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/*
* Mesa 3-D graphics library
* Version: 7.5
*
* Copyright (C) 1999-2008 Brian Paul All Rights Reserved.
* Copyright (C) 2009 VMware, Inc. All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#ifndef S_SPAN_H
#define S_SPAN_H
#include "swrast.h"
/**
* \defgroup SpanFlags
* Special bitflags to describe span data.
*
* In general, the point/line/triangle functions interpolate/emit the
* attributes specified by swrast->_ActiveAttribs (i.e. FRAT_BIT_* values).
* Some things don't fit into that, though, so we have these flags.
*/
/*@{*/
#define SPAN_RGBA 0x01 /**< interpMask and arrayMask */
#define SPAN_INDEX 0x02 /**< interpMask and arrayMask */
#define SPAN_Z 0x04 /**< interpMask and arrayMask */
#define SPAN_FLAT 0x08 /**< interpMask: flat shading? */
#define SPAN_XY 0x10 /**< array.x[], y[] valid? */
#define SPAN_MASK 0x20 /**< was array.mask[] filled in by caller? */
#define SPAN_LAMBDA 0x40 /**< array.lambda[] valid? */
#define SPAN_COVERAGE 0x80 /**< array.coverage[] valid? */
/*@}*/
/**
* \sw_span_arrays
* \brief Arrays of fragment values.
*
* These will either be computed from the span x/xStep values or
* filled in by glDraw/CopyPixels, etc.
* These arrays are separated out of sw_span to conserve memory.
*/
typedef struct sw_span_arrays
{
/** Per-fragment attributes (indexed by FRAG_ATTRIB_* tokens) */
/* XXX someday look at transposing first two indexes for better memory
* access pattern.
*/
GLfloat attribs[FRAG_ATTRIB_MAX][MAX_WIDTH][4];
/** This mask indicates which fragments are alive or culled */
GLubyte mask[MAX_WIDTH];
GLenum ChanType; /**< Color channel type, GL_UNSIGNED_BYTE, GL_FLOAT */
/** Attribute arrays that don't fit into attribs[] array above */
/*@{*/
GLubyte rgba8[MAX_WIDTH][4];
GLushort rgba16[MAX_WIDTH][4];
GLchan (*rgba)[4]; /** either == rgba8 or rgba16 */
GLint x[MAX_WIDTH]; /**< fragment X coords */
GLint y[MAX_WIDTH]; /**< fragment Y coords */
GLuint z[MAX_WIDTH]; /**< fragment Z coords */
GLuint index[MAX_WIDTH]; /**< Color indexes */
GLfloat lambda[MAX_TEXTURE_COORD_UNITS][MAX_WIDTH]; /**< Texture LOD */
GLfloat coverage[MAX_WIDTH]; /**< Fragment coverage for AA/smoothing */
/*@}*/
} SWspanarrays;
/**
* The SWspan structure describes the colors, Z, fogcoord, texcoords,
* etc for either a horizontal run or an array of independent pixels.
* We can either specify a base/step to indicate interpolated values, or
* fill in explicit arrays of values. The interpMask and arrayMask bitfields
* indicate which attributes are active interpolants or arrays, respectively.
*
* It would be interesting to experiment with multiprocessor rasterization
* with this structure. The triangle rasterizer could simply emit a
* stream of these structures which would be consumed by one or more
* span-processing threads which could run in parallel.
*/
typedef struct sw_span
{
/** Coord of first fragment in horizontal span/run */
GLint x, y;
/** Number of fragments in the span */
GLuint end;
/** for clipping left edge of spans */
GLuint leftClip;
/** This flag indicates that mask[] array is effectively filled with ones */
GLboolean writeAll;
/** either GL_POLYGON, GL_LINE, GL_POLYGON, GL_BITMAP */
GLenum primitive;
/** 0 = front-facing span, 1 = back-facing span (for two-sided stencil) */
GLuint facing;
/**
* This bitmask (of \link SpanFlags SPAN_* flags\endlink) indicates
* which of the attrStart/StepX/StepY variables are relevant.
*/
GLbitfield interpMask;
/** Fragment attribute interpolants */
GLfloat attrStart[FRAG_ATTRIB_MAX][4]; /**< initial value */
GLfloat attrStepX[FRAG_ATTRIB_MAX][4]; /**< dvalue/dx */
GLfloat attrStepY[FRAG_ATTRIB_MAX][4]; /**< dvalue/dy */
/* XXX the rest of these will go away eventually... */
/* For horizontal spans, step is the partial derivative wrt X.
* For lines, step is the delta from one fragment to the next.
*/
GLfixed red, redStep;
GLfixed green, greenStep;
GLfixed blue, blueStep;
GLfixed alpha, alphaStep;
GLfixed index, indexStep;
GLfixed z, zStep; /**< XXX z should probably be GLuint */
GLfixed intTex[2], intTexStep[2]; /**< (s,t) for unit[0] only */
/**
* This bitmask (of \link SpanFlags SPAN_* flags\endlink) indicates
* which of the fragment arrays in the span_arrays struct are relevant.
*/
GLbitfield arrayMask;
GLbitfield arrayAttribs;
/**
* We store the arrays of fragment values in a separate struct so
* that we can allocate sw_span structs on the stack without using
* a lot of memory. The span_arrays struct is about 1.4MB while the
* sw_span struct is only about 512 bytes.
*/
SWspanarrays *array;
} SWspan;
#define INIT_SPAN(S, PRIMITIVE) \
do { \
(S).primitive = (PRIMITIVE); \
(S).interpMask = 0x0; \
(S).arrayMask = 0x0; \
(S).arrayAttribs = 0x0; \
(S).end = 0; \
(S).leftClip = 0; \
(S).facing = 0; \
(S).array = SWRAST_CONTEXT(ctx)->SpanArrays; \
} while (0)
extern void
_swrast_span_default_attribs(GLcontext *ctx, SWspan *span);
extern void
_swrast_span_interpolate_z( const GLcontext *ctx, SWspan *span );
extern GLfloat
_swrast_compute_lambda(GLfloat dsdx, GLfloat dsdy, GLfloat dtdx, GLfloat dtdy,
GLfloat dqdx, GLfloat dqdy, GLfloat texW, GLfloat texH,
GLfloat s, GLfloat t, GLfloat q, GLfloat invQ);
extern void
_swrast_write_rgba_span( GLcontext *ctx, SWspan *span);
extern void
_swrast_read_rgba_span(GLcontext *ctx, struct gl_renderbuffer *rb,
GLuint n, GLint x, GLint y, GLenum type, GLvoid *rgba);
extern void
_swrast_read_index_span( GLcontext *ctx, struct gl_renderbuffer *rb,
GLuint n, GLint x, GLint y, GLuint indx[] );
extern void
_swrast_get_values(GLcontext *ctx, struct gl_renderbuffer *rb,
GLuint count, const GLint x[], const GLint y[],
void *values, GLuint valueSize);
extern void
_swrast_put_row(GLcontext *ctx, struct gl_renderbuffer *rb,
GLuint count, GLint x, GLint y,
const GLvoid *values, GLuint valueSize);
extern void
_swrast_get_row(GLcontext *ctx, struct gl_renderbuffer *rb,
GLuint count, GLint x, GLint y,
GLvoid *values, GLuint valueSize);
extern void *
_swrast_get_dest_rgba(GLcontext *ctx, struct gl_renderbuffer *rb,
SWspan *span);
#endif
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