2 * Mesa 3-D graphics library
5 * Copyright (C) 1999-2007 Brian Paul All Rights Reserved.
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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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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"
52 typedef void (*texture_sample_func
)(struct gl_context
*ctx
,
53 const struct gl_texture_object
*tObj
,
54 GLuint n
, const GLfloat texcoords
[][4],
55 const GLfloat lambda
[], GLfloat rgba
[][4]);
57 typedef void (_ASMAPIP blend_func
)( struct gl_context
*ctx
, GLuint n
,
59 GLvoid
*src
, const GLvoid
*dst
,
62 typedef void (*swrast_point_func
)( struct gl_context
*ctx
, const SWvertex
*);
64 typedef void (*swrast_line_func
)( struct gl_context
*ctx
,
65 const SWvertex
*, const SWvertex
*);
67 typedef void (*swrast_tri_func
)( struct gl_context
*ctx
, const SWvertex
*,
68 const SWvertex
*, const SWvertex
*);
71 typedef void (*validate_texture_image_func
)(struct gl_context
*ctx
,
72 struct gl_texture_object
*texObj
,
73 GLuint face
, GLuint level
);
78 * Bitmasks to indicate which rasterization options are enabled
82 #define ALPHATEST_BIT 0x001 /**< Alpha-test pixels */
83 #define BLEND_BIT 0x002 /**< Blend pixels */
84 #define DEPTH_BIT 0x004 /**< Depth-test pixels */
85 #define FOG_BIT 0x008 /**< Fog pixels */
86 #define LOGIC_OP_BIT 0x010 /**< Apply logic op in software */
87 #define CLIP_BIT 0x020 /**< Scissor or window clip pixels */
88 #define STENCIL_BIT 0x040 /**< Stencil pixels */
89 #define MASKING_BIT 0x080 /**< Do glColorMask or glIndexMask */
90 #define MULTI_DRAW_BIT 0x400 /**< Write to more than one color- */
91 /**< buffer or no buffers. */
92 #define TEXTURE_BIT 0x1000 /**< Texturing really enabled */
93 #define CLAMPING_BIT 0x8000 /**< Clamp colors to [0,1] */
96 #define _SWRAST_NEW_RASTERMASK (_NEW_BUFFERS| \
107 struct swrast_texture_image
;
111 * Fetch a texel from texture image at given position.
113 typedef void (*FetchTexelFunc
)(const struct swrast_texture_image
*texImage
,
114 GLint col
, GLint row
, GLint img
,
119 * Subclass of gl_texture_image.
120 * We need extra fields/info to keep tracking of mapped texture buffers,
121 * strides and Fetch functions.
123 struct swrast_texture_image
125 struct gl_texture_image Base
;
127 GLboolean _IsPowerOfTwo
; /**< Are all dimensions powers of two? */
129 /** used for mipmap LOD computation */
130 GLfloat WidthScale
, HeightScale
, DepthScale
;
132 /** These fields only valid when texture memory is mapped */
133 GLint RowStride
; /**< Padded width in units of texels */
134 GLuint
*ImageOffsets
; /**< if 3D texture: array [Depth] of offsets to
135 each 2D slice in 'Data', in texels */
136 GLubyte
*Map
; /**< Pointer to mapped image memory */
138 /** Malloc'd texture memory */
141 FetchTexelFunc FetchTexel
;
146 static inline struct swrast_texture_image
*
147 swrast_texture_image(struct gl_texture_image
*img
)
149 return (struct swrast_texture_image
*) img
;
153 static inline const struct swrast_texture_image
*
154 swrast_texture_image_const(const struct gl_texture_image
*img
)
156 return (const struct swrast_texture_image
*) img
;
161 * Subclass of gl_renderbuffer with extra fields needed for software
164 struct swrast_renderbuffer
166 struct gl_renderbuffer Base
;
168 GLubyte
*Buffer
; /**< The malloc'd memory for buffer */
170 /** These fields are only valid while buffer is mapped for rendering */
172 GLint RowStride
; /**< in bytes */
174 /** For span rendering */
180 static inline struct swrast_renderbuffer
*
181 swrast_renderbuffer(struct gl_renderbuffer
*img
)
183 return (struct swrast_renderbuffer
*) img
;
190 * \brief Per-context state that's private to the software rasterizer module.
