2 * Mesa 3-D graphics library
4 * Copyright (C) 1999-2007 Brian Paul All Rights Reserved.
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27 * \file swrast/s_context.h
28 * \brief Software rasterization context and private types.
29 * \author Keith Whitwell <keithw@vmware.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 "main/texcompress.h"
49 #include "program/prog_execute.h"
51 #include "s_fragprog.h"
55 typedef void (*texture_sample_func
)(struct gl_context
*ctx
,
56 const struct gl_sampler_object
*samp
,
57 const struct gl_texture_object
*tObj
,
58 GLuint n
, const GLfloat texcoords
[][4],
59 const GLfloat lambda
[], GLfloat rgba
[][4]);
61 typedef void (*blend_func
)(struct gl_context
*ctx
, GLuint n
,
63 GLvoid
*src
, const GLvoid
*dst
,
66 typedef void (*swrast_point_func
)( struct gl_context
*ctx
, const SWvertex
*);
68 typedef void (*swrast_line_func
)( struct gl_context
*ctx
,
69 const SWvertex
*, const SWvertex
*);
71 typedef void (*swrast_tri_func
)( struct gl_context
*ctx
, const SWvertex
*,
72 const SWvertex
*, const SWvertex
*);
75 typedef void (*validate_texture_image_func
)(struct gl_context
*ctx
,
76 struct gl_texture_object
*texObj
,
77 GLuint face
, GLuint level
);
82 * Bitmasks to indicate which rasterization options are enabled
86 #define ALPHATEST_BIT 0x001 /**< Alpha-test pixels */
87 #define BLEND_BIT 0x002 /**< Blend pixels */
88 #define DEPTH_BIT 0x004 /**< Depth-test pixels */
89 #define FOG_BIT 0x008 /**< Fog pixels */
90 #define LOGIC_OP_BIT 0x010 /**< Apply logic op in software */
91 #define CLIP_BIT 0x020 /**< Scissor or window clip pixels */
92 #define STENCIL_BIT 0x040 /**< Stencil pixels */
93 #define MASKING_BIT 0x080 /**< Do glColorMask or glIndexMask */
94 #define MULTI_DRAW_BIT 0x400 /**< Write to more than one color- */
95 /**< buffer or no buffers. */
96 #define OCCLUSION_BIT 0x800 /**< GL_HP_occlusion_test enabled */
97 #define TEXTURE_BIT 0x1000 /**< Texturing really enabled */
98 #define FRAGPROG_BIT 0x2000 /**< Fragment program enabled */
99 #define ATIFRAGSHADER_BIT 0x4000 /**< ATI Fragment shader enabled */
100 #define CLAMPING_BIT 0x8000 /**< Clamp colors to [0,1] */
103 #define _SWRAST_NEW_RASTERMASK (_NEW_BUFFERS| \
115 struct swrast_texture_image
;
119 * Fetch a texel from texture image at given position.
121 typedef void (*FetchTexelFunc
)(const struct swrast_texture_image
*texImage
,
122 GLint col
, GLint row
, GLint img
,
127 * Subclass of gl_texture_image.
128 * We need extra fields/info to keep tracking of mapped texture buffers,
129 * strides and Fetch functions.
131 struct swrast_texture_image
133 struct gl_texture_image Base
;
135 GLboolean _IsPowerOfTwo
; /**< Are all dimensions powers of two? */
137 /** used for mipmap LOD computation */
138 GLfloat WidthScale
, HeightScale
, DepthScale
;
141 * Byte stride between rows in ImageSlices.
143 * For compressed textures, this is the byte stride between one row of
144 * blocks and the next row of blocks.
146 * Only valid while one of the ImageSlices is mapped, and must be the same
147 * between all slices.
151 * When a texture image is mapped for swrast, this array contains pointers
152 * to the beginning of each slice.
154 * For swrast-allocated textures, these pointers will always stay
155 * initialized to point within Buffer.
159 /** Malloc'd texture memory */
162 FetchTexelFunc FetchTexel
;
164 /** For fetching texels from compressed textures */
165 compressed_fetch_func FetchCompressedTexel
;
170 static inline struct swrast_texture_image
*
171 swrast_texture_image(struct gl_texture_image
*img
)
173 return (struct swrast_texture_image
*) img
;
177 static inline const struct swrast_texture_image
*
178 swrast_texture_image_const(const struct gl_texture_image
*img
)
180 return (const struct swrast_texture_image
*) img
;
185 * Subclass of gl_renderbuffer with extra fields needed for software
188 struct swrast_renderbuffer
190 struct gl_renderbuffer Base
;
192 GLubyte
*Buffer
; /**< The malloc'd memory for buffer */
194 /** These fields are only valid while buffer is mapped for rendering */
196 GLint RowStride
; /**< in bytes */
198 /** For span rendering */
204 static inline struct swrast_renderbuffer
*
205 swrast_renderbuffer(struct gl_renderbuffer
*img
)
207 return (struct swrast_renderbuffer
*) img
;
214 * \brief Per-context state that's private to the software rasterizer module.
