s_stencil.c File Reference

#include "main/glheader.h"
#include "main/context.h"
#include "main/imports.h"
#include "s_context.h"
#include "s_depth.h"
#include "s_stencil.h"
#include "s_span.h"

Defines
#define	STENCIL_ADDRESS(X, Y)   (stencilStart + (Y) * stride + (X))
Functions
static void	apply_stencil_op (const GLcontext *ctx, GLenum oper, GLuint face, GLuint n, GLstencil stencil[], const GLubyte mask[])
	Apply the given stencil operator to the array of stencil values.
static GLboolean	do_stencil_test (GLcontext *ctx, GLuint face, GLuint n, GLstencil stencil[], GLubyte mask[])
	Apply stencil test to an array of stencil values (before depth buffering).
static INLINE void	compute_pass_fail_masks (GLuint n, const GLubyte origMask[], const GLubyte newMask[], GLubyte passMask[], GLubyte failMask[])
	Compute the zpass/zfail masks by comparing the pre- and post-depth test masks.
static GLboolean	stencil_and_ztest_span (GLcontext *ctx, SWspan *span, GLuint face)
	Apply stencil and depth testing to the span of pixels.
static void	apply_stencil_op_to_pixels (GLcontext *ctx, GLuint n, const GLint x[], const GLint y[], GLenum oper, GLuint face, const GLubyte mask[])
	Apply the given stencil operator for each pixel in the array whose mask flag is set.
static GLboolean	stencil_test_pixels (GLcontext *ctx, GLuint face, GLuint n, const GLint x[], const GLint y[], GLubyte mask[])
	Apply stencil test to an array of pixels before depth buffering.
static GLboolean	stencil_and_ztest_pixels (GLcontext *ctx, SWspan *span, GLuint face)
	Apply stencil and depth testing to an array of pixels.
GLboolean	_swrast_stencil_and_ztest_span (GLcontext *ctx, SWspan *span)
	/return GL_TRUE = one or more fragments passed, GL_FALSE = all fragments failed.
void	_swrast_read_stencil_span (GLcontext *ctx, struct gl_renderbuffer *rb, GLint n, GLint x, GLint y, GLstencil stencil[])
	Return a span of stencil values from the stencil buffer.
void	_swrast_write_stencil_span (GLcontext *ctx, GLint n, GLint x, GLint y, const GLstencil stencil[])
	Write a span of stencil values to the stencil buffer.
void	_swrast_clear_stencil_buffer (GLcontext *ctx, struct gl_renderbuffer *rb)
	Clear the stencil buffer.

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Define Documentation

#define STENCIL_ADDRESS	(	X,
		Y		)	(stencilStart + (Y) * stride + (X))

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Function Documentation

void _swrast_clear_stencil_buffer	(	GLcontext *	ctx,
		struct gl_renderbuffer *	rb
	)

Clear the stencil buffer.

void _swrast_read_stencil_span	(	GLcontext *	ctx,
		struct gl_renderbuffer *	rb,
		GLint	n,
		GLint	x,
		GLint	y,
		GLstencil	stencil[]
	)

Return a span of stencil values from the stencil buffer.

Used for glRead/CopyPixels Input: n - how many pixels x,y - location of first pixel Output: stencil - the array of stencil values

GLboolean _swrast_stencil_and_ztest_span	(	GLcontext *	ctx,
		SWspan *	span
	)

/return GL_TRUE = one or more fragments passed, GL_FALSE = all fragments failed.

void _swrast_write_stencil_span	(	GLcontext *	ctx,
		GLint	n,
		GLint	x,
		GLint	y,
		const GLstencil	stencil[]
	)

Write a span of stencil values to the stencil buffer.

