org.lwjgl.opengl

Class NVConservativeRasterPreSnapTriangles

java.lang.Object

org.lwjgl.opengl.NVConservativeRasterPreSnapTriangles

public class NVConservativeRasterPreSnapTriangles
extends java.lang.Object

When CONSERVATIVE_RASTERIZATION_NV is enabled, the fragments generated for a primitive are conservative with respect to the primitive after snapping to sub-pixel grid. This extension provides a new mode of rasterization for triangles where the fragments generated are conservative with respect to the primitive at infinite precision before vertex snapping.

When the conservative raster mode is set to CONSERVATIVE_RASTER_MODE_PRE_SNAP_TRIANGLES_NV, triangles are rasterized more conservatively, and may generate fragments not generated when the mode is CONSERVATIVE_RASTER_MODE_POST_SNAP_NV (default). In particular it may generate fragments for pixels covered by triangles with zero area, or for pixels that are adjacent to but not covered by any triangle. This modified behavior may be useful in compensating for rounding errors caused by snapping vertex positions to a sub-pixel grid during rasterization. It's possible that a non-degenerate triangle becomes degenerate due to snapping. It's additionally possible that rounding errors in computing the position of a vertex or from snapping may cause a primitive that would cover a pixel at infinite precision to fail to cover the pixel post-snap. Rasterizing such primitives more conservatively may be useful for "binning" algorithms described in NV_conservative_raster.

Requires NV_conservative_raster.

Field Summary

Fields

Modifier and Type	Field and Description
static int	GL_CONSERVATIVE_RASTER_MODE_NV Accepted by the pname parameter of ConservativeRasterParameteriNV.
static int	GL_CONSERVATIVE_RASTER_MODE_POST_SNAP_NV Accepted by the param parameter of ConservativeRasterParameteriNV.
static int	GL_CONSERVATIVE_RASTER_MODE_PRE_SNAP_TRIANGLES_NV Accepted by the param parameter of ConservativeRasterParameteriNV.

Method Summary

Modifier and Type	Method and Description
static void	glConservativeRasterParameteriNV(int pname, int param) When CONSERVATIVE_RASTERIZATION_NV is enabled, the rasterization behavior may be controlled by calling the this command.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

GL_CONSERVATIVE_RASTER_MODE_NV

public static final int GL_CONSERVATIVE_RASTER_MODE_NV

Accepted by the pname parameter of ConservativeRasterParameteriNV.

See Also:

Constant Field Values

GL_CONSERVATIVE_RASTER_MODE_POST_SNAP_NV

public static final int GL_CONSERVATIVE_RASTER_MODE_POST_SNAP_NV

Accepted by the param parameter of ConservativeRasterParameteriNV.

See Also:

Constant Field Values

GL_CONSERVATIVE_RASTER_MODE_PRE_SNAP_TRIANGLES_NV

public static final int GL_CONSERVATIVE_RASTER_MODE_PRE_SNAP_TRIANGLES_NV

Accepted by the param parameter of ConservativeRasterParameteriNV.

See Also:

Constant Field Values

Method Detail

glConservativeRasterParameteriNV

public static void glConservativeRasterParameteriNV(int pname,
                                                    int param)

When CONSERVATIVE_RASTERIZATION_NV is enabled, the rasterization behavior may be controlled by calling the this command.

If the mode is set to CONSERVATIVE_RASTER_MODE_POST_SNAP_NV, the generated fragments are conservative w.r.t the primitive after it is snapped to sub-pixel grid. If the mode is set to CONSERVATIVE_RASTER_MODE_PRE_SNAP_TRIANGLES_NV the fragments generated for triangles will be conservative w.r.t the triangle at infinite precision. Since non-degenerate triangles may become degenerate due to vertex snapping, this mode will generate fragments for zero area triangles that are otherwise culled when the mode is CONSERVATIVE_RASTER_MODE_POST_SNAP_NV. This mode may also generate fragments for pixels that are within half a sub-pixel distance away from a triangle's infinite precision boundary. The default mode is set to CONSERVATIVE_RASTER_MODE_POST_SNAP_NV.

Parameters:

pname - the parameter to set. Must be:

CONSERVATIVE_RASTER_MODE_NV

param - specifies the conservative raster mode to be used. One of:

CONSERVATIVE_RASTER_MODE_POST_SNAP_NV

CONSERVATIVE_RASTER_MODE_PRE_SNAP_TRIANGLES_NV