218 /** Driver interface:
220 struct swrast_device_driver Driver
;
222 /** Configuration mechanisms to make software rasterizer match
223 * characteristics of the hardware rasterizer (if present):
225 GLboolean AllowVertexFog
;
226 GLboolean AllowPixelFog
;
228 /** Derived values, invalidated on statechanges, updated from
229 * _swrast_validate_derived():
231 GLbitfield _RasterMask
;
232 GLfloat _BackfaceSign
; /** +1 or -1 */
233 GLfloat _BackfaceCullSign
; /** +1, 0, or -1 */
234 GLboolean _PreferPixelFog
; /* Compute fog blend factor per fragment? */
235 GLboolean _TextureCombinePrimary
;
236 GLboolean _FogEnabled
;
237 GLboolean _DeferredTexture
;
239 /** List/array of the fragment attributes to interpolate */
240 GLuint _ActiveAttribs
[VARYING_SLOT_MAX
];
241 /** Same info, but as a bitmask of VARYING_BIT_x bits */
242 GLbitfield64 _ActiveAttribMask
;
243 /** Number of fragment attributes to interpolate */
244 GLuint _NumActiveAttribs
;
245 /** Indicates how each attrib is to be interpolated (lines/tris) */
246 GLenum _InterpMode
[VARYING_SLOT_MAX
]; /* GL_FLAT or GL_SMOOTH (for now) */
250 GLuint StippleCounter
; /**< Line stipple counter */
251 GLuint PointLineFacing
;
254 GLenum Primitive
; /* current primitive being drawn (ala glBegin) */
255 GLboolean SpecularVertexAdd
; /**< Add specular/secondary color per vertex */
257 void (*InvalidateState
)( struct gl_context
*ctx
, GLbitfield new_state
);
260 * When the NewState mask intersects these masks, we invalidate the
261 * Point/Line/Triangle function pointers below.
264 GLbitfield InvalidatePointMask
;
265 GLbitfield InvalidateLineMask
;
266 GLbitfield InvalidateTriangleMask
;
270 * Device drivers plug in functions for these callbacks.
271 * Will be called when the GL state change mask intersects the above masks.
274 void (*choose_point
)( struct gl_context
* );
275 void (*choose_line
)( struct gl_context
* );
276 void (*choose_triangle
)( struct gl_context
* );
280 * Current point, line and triangle drawing functions.
283 swrast_point_func Point
;
284 swrast_line_func Line
;
285 swrast_tri_func Triangle
;
289 * Placeholders for when separate specular (or secondary color) is
290 * enabled but texturing is not.
293 swrast_point_func SpecPoint
;
294 swrast_line_func SpecLine
;
295 swrast_tri_func SpecTriangle
;
299 * Typically, we'll allocate a sw_span structure as a local variable
300 * and set its 'array' pointer to point to this object. The reason is
301 * this object is big and causes problems when allocated on the stack
304 SWspanarrays
*SpanArrays
;
305 SWspanarrays
*ZoomedArrays
; /**< For pixel zooming */
308 * Used to buffer N GL_POINTS, instead of rendering one by one.
312 /** Internal hooks, kept up to date by the same mechanism as above.
314 blend_func BlendFunc
;
315 texture_sample_func TextureSample
[MAX_COMBINED_TEXTURE_IMAGE_UNITS
];
317 /** Buffer for saving the sampled texture colors.
318 * Needed for GL_ARB_texture_env_crossbar implementation.
320 GLfloat
*TexelBuffer
;
322 validate_texture_image_func ValidateTextureImage
;
324 /** State used during execution of fragment programs */
325 struct gl_program_machine FragProgMachine
;
327 /** Temporary arrays for stencil operations. To avoid large stack
331 GLubyte
*buf1
, *buf2
, *buf3
, *buf4
;
338 _swrast_validate_derived( struct gl_context
*ctx
);
341 _swrast_update_texture_samplers(struct gl_context
*ctx
);
344 /** Return SWcontext for the given struct gl_context */
345 static inline SWcontext
*
346 SWRAST_CONTEXT(struct gl_context
*ctx
)
348 return (SWcontext
*) ctx
->swrast_context
;
351 /** const version of above */
352 static inline const SWcontext
*
353 CONST_SWRAST_CONTEXT(const struct gl_context
*ctx
)
355 return (const SWcontext
*) ctx
->swrast_context
;
360 * Called prior to framebuffer reading/writing.
361 * For drivers that rely on swrast for fallback rendering, this is the
362 * driver's opportunity to map renderbuffers and textures.
