Class NVBlendEquationAdvanced
- java.lang.Object
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- org.lwjgl.opengles.NVBlendEquationAdvanced
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public class NVBlendEquationAdvanced extends java.lang.Object
Native bindings to the NV_blend_equation_advanced extension.This extension adds a number of "advanced" blending equations that can be used to perform new color blending operations, many of which are more complex than the standard blend modes provided by unextended OpenGL. This extension provides two different extension string entries:
- NV_blend_equation_advanced: Provides the new blending equations, but guarantees defined results only if each sample is touched no more than once in any single rendering pass. The command BlendBarrierNV() is provided to indicate a boundary between passes.
- NV_blend_equation_advanced_coherent: Provides the new blending equations, and guarantees that blending is done coherently and in API primitive ordering. An enable is provided to allow implementations to opt out of fully coherent blending and instead behave as though only NV_blend_equation_advanced were supported.
Some implementations may support NV_blend_equation_advanced without supporting NV_blend_equation_advanced_coherent.
In unextended OpenGL, the set of blending equations is limited, and can be expressed very simply. The MIN and MAX blend equations simply compute component-wise minimums or maximums of source and destination color components. The FUNC_ADD, FUNC_SUBTRACT, and FUNC_REVERSE_SUBTRACT multiply the source and destination colors by source and destination factors and either add the two products together or subtract one from the other. This limited set of operations supports many common blending operations but precludes the use of more sophisticated transparency and blending operations commonly available in many dedicated imaging APIs.
This extension provides a number of new "advanced" blending equations. Unlike traditional blending operations using the FUNC_ADD equation, these blending equations do not use source and destination factors specified by BlendFunc. Instead, each blend equation specifies a complete equation based on the source and destination colors. These new blend equations are used for both RGB and alpha components; they may not be used to perform separate RGB and alpha blending (via functions like BlendEquationSeparate).
These blending operations are performed using premultiplied colors, where RGB colors stored in the framebuffer are considered to be multiplied by alpha (coverage). The fragment color may be considered premultiplied or non-premultiplied, according the BLEND_PREMULTIPLIED_SRC_NV blending parameter (as specified by the new BlendParameteriNV function). If fragment color is considered non-premultiplied, the (R,G,B) color components are multiplied by the alpha component prior to blending. For non-premultiplied color components in the range [0,1], the corresponding premultiplied color component would have values in the range [0*A,1*A].
Many of these advanced blending equations are formulated where the result of blending source and destination colors with partial coverage have three separate contributions: from the portions covered by both the source and the destination, from the portion covered only by the source, and from the portion covered only by the destination. The blend parameter BLEND_OVERLAP_NV can be used to specify a correlation between source and destination pixel coverage. If set to CONJOINT_NV, the source and destination are considered to have maximal overlap, as would be the case if drawing two objects on top of each other. If set to DISJOINT_NV, the source and destination are considered to have minimal overlap, as would be the case when rendering a complex polygon tessellated into individual non-intersecting triangles. If set to UNCORRELATED_NV (default), the source and destination coverage are assumed to have no spatial correlation within the pixel.
In addition to the coherency issues on implementations not supporting NV_blend_equation_advanced_coherent, this extension has several limitations worth noting. First, the new blend equations are not supported while rendering to more than one color buffer at once; an INVALID_OPERATION will be generated if an application attempts to render any primitives in this unsupported configuration. Additionally, blending precision may be limited to 16-bit floating-point, which could result in a loss of precision and dynamic range for framebuffer formats with 32-bit floating-point components, and in a loss of precision for formats with 12- and 16-bit signed or unsigned normalized integer components.