This function applies the stencil write mask when needed. Used for glDraw/CopyPixels Input: n - how many pixels x, y - location of first pixel stencil - the array of stencil values

static void apply_stencil_op	(	const GLcontext *	ctx,
		GLenum	oper,
		GLuint	face,
		GLuint	n,
		GLstencil	stencil[],
		const GLubyte	mask[]
	)			[static]

Apply the given stencil operator to the array of stencil values.

Don't touch stencil[i] if mask[i] is zero. Input: n - size of stencil array oper - the stencil buffer operator face - 0 or 1 for front or back face operation stencil - array of stencil values mask - array [n] of flag: 1=apply operator, 0=don't apply operator Output: stencil - modified values

static void apply_stencil_op_to_pixels	(	GLcontext *	ctx,
		GLuint	n,
		const GLint	x[],
		const GLint	y[],
		GLenum	oper,
		GLuint	face,
		const GLubyte	mask[]
	)			[static]

Apply the given stencil operator for each pixel in the array whose mask flag is set.

Note:

This is for software stencil buffers only. Input: n - number of pixels in the span x, y - array of [n] pixels operator - the stencil buffer operator mask - array [n] of flag: 1=apply operator, 0=don't apply operator

static INLINE void compute_pass_fail_masks	(	GLuint	n,
		const GLubyte	origMask[],
		const GLubyte	newMask[],
		GLubyte	passMask[],
		GLubyte	failMask[]
	)			[static]

Compute the zpass/zfail masks by comparing the pre- and post-depth test masks.

static GLboolean do_stencil_test	(	GLcontext *	ctx,
		GLuint	face,
		GLuint	n,
		GLstencil	stencil[],
		GLubyte	mask[]
	)			[static]

Apply stencil test to an array of stencil values (before depth buffering).

Input: face - 0 or 1 for front or back-face polygons n - number of pixels in the array stencil - array of [n] stencil values mask - array [n] of flag: 0=skip the pixel, 1=stencil the pixel Output: mask - pixels which fail the stencil test will have their mask flag set to 0. stencil - updated stencil values (where the test passed) Return: GL_FALSE = all pixels failed, GL_TRUE = zero or more pixels passed.

static GLboolean stencil_and_ztest_pixels	(	GLcontext *	ctx,
		SWspan *	span,
		GLuint	face
	)			[static]

Apply stencil and depth testing to an array of pixels.

This is used both for software and hardware stencil buffers.

The comments in this function are a bit sparse but the code is almost identical to stencil_and_ztest_span(), which is well commented.

Input: n - number of pixels in the array x, y - array of [n] pixel positions z - array [n] of z values mask - array [n] of flags (1=test this pixel, 0=skip the pixel) Output: mask - array [n] of flags (1=stencil and depth test passed) Return: GL_FALSE - all fragments failed the testing GL_TRUE - one or more fragments passed the testing

static GLboolean stencil_and_ztest_span	(	GLcontext *	ctx,
		SWspan *	span,
		GLuint	face
	)			[static]

Apply stencil and depth testing to the span of pixels.

Both software and hardware stencil buffers are acceptable. Input: n - number of pixels in the span x, y - location of leftmost pixel in span z - array [n] of z values mask - array [n] of flags (1=test this pixel, 0=skip the pixel) Output: mask - array [n] of flags (1=stencil and depth test passed) Return: GL_FALSE - all fragments failed the testing GL_TRUE - one or more fragments passed the testing

static GLboolean stencil_test_pixels	(	GLcontext *	ctx,
		GLuint	face,
		GLuint	n,
		const GLint	x[],
		const GLint	y[],
		GLubyte	mask[]
	)			[static]

Apply stencil test to an array of pixels before depth buffering.

Note:

Used for software stencil buffer only. Input: n - number of pixels in the span x, y - array of [n] pixels to stencil mask - array [n] of flag: 0=skip the pixel, 1=stencil the pixel Output: mask - pixels which fail the stencil test will have their mask flag set to 0.

Returns:

GL_FALSE = all pixels failed, GL_TRUE = zero or more pixels passed.

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