Primitive rasterization functions. More...

Collaboration diagram for Rasterization:

Files
file	fragment.c

file	fragment.h

file	line.c

file	line.h

file	point.c

file	point.h

file	triangle.c

file	triangle.h

Classes
struct	SRPLine

struct	SRPPoint

struct	SRPTriangle

typedef struct SRPLine	SRPLine

typedef struct SRPPoint	SRPPoint

typedef struct SRPTriangle	SRPTriangle

static bool	scissorTest (size_t x, size_t y)

static bool	stencilTest (uint8_t stencil, const SRPStencilFaceState s)

static bool	stencilCompare (uint8_t ref, uint8_t stored, uint8_t mask, SRPCompareOp op)

static void	stencilFailOp (uint8_t stencil, const SRPStencilFaceState s)

static void	stencilDepthFailOp (uint8_t stencil, const SRPStencilFaceState s)

static void	stencilPassOp (uint8_t stencil, const SRPStencilFaceState s)

static uint8_t	applyStencilOp (SRPStencilOp op, uint8_t stored, uint8_t ref)

static bool	depthTest (float incoming, float stored)

void	emitFragment (const SRPFramebuffer fb, const SRPShaderProgram sp, int x, int y, SRPFragmentShaderIn *fsIn)

static void	lineInterpolateData (SRPLine line, float t, const SRPShaderProgram restrict sp, SRPInterpolated pInterpolatedBuffer, float depth, float *recIntInvW)

void	rasterizeLine (SRPLine line, const SRPFramebuffer fb, const SRPShaderProgram restrict sp, void interpolatedBuffer)

void	setupLine (SRPLine line, const SRPFramebuffer fb)

static bool	computeMathAndRasterBoundaries (vec3 ss, float pointSize, const SRPFramebuffer fb, vec2 outMinBP, vec2 outMaxBP, int outMinX, int outMaxX, int outMinY, int *outMaxY)

void	rasterizePoint (SRPPoint point, const SRPFramebuffer fb, const SRPShaderProgram *restrict sp)

void	setupPoint (SRPPoint *p)

static float	signedAreaParallelogram (const vec3 restrict a, const vec3 restrict b)

static bool	shouldCullTriangle (const SRPTriangle tri, bool isCCW, bool *isFrontFacing)

static void	triangleChangeWinding (SRPTriangle *tri)

static void	calculateBarycentrics (SRPTriangle *tri, float areaX2, vec2 point)

static bool	isEdgeFlatTopOrLeft (const vec3 *restrict edge)

static void	triangleInterpolateData (SRPTriangle tri, const SRPShaderProgram restrict sp, SRPInterpolated pInterpolatedBuffer, float depth, float *recIntInvW)

void	rasterizeTriangle (SRPTriangle tri, const SRPFramebuffer fb, const SRPShaderProgram restrict sp, void interpolatedBuffer)

bool	setupTriangle (SRPTriangle tri, const SRPFramebuffer fb)

Detailed Description

Primitive rasterization functions.

Typedef Documentation

◆ SRPLine

typedef struct SRPLine SRPLine

Line primitive. Stores data needed for its rasterization

◆ SRPPoint

typedef struct SRPPoint SRPPoint

Point primitive. Stores data needed for its rasterization

◆ SRPTriangle

typedef struct SRPTriangle SRPTriangle

Triangle primitive. Stores data needed for its rasterization

Function Documentation

◆ applyStencilOp()

static uint8_t applyStencilOp	(	SRPStencilOp	op,
		uint8_t	stored,
		uint8_t	ref
	)

inlinestatic

Apply an operation to a stencil value

◆ calculateBarycentrics()

static void calculateBarycentrics	(	SRPTriangle *	tri,
		float	areaX2,
		vec2	point
	)

static

Calculate barycentric coordinates for a point and barycentric coordinates' delta values.

Parameters

[in]	tri	Triangle to calculate barycentric coordinates for. Must have its `ss` and `edge` fields initialized.
[in]	areaX2	The triangle's area multiplied by 2 (to avoid division)
[in]	point	Point to calculate barycentric coordinates for (screen-space)

◆ computeMathAndRasterBoundaries()

static bool computeMathAndRasterBoundaries	(	vec3	ss,
		float	pointSize,
		const SRPFramebuffer *	fb,
		vec2 *	outMinBP,
		vec2 *	outMaxBP,
		int *	outMinX,
		int *	outMaxX,
		int *	outMinY,
		int *	outMaxY
	)

static

Given screen-space point position, compute its math and raster boundaries.

