2 * Mesa 3-D graphics library
5 * Copyright (C) 1999-2005 Brian Paul All Rights Reserved.
7 * Permission is hereby granted, free of charge, to any person obtaining a
8 * copy of this software and associated documentation files (the "Software"),
9 * to deal in the Software without restriction, including without limitation
10 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
11 * and/or sell copies of the Software, and to permit persons to whom the
12 * Software is furnished to do so, subject to the following conditions:
14 * The above copyright notice and this permission notice shall be included
15 * in all copies or substantial portions of the Software.
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
18 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
21 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
22 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
35 * Special bitflags to describe span data.
37 * In general, the point/line/triangle functions interpolate/emit the
38 * attributes specified by swrast->_ActiveAttribs (i.e. FRAT_BIT_* values).
39 * Some things don't fit into that, though, so we have these flags.
42 #define SPAN_RGBA 0x01 /**< interpMask and arrayMask */
43 #define SPAN_INDEX 0x02 /**< interpMask and arrayMask */
44 #define SPAN_Z 0x04 /**< interpMask and arrayMask */
45 #define SPAN_FLAT 0x08 /**< interpMask: flat shading? */
46 #define SPAN_XY 0x10 /**< array.x[], y[] valid? */
47 #define SPAN_MASK 0x20 /**< was array.mask[] filled in by caller? */
48 #define SPAN_LAMBDA 0x40 /**< array.lambda[] valid? */
49 #define SPAN_COVERAGE 0x80 /**< array.coverage[] valid? */
55 * \brief Arrays of fragment values.
57 * These will either be computed from the span x/xStep values or
58 * filled in by glDraw/CopyPixels, etc.
59 * These arrays are separated out of sw_span to conserve memory.
61 typedef struct sw_span_arrays
63 /** Per-fragment attributes (indexed by FRAG_ATTRIB_* tokens) */
64 /* XXX someday look at transposing first two indexes for better memory
67 GLfloat attribs
[FRAG_ATTRIB_MAX
][MAX_WIDTH
][4];
69 /** This mask indicates which fragments are alive or culled */
70 GLubyte mask
[MAX_WIDTH
];
72 GLenum ChanType
; /**< Color channel type, GL_UNSIGNED_BYTE, GL_FLOAT */
74 /** Attribute arrays that don't fit into attribs[] array above */
76 GLubyte rgba8
[MAX_WIDTH
][4];
77 GLushort rgba16
[MAX_WIDTH
][4];
78 GLchan (*rgba
)[4]; /** either == rgba8 or rgba16 */
79 GLint x
[MAX_WIDTH
]; /**< fragment X coords */
80 GLint y
[MAX_WIDTH
]; /**< fragment Y coords */
81 GLuint z
[MAX_WIDTH
]; /**< fragment Z coords */
82 GLuint index
[MAX_WIDTH
]; /**< Color indexes */
83 GLfloat lambda
[MAX_TEXTURE_COORD_UNITS
][MAX_WIDTH
]; /**< Texture LOD */
84 GLfloat coverage
[MAX_WIDTH
]; /**< Fragment coverage for AA/smoothing */
90 * The SWspan structure describes the colors, Z, fogcoord, texcoords,
91 * etc for either a horizontal run or an array of independent pixels.
92 * We can either specify a base/step to indicate interpolated values, or
93 * fill in explicit arrays of values. The interpMask and arrayMask bitfields
94 * indicate which attributes are active interpolants or arrays, respectively.
96 * It would be interesting to experiment with multiprocessor rasterization
97 * with this structure. The triangle rasterizer could simply emit a
98 * stream of these structures which would be consumed by one or more
99 * span-processing threads which could run in parallel.
101 typedef struct sw_span
103 /** Coord of first fragment in horizontal span/run */
106 /** Number of fragments in the span */
109 /** This flag indicates that mask[] array is effectively filled with ones */
112 /** either GL_POLYGON, GL_LINE, GL_POLYGON, GL_BITMAP */
115 /** 0 = front-facing span, 1 = back-facing span (for two-sided stencil) */
119 * This bitmask (of \link SpanFlags SPAN_* flags\endlink) indicates
120 * which of the attrStart/StepX/StepY variables are relevant.