194 /** Driver interface:
196 struct swrast_device_driver Driver
;
198 /** Configuration mechanisms to make software rasterizer match
199 * characteristics of the hardware rasterizer (if present):
201 GLboolean AllowVertexFog
;
202 GLboolean AllowPixelFog
;
204 /** Derived values, invalidated on statechanges, updated from
205 * _swrast_validate_derived():
207 GLbitfield _RasterMask
;
208 GLfloat _BackfaceSign
; /** +1 or -1 */
209 GLfloat _BackfaceCullSign
; /** +1, 0, or -1 */
210 GLboolean _PreferPixelFog
; /* Compute fog blend factor per fragment? */
211 GLboolean _TextureCombinePrimary
;
212 GLboolean _FogEnabled
;
213 GLboolean _DeferredTexture
;
215 /** List/array of the fragment attributes to interpolate */
216 GLuint _ActiveAttribs
[FRAG_ATTRIB_MAX
];
217 /** Same info, but as a bitmask of FRAG_BIT_x bits */
218 GLbitfield64 _ActiveAttribMask
;
219 /** Number of fragment attributes to interpolate */
220 GLuint _NumActiveAttribs
;
221 /** Indicates how each attrib is to be interpolated (lines/tris) */
222 GLenum _InterpMode
[FRAG_ATTRIB_MAX
]; /* GL_FLAT or GL_SMOOTH (for now) */
226 GLuint StippleCounter
; /**< Line stipple counter */
229 GLenum Primitive
; /* current primitive being drawn (ala glBegin) */
230 GLboolean SpecularVertexAdd
; /**< Add specular/secondary color per vertex */
232 void (*InvalidateState
)( struct gl_context
*ctx
, GLbitfield new_state
);
235 * When the NewState mask intersects these masks, we invalidate the
236 * Point/Line/Triangle function pointers below.
239 GLbitfield InvalidatePointMask
;
240 GLbitfield InvalidateLineMask
;
241 GLbitfield InvalidateTriangleMask
;
245 * Device drivers plug in functions for these callbacks.
246 * Will be called when the GL state change mask intersects the above masks.
249 void (*choose_point
)( struct gl_context
* );
250 void (*choose_line
)( struct gl_context
* );
251 void (*choose_triangle
)( struct gl_context
* );
255 * Current point, line and triangle drawing functions.
258 swrast_point_func Point
;
259 swrast_line_func Line
;
260 swrast_tri_func Triangle
;
264 * Placeholders for when separate specular (or secondary color) is
265 * enabled but texturing is not.
268 swrast_point_func SpecPoint
;
269 swrast_line_func SpecLine
;
270 swrast_tri_func SpecTriangle
;
274 * Typically, we'll allocate a sw_span structure as a local variable
275 * and set its 'array' pointer to point to this object. The reason is
276 * this object is big and causes problems when allocated on the stack
279 SWspanarrays
*SpanArrays
;
280 SWspanarrays
*ZoomedArrays
; /**< For pixel zooming */
283 * Used to buffer N GL_POINTS, instead of rendering one by one.
287 /** Internal hooks, kept up to date by the same mechanism as above.
289 blend_func BlendFunc
;
290 texture_sample_func TextureSample
;
292 /** Buffer for saving the sampled texture colors.
293 * Needed for GL_ARB_texture_env_crossbar implementation.
295 GLfloat
*TexelBuffer
;
297 validate_texture_image_func ValidateTextureImage
;
303 _swrast_validate_derived( struct gl_context
*ctx
);
306 _swrast_update_texture_samplers(struct gl_context
*ctx
);
309 /** Return SWcontext for the given struct gl_context */
310 static inline SWcontext
*
311 SWRAST_CONTEXT(struct gl_context
*ctx
)
313 return (SWcontext
*) ctx
->swrast_context
;
316 /** const version of above */
317 static inline const SWcontext
*
318 CONST_SWRAST_CONTEXT(const struct gl_context
*ctx
)
320 return (const SWcontext
*) ctx
->swrast_context
;
325 * Called prior to framebuffer reading/writing.
326 * For drivers that rely on swrast for fallback rendering, this is the
327 * driver's opportunity to map renderbuffers and textures.