Requires
GLES 2.0
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Field Summary
Fields Modifier and Type Field Description static int
GL_BLEND_OVERLAP_NV
GL_BLEND_PREMULTIPLIED_SRC_NVThe BLEND_ADVANCED_COHERENT_NV enable is provided if and only if the NV_blend_equation_advanced_coherent extension is supported.static int
GL_BLUE_NV
GL_COLORBURN_NV
GL_COLORDODGE_NVAccepted by themode
parameter of BlendEquation and BlendEquationi.static int
GL_CONJOINT_NV
Accepted by thevalue
parameter of BlendParameteriNV whenpname
is BLEND_OVERLAP_NV.static int
GL_CONTRAST_NV
GL_DARKEN_NV
GL_DIFFERENCE_NVAccepted by themode
parameter of BlendEquation and BlendEquationi.static int
GL_DISJOINT_NV
Accepted by thevalue
parameter of BlendParameteriNV whenpname
is BLEND_OVERLAP_NV.static int
GL_DST_ATOP_NV
GL_DST_IN_NV
GL_DST_NV
GL_DST_OUT_NV
GL_DST_OVER_NV
GL_EXCLUSION_NV
GL_GREEN_NV
GL_HARDLIGHT_NV
GL_HARDMIX_NV
GL_HSL_COLOR_NV
GL_HSL_HUE_NV
GL_HSL_LUMINOSITY_NV
GL_HSL_SATURATION_NV
GL_INVERT_OVG_NV
GL_INVERT_RGB_NV
GL_LIGHTEN_NV
GL_LINEARBURN_NV
GL_LINEARDODGE_NV
GL_LINEARLIGHT_NV
GL_MINUS_CLAMPED_NV
GL_MINUS_NV
GL_MULTIPLY_NV
GL_OVERLAY_NV
GL_PINLIGHT_NV
GL_PLUS_CLAMPED_ALPHA_NV
GL_PLUS_CLAMPED_NV
GL_PLUS_DARKER_NV
GL_PLUS_NV
GL_RED_NV
GL_SCREEN_NV
GL_SOFTLIGHT_NV
GL_SRC_ATOP_NV
GL_SRC_IN_NV
GL_SRC_NV
GL_SRC_OUT_NV
GL_SRC_OVER_NVAccepted by themode
parameter of BlendEquation and BlendEquationi.static int
GL_UNCORRELATED_NV
Accepted by thevalue
parameter of BlendParameteriNV whenpname
is BLEND_OVERLAP_NV.static int
GL_VIVIDLIGHT_NV
GL_XOR_NVAccepted by themode
parameter of BlendEquation and BlendEquationi.
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description static void
glBlendBarrierNV()
static void
glBlendParameteriNV(int pname, int value)
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Field Detail
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GL_BLEND_PREMULTIPLIED_SRC_NV, GL_BLEND_OVERLAP_NV
The BLEND_ADVANCED_COHERENT_NV enable is provided if and only if the NV_blend_equation_advanced_coherent extension is supported. On implementations supporting only NV_blend_equation_advanced, this enable is considered not to exist. Accepted by thepname
parameter of BlendParameteriNV, GetBooleanv, GetIntegerv, GetInteger64v, GetFloatv, and GetDoublev.
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GL_UNCORRELATED_NV, GL_DISJOINT_NV, GL_CONJOINT_NV
Accepted by thevalue
parameter of BlendParameteriNV whenpname
is BLEND_OVERLAP_NV.
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GL_SRC_NV, GL_DST_NV, GL_SRC_OVER_NV, GL_DST_OVER_NV, GL_SRC_IN_NV, GL_DST_IN_NV, GL_SRC_OUT_NV, GL_DST_OUT_NV, GL_SRC_ATOP_NV, GL_DST_ATOP_NV, GL_XOR_NV, GL_MULTIPLY_NV, GL_SCREEN_NV, GL_OVERLAY_NV, GL_DARKEN_NV, GL_LIGHTEN_NV, GL_COLORDODGE_NV, GL_COLORBURN_NV, GL_HARDLIGHT_NV, GL_SOFTLIGHT_NV, GL_DIFFERENCE_NV, GL_EXCLUSION_NV, GL_INVERT_RGB_NV, GL_LINEARDODGE_NV, GL_LINEARBURN_NV, GL_VIVIDLIGHT_NV, GL_LINEARLIGHT_NV, GL_PINLIGHT_NV, GL_HARDMIX_NV, GL_HSL_HUE_NV, GL_HSL_SATURATION_NV, GL_HSL_COLOR_NV, GL_HSL_LUMINOSITY_NV, GL_PLUS_NV, GL_PLUS_CLAMPED_NV, GL_PLUS_CLAMPED_ALPHA_NV, GL_PLUS_DARKER_NV, GL_MINUS_NV, GL_MINUS_CLAMPED_NV, GL_CONTRAST_NV, GL_INVERT_OVG_NV, GL_RED_NV, GL_GREEN_NV, GL_BLUE_NV
Accepted by themode
parameter of BlendEquation and BlendEquationi.
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