122 GLbitfield interpMask
;
124 /** Fragment attribute interpolants */
125 GLfloat attrStart
[FRAG_ATTRIB_MAX
][4]; /**< initial value */
126 GLfloat attrStepX
[FRAG_ATTRIB_MAX
][4]; /**< dvalue/dx */
127 GLfloat attrStepY
[FRAG_ATTRIB_MAX
][4]; /**< dvalue/dy */
129 /* XXX the rest of these will go away eventually... */
131 /* For horizontal spans, step is the partial derivative wrt X.
132 * For lines, step is the delta from one fragment to the next.
134 GLfixed red
, redStep
;
135 GLfixed green
, greenStep
;
136 GLfixed blue
, blueStep
;
137 GLfixed alpha
, alphaStep
;
138 GLfixed index
, indexStep
;
139 GLfixed z
, zStep
; /**< XXX z should probably be GLuint */
140 GLfixed intTex
[2], intTexStep
[2]; /**< (s,t) for unit[0] only */
143 * This bitmask (of \link SpanFlags SPAN_* flags\endlink) indicates
144 * which of the fragment arrays in the span_arrays struct are relevant.
146 GLbitfield arrayMask
;
148 GLbitfield arrayAttribs
;
151 * We store the arrays of fragment values in a separate struct so
152 * that we can allocate sw_span structs on the stack without using
153 * a lot of memory. The span_arrays struct is about 1.4MB while the
154 * sw_span struct is only about 512 bytes.
161 #define INIT_SPAN(S, PRIMITIVE) \
163 (S).primitive = (PRIMITIVE); \
164 (S).interpMask = 0x0; \
165 (S).arrayMask = 0x0; \
166 (S).arrayAttribs = 0x0; \
169 (S).array = SWRAST_CONTEXT(ctx)->SpanArrays; \
175 _swrast_span_default_attribs(GLcontext
*ctx
, SWspan
*span
);
178 _swrast_span_interpolate_z( const GLcontext
*ctx
, SWspan
*span
);
181 _swrast_compute_lambda(GLfloat dsdx
, GLfloat dsdy
, GLfloat dtdx
, GLfloat dtdy
,
182 GLfloat dqdx
, GLfloat dqdy
, GLfloat texW
, GLfloat texH
,
183 GLfloat s
, GLfloat t
, GLfloat q
, GLfloat invQ
);
186 _swrast_write_index_span( GLcontext
*ctx
, SWspan
*span
);
190 _swrast_write_rgba_span( GLcontext
*ctx
, SWspan
*span
);
194 _swrast_read_rgba_span(GLcontext
*ctx
, struct gl_renderbuffer
*rb
,
195 GLuint n
, GLint x
, GLint y
, GLenum type
, GLvoid
*rgba
);
198 _swrast_read_index_span( GLcontext
*ctx
, struct gl_renderbuffer
*rb
,
199 GLuint n
, GLint x
, GLint y
, GLuint indx
[] );
202 _swrast_get_values(GLcontext
*ctx
, struct gl_renderbuffer
*rb
,
203 GLuint count
, const GLint x
[], const GLint y
[],
204 void *values
, GLuint valueSize
);
207 _swrast_put_row(GLcontext
*ctx
, struct gl_renderbuffer
*rb
,
208 GLuint count
, GLint x
, GLint y
,
209 const GLvoid
*values
, GLuint valueSize
);
212 _swrast_get_row(GLcontext
*ctx
, struct gl_renderbuffer
*rb
,
213 GLuint count
, GLint x
, GLint y
,
214 GLvoid
*values
, GLuint valueSize
);
218 _swrast_get_dest_rgba(GLcontext
*ctx
, struct gl_renderbuffer
*rb
,