GlfSimpleLight
HdStLight::_ApproximateAreaLight(SdfPath const &id,
HdSceneDelegate *sceneDelegate)
{
// Get the color of the light
GfVec3f hdc = sceneDelegate->GetLightParamValue(id, HdStLightTokens->color)
.Get<GfVec3f>();
// Extract intensity
float intensity =
sceneDelegate->GetLightParamValue(id, HdLightTokens->intensity)
.Get<float>();
// Extract the exposure of the light
float exposure =
sceneDelegate->GetLightParamValue(id, HdLightTokens->exposure)
.Get<float>();
intensity *= powf(2.0f, GfClamp(exposure, -50.0f, 50.0f));
// Calculate the final color of the light
GfVec4f c(hdc[0]*intensity, hdc[1]*intensity, hdc[2]*intensity, 1.0f);
// Get the transform of the light
GfMatrix4d transform = _params[HdTokens->transform].Get<GfMatrix4d>();
GfVec3d hdp = transform.ExtractTranslation();
GfVec4f p = GfVec4f(hdp[0], hdp[1], hdp[2], 1.0f);
// Create the Glf Simple Light object that will be used by the rest
// of the pipeline. No support for shadows for this translated light.
GlfSimpleLight l;
l.SetPosition(p);
l.SetDiffuse(c);
l.SetHasShadow(false);
return l;
}
/* static */
GlfSimpleLightingContextRefPtr
px_vp20Utils::GetLightingContextFromDrawContext(
const MHWRender::MDrawContext& context)
{
const GfVec4f blackColor(0.0f, 0.0f, 0.0f, 1.0f);
const GfVec4f whiteColor(1.0f, 1.0f, 1.0f, 1.0f);
GlfSimpleLightingContextRefPtr lightingContext =
GlfSimpleLightingContext::New();
MStatus status;
unsigned int numMayaLights =
context.numberOfActiveLights(MHWRender::MDrawContext::kFilteredToLightLimit,
&status);
if (status != MS::kSuccess || numMayaLights < 1) {
return lightingContext;
}
bool viewDirectionAlongNegZ = context.viewDirectionAlongNegZ(&status);
if (status != MS::kSuccess) {
// If we fail to find out the view direction for some reason, assume
// that it's along the negative Z axis (OpenGL).
viewDirectionAlongNegZ = true;
}
GlfSimpleLightVector lights;
for (unsigned int i = 0; i < numMayaLights; ++i) {
MHWRender::MLightParameterInformation* mayaLightParamInfo =
context.getLightParameterInformation(i);
if (!mayaLightParamInfo) {
continue;
}
// Setup some default values before we read the light parameters.
bool lightEnabled = true;
bool lightHasPosition = false;
GfVec4f lightPosition(0.0f, 0.0f, 0.0f, 1.0f);
bool lightHasDirection = false;
GfVec3f lightDirection(0.0f, 0.0f, -1.0f);
if (!viewDirectionAlongNegZ) {
// The convention for DirectX is positive Z.
lightDirection[2] = 1.0f;
}
float lightIntensity = 1.0f;
GfVec4f lightColor = blackColor;
bool lightEmitsDiffuse = true;
bool lightEmitsSpecular = false;
float lightDecayRate = 0.0f;
float lightDropoff = 0.0f;
// The cone angle is 180 degrees by default.
GfVec2f lightCosineConeAngle(-1.0f);
float lightShadowBias = 0.0f;
bool lightShadowOn = false;
bool globalShadowOn = false;
MStringArray paramNames;
mayaLightParamInfo->parameterList(paramNames);
for (unsigned int paramIndex = 0; paramIndex < paramNames.length(); ++paramIndex) {
const MString paramName = paramNames[paramIndex];
const MHWRender::MLightParameterInformation::ParameterType paramType =
mayaLightParamInfo->parameterType(paramName);
const MHWRender::MLightParameterInformation::StockParameterSemantic paramSemantic =
mayaLightParamInfo->parameterSemantic(paramName);
MIntArray intValues;
MFloatArray floatValues;
switch (paramType) {
case MHWRender::MLightParameterInformation::kBoolean:
case MHWRender::MLightParameterInformation::kInteger:
mayaLightParamInfo->getParameter(paramName, intValues);
break;
case MHWRender::MLightParameterInformation::kFloat:
case MHWRender::MLightParameterInformation::kFloat2:
case MHWRender::MLightParameterInformation::kFloat3:
case MHWRender::MLightParameterInformation::kFloat4:
mayaLightParamInfo->getParameter(paramName, floatValues);
break;
default:
// Unsupported paramType.