330 swrast_render_start(struct gl_context
*ctx
)
332 SWcontext
*swrast
= SWRAST_CONTEXT(ctx
);
333 if (swrast
->Driver
.SpanRenderStart
)
334 swrast
->Driver
.SpanRenderStart(ctx
);
338 /** Called after framebuffer reading/writing */
340 swrast_render_finish(struct gl_context
*ctx
)
342 SWcontext
*swrast
= SWRAST_CONTEXT(ctx
);
343 if (swrast
->Driver
.SpanRenderFinish
)
344 swrast
->Driver
.SpanRenderFinish(ctx
);
349 _swrast_span_render_start(struct gl_context
*ctx
);
352 _swrast_span_render_finish(struct gl_context
*ctx
);
355 _swrast_map_textures(struct gl_context
*ctx
);
358 _swrast_unmap_textures(struct gl_context
*ctx
);
361 _swrast_map_texture(struct gl_context
*ctx
, struct gl_texture_object
*texObj
);
364 _swrast_unmap_texture(struct gl_context
*ctx
, struct gl_texture_object
*texObj
);
368 _swrast_map_renderbuffers(struct gl_context
*ctx
);
371 _swrast_unmap_renderbuffers(struct gl_context
*ctx
);
375 * Size of an RGBA pixel, in bytes, for given datatype.
377 #define RGBA_PIXEL_SIZE(TYPE) \
378 ((TYPE == GL_UNSIGNED_BYTE) ? 4 * sizeof(GLubyte) : \
379 ((TYPE == GL_UNSIGNED_SHORT) ? 4 * sizeof(GLushort) \
380 : 4 * sizeof(GLfloat)))
385 * Fixed point arithmetic macros
387 #ifndef FIXED_FRAC_BITS
388 #define FIXED_FRAC_BITS 11
391 #define FIXED_SHIFT FIXED_FRAC_BITS
392 #define FIXED_ONE (1 << FIXED_SHIFT)
393 #define FIXED_HALF (1 << (FIXED_SHIFT-1))
394 #define FIXED_FRAC_MASK (FIXED_ONE - 1)
395 #define FIXED_INT_MASK (~FIXED_FRAC_MASK)
396 #define FIXED_EPSILON 1
397 #define FIXED_SCALE ((float) FIXED_ONE)
398 #define FIXED_DBL_SCALE ((double) FIXED_ONE)
399 #define FloatToFixed(X) (IROUND((X) * FIXED_SCALE))
400 #define FixedToDouble(X) ((X) * (1.0 / FIXED_DBL_SCALE))
401 #define IntToFixed(I) ((I) << FIXED_SHIFT)
402 #define FixedToInt(X) ((X) >> FIXED_SHIFT)
403 #define FixedToUns(X) (((unsigned int)(X)) >> FIXED_SHIFT)
404 #define FixedCeil(X) (((X) + FIXED_ONE - FIXED_EPSILON) & FIXED_INT_MASK)
405 #define FixedFloor(X) ((X) & FIXED_INT_MASK)
406 #define FixedToFloat(X) ((X) * (1.0F / FIXED_SCALE))
407 #define PosFloatToFixed(X) FloatToFixed(X)
408 #define SignedFloatToFixed(X) FloatToFixed(X)
413 * XXX these macros are just bandages for now in order to make
414 * CHAN_BITS==32 compile cleanly.
415 * These should probably go elsewhere at some point.
417 #if CHAN_TYPE == GL_FLOAT
418 #define ChanToFixed(X) (X)
419 #define FixedToChan(X) (X)
421 #define ChanToFixed(X) IntToFixed(X)
422 #define FixedToChan(X) FixedToInt(X)
427 * For looping over fragment attributes in the pointe, line
428 * triangle rasterizers.
430 #define ATTRIB_LOOP_BEGIN \
433 for (a = 0; a < swrast->_NumActiveAttribs; a++) { \
434 const GLuint attr = swrast->_ActiveAttribs[a];
436 #define ATTRIB_LOOP_END } }
440 * Return the address of a pixel value in a mapped renderbuffer.
442 static inline GLubyte
*
443 _swrast_pixel_address(struct gl_renderbuffer
*rb
, GLint x
, GLint y
)
445 struct swrast_renderbuffer
*srb
= swrast_renderbuffer(rb
);
446 const GLint bpp
= _mesa_get_format_bytes(rb
->Format
);
447 const GLint rowStride
= srb
->RowStride
;
450 /* NOTE: using <= only because of s_tritemp.h which gets a pixel
451 * address but doesn't necessarily access it.
453 assert(x
<= (GLint
) rb
->Width
);
454 assert(y
<= (GLint
) rb
->Height
);
456 return (GLubyte
*) srb
->Map
+ y
* rowStride
+ x
* bpp
;