Parameters

[in]	ss	Screen-space point position
[in]	pointSize	Point size, in pixels
[in]	fb	Pointer to the framebuffer, used to clip partially-OOB points
[out]	outMinBP,outMaxBP	Bounding points representing mathematical boundaries
[out]	outMinX,outMaxX,outMinY,outMaxY	Raster boundaries

Returns: true if point is fully OOB, false otherwise

◆ depthTest()

static bool depthTest	(	float	incoming,
		float	stored
	)

inlinestatic

Perform a depth test, respecting the user-set compare operation and whether or not the test is enabled

Parameters

[in]	incoming	The depth value of the currently processed fragment
[in]	stored	The depth value stored in the depth buffer

Returns: true if depth test passes, false otherwise

◆ emitFragment()

void emitFragment	(	const SRPFramebuffer *	fb,
		const SRPShaderProgram *	sp,
		int	x,
		int	y,
		SRPFragmentShaderIn *	fsIn
	)

Perform (early) depth check, run fragment shader, and draw a pixel

Parameters

[in]	fb	The framebuffer to use
[in]	sp	The shader program to use
[in]	x,y	Coordinates of the pixel
[in]	fsIn	Fragment shader input

◆ isEdgeFlatTopOrLeft()

static bool isEdgeFlatTopOrLeft ( const vec3 *restrict edge )

static

Check if a triangle's edge is flat top or left. Assumes counter-clockwise vertex order!

Parameters

[in] edge A pointer to an edge vector (pointing from one vertex to the other)

Returns: Whether or not this edge is flat top or left

◆ lineInterpolateData()

static void lineInterpolateData	(	SRPLine *	line,
		float	t,
		const SRPShaderProgram *restrict	sp,
		SRPInterpolated *	pInterpolatedBuffer,
		float *	depth,
		float *	recIntInvW
	)

static

Interpolate the fragment position and vertex variables inside the line.

Parameters

[in]	line	Line to interpolate data for
[in]	t	Interpolation parameter (0 -> 0th vertex; 1 -> 1st vertex)
[in]	sp	A pointer to shader program to use
[out]	pInterpolatedBuffer	A pointer to the buffer where interpolated variables will appear. Must be big enough to hold all of them
[out]	depth	Fragment depth
[out]	recIntInvW	Reciprocal of interpolated inverse Wclip

◆ rasterizeLine()

void rasterizeLine	(	SRPLine *	line,
		const SRPFramebuffer *	fb,
		const SRPShaderProgram *restrict	sp,
		void *	interpolatedBuffer
	)

Rasterize a point

Parameters

[in]	line	Pointer to the line to draw
[in]	fb	The framebuffer to draw to
[in]	sp	The shader program to use
[in]	interpolatedBuffer	Pointer to a temporary buffer where varyings for each fragment will be stored. Must be big enough to hold all interpolated attributes for ONE vertex.

◆ rasterizePoint()

void rasterizePoint	(	SRPPoint *	point,
		const SRPFramebuffer *	fb,
		const SRPShaderProgram *restrict	sp
	)

Rasterize a point

Parameters

[in]	point	Pointer to the point to draw
[in]	fb	The framebuffer to draw to
[in]	sp	The shader program to use

◆ rasterizeTriangle()

void rasterizeTriangle	(	SRPTriangle *	triangle,
		const SRPFramebuffer *	fb,
		const SRPShaderProgram *restrict	sp,
		void *	interpolatedBuffer
	)

Rasterize a triangle

Parameters

[in]	triangle	Pointer to the triangle to draw
[in]	fb	The framebuffer to draw to
[in]	sp	The shader program to use
[in]	interpolatedBuffer	Pointer to a temporary buffer where varyings for each fragment will be stored. Must be big enough to hold all interpolated attributes for ONE vertex.

◆ scissorTest()

static bool scissorTest	(	size_t	x,
		size_t	y
	)

inlinestatic

Perform a scissor test, respecting the user-set runtime options

Parameters

[in] x,y Window-space position of the currently processed fragment

Returns: true if scissor test passes, false otherwise

◆ setupLine()

void setupLine	(	SRPLine *	line,
		const SRPFramebuffer *	fb
	)

Setup line for rasterization, performing perspective divide and calculating internal variables

Parameters

[in]	line	The line to set up. Its `v` field is required to be filled
[in]	fb	The framebuffer to use for NDC to screen-space conversion

◆ setupPoint()

void setupPoint ( SRPPoint * p )

Perform perspective divide on a point. Created to be structurally similar to setupTriangle(), setupLine()

Parameters

[in] p Point to setup

◆ setupTriangle()

bool setupTriangle	(	SRPTriangle *	tri,
		const SRPFramebuffer *	fb
	)