continue;
break;
}
switch (paramSemantic) {
case MHWRender::MLightParameterInformation::kLightEnabled:
_GetLightingParam(intValues, floatValues, lightEnabled);
break;
case MHWRender::MLightParameterInformation::kWorldPosition:
if (_GetLightingParam(intValues, floatValues, lightPosition)) {
lightHasPosition = true;
}
break;
case MHWRender::MLightParameterInformation::kWorldDirection:
if (_GetLightingParam(intValues, floatValues, lightDirection)) {
lightHasDirection = true;
}
break;
case MHWRender::MLightParameterInformation::kIntensity:
_GetLightingParam(intValues, floatValues, lightIntensity);
break;
case MHWRender::MLightParameterInformation::kColor:
_GetLightingParam(intValues, floatValues, lightColor);
break;
case MHWRender::MLightParameterInformation::kEmitsDiffuse:
_GetLightingParam(intValues, floatValues, lightEmitsDiffuse);
break;
case MHWRender::MLightParameterInformation::kEmitsSpecular:
_GetLightingParam(intValues, floatValues, lightEmitsSpecular);
break;
case MHWRender::MLightParameterInformation::kDecayRate:
_GetLightingParam(intValues, floatValues, lightDecayRate);
break;
case MHWRender::MLightParameterInformation::kDropoff:
_GetLightingParam(intValues, floatValues, lightDropoff);
break;
case MHWRender::MLightParameterInformation::kCosConeAngle:
_GetLightingParam(intValues, floatValues, lightCosineConeAngle);
break;
case MHWRender::MLightParameterInformation::kShadowBias:
_GetLightingParam(intValues, floatValues, lightShadowBias);
break;
case MHWRender::MLightParameterInformation::kShadowOn:
_GetLightingParam(intValues, floatValues, lightShadowOn);
break;
case MHWRender::MLightParameterInformation::kGlobalShadowOn:
_GetLightingParam(intValues, floatValues, globalShadowOn);
break;
default:
// Unsupported paramSemantic.
continue;
break;
}
if (!lightEnabled) {
// Stop reading light parameters if the light is disabled.
break;
}
}
if (!lightEnabled) {
// Skip to the next light if this light is disabled.
continue;
}
lightColor[0] *= lightIntensity;
lightColor[1] *= lightIntensity;
lightColor[2] *= lightIntensity;
// Populate a GlfSimpleLight from the light information from Maya.
GlfSimpleLight light;
GfVec4f lightAmbient = blackColor;
GfVec4f lightDiffuse = blackColor;
GfVec4f lightSpecular = blackColor;
// We receive the cone angle from Maya as a pair of floats which
// includes the penumbra, but GlfSimpleLights don't currently support
// that, so we only use the primary cone angle value.
float lightCutoff = GfRadiansToDegrees(std::acos(lightCosineConeAngle[0]));
float lightFalloff = lightDropoff;
// decayRate is actually an enum in Maya that we receive as a float:
// - 0.0 = no attenuation
// - 1.0 = linear attenuation
// - 2.0 = quadratic attenuation
// - 3.0 = cubic attenuation (not supported by GlfSimpleLight)
GfVec3f lightAttenuation(0.0f);
if (lightDecayRate > 1.5) {
// Quadratic attenuation.
lightAttenuation[2] = 1.0f;
} else if (lightDecayRate > 0.5f) {
// Linear attenuation.
lightAttenuation[1] = 1.0f;
} else {
// No/constant attenuation.
lightAttenuation[0] = 1.0f;
}
if (lightHasDirection && !lightHasPosition) {
// This is a directional light. Set the direction as its position.
lightPosition[0] = -lightDirection[0];
lightPosition[1] = -lightDirection[1];
lightPosition[2] = -lightDirection[2];
lightPosition[3] = 0.0f;
// Revert direction to the default value.
lightDirection = GfVec3f(0.0f, 0.0f, -1.0f);
if (!viewDirectionAlongNegZ) {
lightDirection[2] = 1.0f;
}
}
if (!lightHasPosition && !lightHasDirection) {
// This is an ambient light.
lightAmbient = lightColor;
} else {
if (lightEmitsDiffuse) {
lightDiffuse = lightColor;
}
if (lightEmitsSpecular) {
// XXX: It seems that the specular color cannot be specified
// separately from the diffuse color on Maya lights.
lightSpecular = lightColor;
}
}
light.SetAmbient(lightAmbient);
light.SetDiffuse(lightDiffuse);
light.SetSpecular(lightSpecular);
light.SetPosition(lightPosition);
light.SetSpotDirection(lightDirection);
light.SetSpotCutoff(lightCutoff);
light.SetSpotFalloff(lightFalloff);
light.SetAttenuation(lightAttenuation);
light.SetShadowBias(lightShadowBias);
light.SetHasShadow(lightShadowOn && globalShadowOn);
lights.push_back(light);
}
lightingContext->SetLights(lights);
// XXX: These material settings match what we used to get when we read the
// material from OpenGL. This should probably eventually be something more
// sophisticated.
GlfSimpleMaterial material;
material.SetAmbient(whiteColor);
material.SetDiffuse(whiteColor);
material.SetSpecular(blackColor);
material.SetEmission(blackColor);
material.SetShininess(0.0001f);
lightingContext->SetMaterial(material);
lightingContext->SetSceneAmbient(blackColor);
return lightingContext;
}