s_span.h File Reference

#include "swrast.h"

Data Structures
struct	sw_span_arrays
	More...
struct	sw_span
	The SWspan structure describes the colors, Z, fogcoord, texcoords, etc for either a horizontal run or an array of independent pixels. More...
Defines
#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?
#define	INIT_SPAN(S, PRIMITIVE)
Typedefs
typedef struct sw_span_arrays	SWspanarrays
typedef struct sw_span	SWspan
Functions
void	_swrast_span_default_attribs (GLcontext *ctx, SWspan *span)
	Set default fragment attributes for the span using the current raster values.
void	_swrast_span_interpolate_z (const GLcontext *ctx, SWspan *span)
	Fill in the span.zArray array from the span->z, zStep values.
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)
	Compute mipmap LOD from partial derivatives.
void	_swrast_write_index_span (GLcontext *ctx, SWspan *span)
	Apply all the per-fragment opertions to a span of color index fragments and write them to the enabled color drawbuffers.
void	_swrast_write_rgba_span (GLcontext *ctx, SWspan *span)
	Apply all the per-fragment operations to a span.
void	_swrast_read_rgba_span (GLcontext *ctx, struct gl_renderbuffer *rb, GLuint n, GLint x, GLint y, GLenum type, GLvoid *rgba)
	Read RGBA pixels from a renderbuffer.
void	_swrast_read_index_span (GLcontext *ctx, struct gl_renderbuffer *rb, GLuint n, GLint x, GLint y, GLuint indx[])
	Read CI pixels from a renderbuffer.
void	_swrast_get_values (GLcontext *ctx, struct gl_renderbuffer *rb, GLuint count, const GLint x[], const GLint y[], void *values, GLuint valueSize)
	Wrapper for gl_renderbuffer::GetValues() which does clipping to avoid reading values outside the buffer bounds.
void	_swrast_put_row (GLcontext *ctx, struct gl_renderbuffer *rb, GLuint count, GLint x, GLint y, const GLvoid *values, GLuint valueSize)
	Wrapper for gl_renderbuffer::PutRow() which does clipping.
void	_swrast_get_row (GLcontext *ctx, struct gl_renderbuffer *rb, GLuint count, GLint x, GLint y, GLvoid *values, GLuint valueSize)
	Wrapper for gl_renderbuffer::GetRow() which does clipping.
void *	_swrast_get_dest_rgba (GLcontext *ctx, struct gl_renderbuffer *rb, SWspan *span)
	Get RGBA pixels from the given renderbuffer.

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Define Documentation

#define INIT_SPAN	(	S,
		PRIMITIVE		)

Value:

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)

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Typedef Documentation

typedef struct sw_span SWspan

typedef struct sw_span_arrays SWspanarrays

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Function Documentation

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
	)

Compute mipmap LOD from partial derivatives.

This the ideal solution, as given in the OpenGL spec.

void* _swrast_get_dest_rgba	(	GLcontext *	ctx,
		struct gl_renderbuffer *	rb,
		SWspan *	span
	)

Get RGBA pixels from the given renderbuffer.

Put the pixel colors into the span's specular color arrays. The specular color arrays should no longer be needed by time this function is called. Used by blending, logicop and masking functions.

Returns:

pointer to the colors we read.

void _swrast_get_row	(	GLcontext *	ctx,
		struct gl_renderbuffer *	rb,
		GLuint	count,
		GLint	x,
		GLint	y,
		GLvoid *	values,
		GLuint	valueSize
	)

Wrapper for gl_renderbuffer::GetRow() which does clipping.

Parameters:

valueSize

size of each value (pixel) in bytes

void _swrast_get_values	(	GLcontext *	ctx,
		struct gl_renderbuffer *	rb,
		GLuint	count,
		const GLint	x[],
		const GLint	y[],
		void *	values,
		GLuint	valueSize
	)

Wrapper for gl_renderbuffer::GetValues() which does clipping to avoid reading values outside the buffer bounds.

We can use this for reading any format/type of renderbuffer.

Parameters:

valueSize

is the size in bytes of each value (pixel) put into the values array.

void _swrast_put_row	(	GLcontext *	ctx,
		struct gl_renderbuffer *	rb,
		GLuint	count,
		GLint	x,
		GLint	y,
		const GLvoid *	values,
		GLuint	valueSize
	)

Wrapper for gl_renderbuffer::PutRow() which does clipping.

Parameters:

valueSize

size of each value (pixel) in bytes

void _swrast_read_index_span	(	GLcontext *	ctx,
		struct gl_renderbuffer *	rb,
		GLuint	n,
		GLint	x,
		GLint	y,
		GLuint	index[]
	)

Read CI pixels from a renderbuffer.

Clipping will be done to prevent reading ouside the buffer's boundaries.

void _swrast_read_rgba_span	(	GLcontext *	ctx,
		struct gl_renderbuffer *	rb,
		GLuint	n,
		GLint	x,
		GLint	y,
		GLenum	dstType,
		GLvoid *	rgba
	)

Read RGBA pixels from a renderbuffer.

Clipping will be done to prevent reading ouside the buffer's boundaries.

Parameters:

	dstType	datatype for returned colors
	rgba	the returned colors

void _swrast_span_default_attribs	(	GLcontext *	ctx,
		SWspan *	span
	)

Set default fragment attributes for the span using the current raster values.

Used prior to glDraw/CopyPixels and glBitmap.

void _swrast_span_interpolate_z	(	const GLcontext *	ctx,
		SWspan *	span
	)

Fill in the span.zArray array from the span->z, zStep values.

void _swrast_write_index_span	(	GLcontext *	ctx,
		SWspan *	span
	)

Apply all the per-fragment opertions to a span of color index fragments and write them to the enabled color drawbuffers.

The 'span' parameter can be considered to be const. Note that span->interpMask and span->arrayMask may be changed but will be restored to their original values before returning.

void _swrast_write_rgba_span	(	GLcontext *	ctx,
		SWspan *	span
	)

Apply all the per-fragment operations to a span.

This now includes texturing (_swrast_write_texture_span() is history). This function may modify any of the array values in the span. span->interpMask and span->arrayMask may be changed but will be restored to their original values before returning.

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