Setup triangle for rasterization, performing perspective divide and calculating internal variables

Parameters

[in]	tri	The triangle to set up. Its `v` field is required to be filled
[in]	fb	The framebuffer to use for NDC to screen-space conversion

Returns: false if it is culled and should not be rasterized, true otherwise

◆ shouldCullTriangle()

static bool shouldCullTriangle	(	const SRPTriangle *	tri,
		bool *	isCCW,
		bool *	isFrontFacing
	)

static

Determine if a triangle should be culled (back-face culling)

Parameters

[in]	tri	Triangle to check. Must have its `p_ndc` field initialized.
[out]	isCCW	Whether or not the triangle's vertices are in counter-clockwise order
[out]	isFrontFacing	Whether or not the triangle is front facing

Returns: Whether or not the triangle should be culled

◆ signedAreaParallelogram()

static float signedAreaParallelogram	(	const vec3 *restrict	a,
		const vec3 *restrict	b
	)

static

Get a parallelogram's signed area. The two vectors define a parallelogram. Used for barycentric coordinates' initialization in calculateBarycentrics()

◆ stencilCompare()

static bool stencilCompare	(	uint8_t	ref,
		uint8_t	stored,
		uint8_t	mask,
		SRPCompareOp	op
	)

inlinestatic

Compare two masked stencil values with a certain operation

Parameters

[in]	ref	The reference stencil value
[in]	stored	The stored stencil value
[in]	mask	The mask to use with both values
[in]	op	Operation to compare with

◆ stencilDepthFailOp()

static void stencilDepthFailOp	(	uint8_t *	stencil,
		const SRPStencilFaceState *	s
	)

inlinestatic

Apply a "stencil test passed, depth test failed" operation to a stencil value

Parameters

[in]	stencil	Pointer to the current stencil value
[in]	s	Pointer to the stencil state to use

◆ stencilFailOp()

static void stencilFailOp	(	uint8_t *	stencil,
		const SRPStencilFaceState *	s
	)

inlinestatic

Apply a "stencil test failed" operation to a stencil value

Parameters

[in]	stencil	Pointer to the current stencil value
[in]	s	Pointer to the stencil state to use

◆ stencilPassOp()

static void stencilPassOp	(	uint8_t *	stencil,
		const SRPStencilFaceState *	s
	)

inlinestatic

Apply a "stencil and depth tests passed" operation to a stencil value

Parameters

[in]	stencil	Pointer to the current stencil value
[in]	s	Pointer to the stencil state to use

◆ stencilTest()

static bool stencilTest	(	uint8_t *	stencil,
		const SRPStencilFaceState *	s
	)

inlinestatic

Perform an initial stage of the stencil test and potentially apply fail operation to the stencil value. Checks if the stencil test is enabled.

Parameters

[in]	stencil	Pointer to the current stencil value
[in]	s	Pointer to the stencil state to use

◆ triangleChangeWinding()

static void triangleChangeWinding ( SRPTriangle * tri )

static

Change the winding order of a triangle.

Parameters

[in] tri Triangle to change the winding order of. Must have its v, p_ndc and invW fields initialized.

◆ triangleInterpolateData()

static void triangleInterpolateData	(	SRPTriangle *	tri,
		const SRPShaderProgram *restrict	sp,
		SRPInterpolated *	pInterpolatedBuffer,
		float *	depth,
		float *	recIntInvW
	)

static

Interpolate the fragment position and vertex variables inside the triangle.

Parameters

[in]	tri	Triangle to interpolate data for
[in]	sp	A pointer to shader program to use
[out]	pInterpolatedBuffer	A pointer to the buffer where interpolated variables will appear. Must be big enough to hold all of them
[out]	depth	Fragment depth
[out]	recIntInvW	Reciprocal of interpolated inverse Wclip

Files

Classes

Detailed Description

Typedef Documentation

◆ SRPLine

◆ SRPPoint

◆ SRPTriangle

Function Documentation

◆ applyStencilOp()

◆ calculateBarycentrics()

◆ computeMathAndRasterBoundaries()

◆ depthTest()

◆ emitFragment()

◆ isEdgeFlatTopOrLeft()

◆ lineInterpolateData()

◆ rasterizeLine()

◆ rasterizePoint()

◆ rasterizeTriangle()

◆ scissorTest()

◆ setupLine()

◆ setupPoint()

◆ setupTriangle()

◆ shouldCullTriangle()

◆ signedAreaParallelogram()

◆ stencilCompare()

◆ stencilDepthFailOp()

◆ stencilFailOp()

◆ stencilPassOp()

◆ stencilTest()

◆ triangleChangeWinding()

◆ triangleInterpolateData()