Damage Shaders (NvBlastExtShaders)

Blast Extensions provide basic implementations of programs generating fracture commands, the first step in breaking a Blast™ Actor, see Damage and Fracturing. These programs come as two shader functions (callbacks) for Actors with a support graph and Actors with just one chunk respectively. The NvBlastDamageProgram containing both shaders can be used for low-level directly (NvBlastActorGenerateFracture) or for TkActor's damage and fracture functions.

    NvBlastDamageProgram damageProgram = { NvBlastExtShearGraphShader, NvBlastExtShearSubgraphShader };
+

+The appropriate shader will be called for an Actor being processed, along with the necessary Actor's geometry and program parameters. The parameters (NvBlastProgramParams) are set to contain

+1. Material, something that describes an Actor properties (e.g. mass, stiffness, fragility) which are not expected to be changed often.

+2. Damage description, something that describes a particular damage event (e.g. position, radius and force of explosion).

    NvBlastExtMaterial material = { singleChunkThreshold, graphChunkThreshold, bondTangentialThreshold, bondNormalThreshold, damageAttenuation };
+    NvBlastExtRadialDamageDesc damageDesc = { compressive, posX, posY, posZ, minR, maxR };
+

+When used with TkActor::damage() functions, TkActor will cache the necessary data for deferred processing through TkGroup. This includes accumulating damage requests for the same material and program parameter combination. A default material can be set for a TkFamily that all its Actors uses.

    tkGroup->addActor(*tkActor);
+    tkActor->damage(damageProgram, damageDesc0, sizeof(NvBlastExtRadialDamageDesc), &material);
+    tkActor->damage(damageProgram, damageDesc1, sizeof(NvBlastExtRadialDamageDesc), &material);
+    tkGroup->process();
+    tkGroup->sync();
+

+In contrast, the user is responsible for providing all the damage descriptions persisting through the low-level NvBlastActorGenerateFracture call when not using the Tk layer.

    NvBlastProgramParams programParams = { damageDescs, 2, &material };
+    NvBlastActorGenerateFracture(commandBuffers, actor, damageProgram, &programParams, nullptr, nullptr);
+