365 swrast_render_start(struct gl_context
*ctx
)
367 SWcontext
*swrast
= SWRAST_CONTEXT(ctx
);
368 if (swrast
->Driver
.SpanRenderStart
)
369 swrast
->Driver
.SpanRenderStart(ctx
);
373 /** Called after framebuffer reading/writing */
375 swrast_render_finish(struct gl_context
*ctx
)
377 SWcontext
*swrast
= SWRAST_CONTEXT(ctx
);
378 if (swrast
->Driver
.SpanRenderFinish
)
379 swrast
->Driver
.SpanRenderFinish(ctx
);
384 _swrast_span_render_start(struct gl_context
*ctx
);
387 _swrast_span_render_finish(struct gl_context
*ctx
);
390 _swrast_map_textures(struct gl_context
*ctx
);
393 _swrast_unmap_textures(struct gl_context
*ctx
);
396 _swrast_teximage_slice_height(struct gl_texture_image
*texImage
);
399 _swrast_map_texture(struct gl_context
*ctx
, struct gl_texture_object
*texObj
);
402 _swrast_unmap_texture(struct gl_context
*ctx
, struct gl_texture_object
*texObj
);
406 _swrast_map_renderbuffers(struct gl_context
*ctx
);
409 _swrast_unmap_renderbuffers(struct gl_context
*ctx
);
413 * Size of an RGBA pixel, in bytes, for given datatype.
415 #define RGBA_PIXEL_SIZE(TYPE) \
416 ((TYPE == GL_UNSIGNED_BYTE) ? 4 * sizeof(GLubyte) : \
417 ((TYPE == GL_UNSIGNED_SHORT) ? 4 * sizeof(GLushort) \
418 : 4 * sizeof(GLfloat)))
423 * Fixed point arithmetic macros
425 #ifndef FIXED_FRAC_BITS
426 #define FIXED_FRAC_BITS 11
429 #define FIXED_SHIFT FIXED_FRAC_BITS
430 #define FIXED_ONE (1 << FIXED_SHIFT)
431 #define FIXED_HALF (1 << (FIXED_SHIFT-1))
432 #define FIXED_FRAC_MASK (FIXED_ONE - 1)
433 #define FIXED_INT_MASK (~FIXED_FRAC_MASK)
434 #define FIXED_EPSILON 1
435 #define FIXED_SCALE ((float) FIXED_ONE)
436 #define FIXED_DBL_SCALE ((double) FIXED_ONE)
437 #define FloatToFixed(X) (IROUND((X) * FIXED_SCALE))
438 #define FixedToDouble(X) ((X) * (1.0 / FIXED_DBL_SCALE))
439 #define IntToFixed(I) ((I) << FIXED_SHIFT)
440 #define FixedToInt(X) ((X) >> FIXED_SHIFT)
441 #define FixedToUns(X) (((unsigned int)(X)) >> FIXED_SHIFT)
442 #define FixedCeil(X) (((X) + FIXED_ONE - FIXED_EPSILON) & FIXED_INT_MASK)
443 #define FixedFloor(X) ((X) & FIXED_INT_MASK)
444 #define FixedToFloat(X) ((X) * (1.0F / FIXED_SCALE))
445 #define PosFloatToFixed(X) FloatToFixed(X)
446 #define SignedFloatToFixed(X) FloatToFixed(X)
451 * XXX these macros are just bandages for now in order to make
452 * CHAN_BITS==32 compile cleanly.
453 * These should probably go elsewhere at some point.
455 #if CHAN_TYPE == GL_FLOAT
456 #define ChanToFixed(X) (X)
457 #define FixedToChan(X) (X)
459 #define ChanToFixed(X) IntToFixed(X)
460 #define FixedToChan(X) FixedToInt(X)
465 * For looping over fragment attributes in the pointe, line
466 * triangle rasterizers.
468 #define ATTRIB_LOOP_BEGIN \
471 for (a = 0; a < swrast->_NumActiveAttribs; a++) { \
472 const GLuint attr = swrast->_ActiveAttribs[a];
474 #define ATTRIB_LOOP_END } }
478 * Return the address of a pixel value in a mapped renderbuffer.
480 static inline GLubyte
*
481 _swrast_pixel_address(struct gl_renderbuffer
*rb
, GLint x
, GLint y
)
483 struct swrast_renderbuffer
*srb
= swrast_renderbuffer(rb
);
484 const GLint bpp
= _mesa_get_format_bytes(rb
->Format
);
485 const GLint rowStride
= srb
->RowStride
;
488 /* NOTE: using <= only because of s_tritemp.h which gets a pixel
489 * address but doesn't necessarily access it.
491 assert(x
<= (GLint
) rb
->Width
);
492 assert(y
<= (GLint
) rb
->Height
);
494 return (GLubyte
*) srb
->Map
+ y
* rowStride
+ x
* bpp
;