALE ((float) FIXED_ONE)
432 #define FIXED_DBL_SCALE ((double) FIXED_ONE)
433 #define FloatToFixed(X) (IROUND((X) * FIXED_SCALE))
434 #define FixedToDouble(X) ((X) * (1.0 / FIXED_DBL_SCALE))
435 #define IntToFixed(I) ((I) << FIXED_SHIFT)
436 #define FixedToInt(X) ((X) >> FIXED_SHIFT)
437 #define FixedToUns(X) (((unsigned int)(X)) >> FIXED_SHIFT)
438 #define FixedCeil(X) (((X) + FIXED_ONE - FIXED_EPSILON) & FIXED_INT_MASK)
439 #define FixedFloor(X) ((X) & FIXED_INT_MASK)
440 #define FixedToFloat(X) ((X) * (1.0F / FIXED_SCALE))
441 #define PosFloatToFixed(X) FloatToFixed(X)
442 #define SignedFloatToFixed(X) FloatToFixed(X)
447 * XXX these macros are just bandages for now in order to make
448 * CHAN_BITS==32 compile cleanly.
449 * These should probably go elsewhere at some point.
451 #if CHAN_TYPE == GL_FLOAT
452 #define ChanToFixed(X) (X)
453 #define FixedToChan(X) (X)
455 #define ChanToFixed(X) IntToFixed(X)
456 #define FixedToChan(X) FixedToInt(X)
461 * For looping over fragment attributes in the pointe, line
462 * triangle rasterizers.
464 #define ATTRIB_LOOP_BEGIN \
467 for (a = 0; a < swrast->_NumActiveAttribs; a++) { \
468 const GLuint attr = swrast->_ActiveAttribs[a];
470 #define ATTRIB_LOOP_END } }
474 * Return the address of a pixel value in a mapped renderbuffer.
476 static inline GLubyte
*
477 _swrast_pixel_address(struct gl_renderbuffer
*rb
, GLint x
, GLint y
)
479 struct swrast_renderbuffer
*srb
= swrast_renderbuffer(rb
);
480 const GLint bpp
= _mesa_get_format_bytes(rb
->Format
);
481 const GLint rowStride
= srb
->RowStride
;
484 /* NOTE: using <= only because of s_tritemp.h which gets a pixel
485 * address but doesn't necessarily access it.
487 assert(x
<= (GLint
) rb
->Width
);
488 assert(y
<= (GLint
) rb
->Height
);
490 return (GLubyte
*) srb
->Map
+ y
* rowStride
+ x
* bpp
;