Functions related to primitive assembly. More...

Collaboration diagram for Primitive assembly:

Files
file	primitive_assembly.c

file	primitive_assembly.h

file	topology.c

file	topology.h

static void	warnOnExcessVertexCount (const SRPIndexBuffer ib, const SRPVertexBuffer vb, SRPPrimitive prim, size_t startIndex, size_t vertexCount)

static void	resolvePolygonModeOutput (size_t nOutPrimitivesPerClippedTriangle, size_t sizeOutPrimitive)

bool	assembleLines (const SRPIndexBuffer ib, const SRPVertexBuffer vb, const SRPFramebuffer fb, const SRPShaderProgram sp, SRPPrimitive prim, size_t startIndex, size_t vertexCount, size_t outLineCount, SRPLine *outLines)

bool	assemblePoints (const SRPIndexBuffer ib, const SRPVertexBuffer vb, const SRPFramebuffer fb, const SRPShaderProgram sp, size_t startIndex, size_t count, size_t outPointCount, SRPPoint *outPoints)

bool	assembleTrianglesGeneric (const SRPIndexBuffer ib, const SRPVertexBuffer vb, const SRPFramebuffer fb, const SRPShaderProgram sp, SRPPrimitive prim, size_t startIndex, size_t vertexCount, size_t outCount, void *outPrimitives)

size_t	computeTriangleCount (size_t vertexCount, SRPPrimitive prim)

void	resolveTriangleTopology (size_t base, size_t rawTriIdx, SRPPrimitive prim, size_t *out)

size_t	computeLineCount (size_t vertexCount, SRPPrimitive prim)

void	resolveLineTopology (size_t base, size_t rawLineIdx, SRPPrimitive prim, size_t vertexCount, size_t *out)

Detailed Description

Functions related to primitive assembly.

Function Documentation

◆ assembleLines()

bool assembleLines	(	const SRPIndexBuffer *	ib,
		const SRPVertexBuffer *	vb,
		const SRPFramebuffer *	fb,
		const SRPShaderProgram *	sp,
		SRPPrimitive	primitive,
		size_t	startIndex,
		size_t	count,
		size_t *	outLineCount,
		SRPLine **	outLines
	)

Call the vertex shader and assemble lines from vertex or index buffer. If ib == NULL, assembles from vertex buffer, else from index buffer. Uses memory from SRPArena, so the returned points are valid until the next call to arenaReset().

Parameters

[in]	ib	Pointer to index buffer, or `NULL` if assembling from vertex buffer
[in]	vb	Pointer to vertex buffer
[in]	fb	Pointer to the framebuffer to draw to (needed for NDC to screen-space conversion)
[in]	sp	Pointer to the shader program to use
[in]	primitive	Primitive type (one of SRP_PRIM_LINES, SRP_PRIM_LINE_STRIP or SRP_PRIM_LINE_LOOP)
[in]	startIndex	First stream index to assemble
[in]	count	Number of stream indices to assemble
[out]	outLineCount	Amount of assembled lines
[out]	outLines	Pointer to the array of `count` assembled lines

Returns: true if successful, false otherwise. If false if returned, *outLineCount and *outLines are undefined

◆ assemblePoints()

bool assemblePoints	(	const SRPIndexBuffer *	ib,
		const SRPVertexBuffer *	vb,
		const SRPFramebuffer *	fb,
		const SRPShaderProgram *	sp,
		size_t	startIndex,
		size_t	count,
		size_t *	outPointCount,
		SRPPoint **	outPoints
	)

Call the vertex shader and assemble points from vertex or index buffer. If ib == NULL, assembles from vertex buffer, else from index buffer. Uses memory from SRPArena, so the returned points are valid until the next call to arenaReset().

