s_span.h

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/*
 * Mesa 3-D graphics library
 * Version:  6.5
 *
 * Copyright (C) 1999-2005  Brian Paul   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"


#define SPAN_RGBA       0x01  
#define SPAN_INDEX      0x02  
#define SPAN_Z          0x04  
#define SPAN_FLAT       0x08  
#define SPAN_XY         0x10  
#define SPAN_MASK       0x20  
#define SPAN_LAMBDA     0x40  
#define SPAN_COVERAGE   0x80  


typedef struct sw_span_arrays
{
   /* XXX someday look at transposing first two indexes for better memory
    * access pattern.
    */
   GLfloat attribs[FRAG_ATTRIB_MAX][MAX_WIDTH][4];

   GLubyte mask[MAX_WIDTH];

   GLenum ChanType; 
   GLubyte rgba8[MAX_WIDTH][4];
   GLushort rgba16[MAX_WIDTH][4];
   GLchan (*rgba)[4];  
   GLint   x[MAX_WIDTH];  
   GLint   y[MAX_WIDTH];  
   GLuint  z[MAX_WIDTH];  
   GLuint  index[MAX_WIDTH];  
   GLfloat lambda[MAX_TEXTURE_COORD_UNITS][MAX_WIDTH]; 
   GLfloat coverage[MAX_WIDTH];  
} SWspanarrays;


typedef struct sw_span
{
   GLint x, y;

   GLuint end;

   GLboolean writeAll;

   GLenum primitive;

   GLuint facing;

   GLbitfield interpMask;

   GLfloat attrStart[FRAG_ATTRIB_MAX][4];   
   GLfloat attrStepX[FRAG_ATTRIB_MAX][4];   
   GLfloat attrStepY[FRAG_ATTRIB_MAX][4];   
   /* 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;    
   GLfixed intTex[2], intTexStep[2];  
   GLbitfield arrayMask;

   GLbitfield arrayAttribs;

   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).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_index_span( GLcontext *ctx, SWspan *span);


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