Parameters

[in]	ib	Pointer to index buffer, or `NULL` if assembling from vertex buffer
[in]	vb	Pointer to vertex buffer
[in]	fb	Pointer to the framebuffer to draw to (needed for NDC to screen-space conversion)
[in]	sp	Pointer to the shader program to use
[in]	startIndex	First stream index to assemble
[in]	count	Number of stream indices to assemble
[out]	outPointCount	Amount of assembled points
[out]	outPoints	Pointer to the array of `count` assembled points

Returns: true if successful, false otherwise. If false if returned, *outPointCount and *outPoints are undefined

◆ assembleTrianglesGeneric()

bool assembleTrianglesGeneric	(	const SRPIndexBuffer *	ib,
		const SRPVertexBuffer *	vb,
		const SRPFramebuffer *	fb,
		const SRPShaderProgram *	sp,
		SRPPrimitive	prim,
		size_t	startIndex,
		size_t	vertexCount,
		size_t *	outCount,
		void **	outPrimitives
	)

Call the vertex shader and assemble triangles from vertex or index buffer, possibly converting them to lines or points according to the set polygon mode. If ib == NULL, assembles from vertex buffer, else from index buffer. Uses memory from SRPArena, so the returned triangles are valid until the next call to arenaReset().

Parameters

[in]	ib	Pointer to index buffer, or `NULL` if assembling from vertex buffer
[in]	vb	Pointer to vertex buffer
[in]	fb	Pointer to the framebuffer to draw to (needed for NDC to screen-space conversion)
[in]	sp	Pointer to the shader program to use
[in]	prim	Primitive type (one of SRP_PRIM_TRIANGLES, SRP_PRIM_TRIANGLE_STRIP or SRP_PRIM_TRIANGLE_FAN)
[in]	startIndex	First stream index to assemble
[in]	vertexCount	Number of stream indices to assemble
[out]	outCount	Amount of assembled primitives
[out]	outPrimitives	Pointer to the array of assembled primitives

Returns: true if successful, false otherwise. If false is returned, *outCount and *outPrimitives are 0 and NULL

◆ computeLineCount()

size_t computeLineCount	(	size_t	vertexCount,
		SRPPrimitive	prim
	)

Deduce the number of lines to assemble based on the number of vertices and primitive type

Parameters

[in]	vertexCount	Number of vertices
[in]	prim	Primitive type

Returns: Number of lines that should be assembled

◆ computeTriangleCount()

size_t computeTriangleCount	(	size_t	vertexCount,
		SRPPrimitive	prim
	)

Deduce the number of triangles to assemble based on the number of vertices and primitive type

Parameters

[in]	vertexCount	Number of vertices
[in]	prim	Primitive type

Returns: Number of triangles that should be assembled

◆ resolveLineTopology()

void resolveLineTopology	(	size_t	base,
		size_t	rawLineIdx,
		SRPPrimitive	prim,
		size_t	vertexCount,
		size_t *	out
	)

Determine the stream indices for a line based on its type

Parameters

[in]	base	Base stream index
[in]	rawLineIdx	Index of the primitive to assemble, starting from 0, including culled/skipped lines
[in]	prim	Primitive type
[in]	vertexCount	The total amount of stream vertices for this draw call
[out]	out	Array of size 2 to store the resulting stream indices

◆ resolvePolygonModeOutput()

static void resolvePolygonModeOutput	(	size_t *	nOutPrimitivesPerClippedTriangle,
		size_t *	sizeOutPrimitive
	)

static

Calculate constants for triangle assembly

Parameters

[out]	nOutPrimitivesPerClippedTriangle	How many primitives end up from a clipped triangle
[out]	sizeOutPrimitive	The size of an output primitive (in bytes)

◆ resolveTriangleTopology()

void resolveTriangleTopology	(	size_t	base,
		size_t	rawTriIdx,
		SRPPrimitive	prim,
		size_t *	out
	)

Determine the stream indices for a triangle based on its type

Parameters

[in]	base	Base stream index
[in]	rawTriIdx	Index of the primitive to assemble, starting from 0, including culled triangles
[in]	prim	Primitive type
[out]	out	Array of size 3 to store the resulting stream indices

◆ warnOnExcessVertexCount()

static void warnOnExcessVertexCount	(	const SRPIndexBuffer *	ib,
		const SRPVertexBuffer *	vb,
		SRPPrimitive	prim,
		size_t	startIndex,
		size_t	vertexCount
	)

static

Check if there are excess vertices when drawing some kind of primitive, send a warning if so

See also: assembleTriangles() for parameter documentation

Files

Detailed Description

Function Documentation

◆ assembleLines()

◆ assemblePoints()

◆ assembleTrianglesGeneric()

◆ computeLineCount()

◆ computeTriangleCount()

◆ resolveLineTopology()

◆ resolvePolygonModeOutput()

◆ resolveTriangleTopology()

◆ warnOnExcessVertexCount()