Scarfski/assimp
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

glTF 2.0 Lights import

Browse Source 
Importing of lights according to glTF 2.0 extension KHR_lights_punctual https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_lights_punctual

Since glTF lights are based on PBR they use different attenuation model than conventional lights supported by assimp. It is possible to use attenuation factors in assimp to describe inverse square law fallof. But the light structure does not provide means to save range property. Therefore I resorted to use of metadata. When range parameter is present, I put it into 'PBR_LightRange' metadata of light's node. Please, see comment in glTF2Importer file.
This commit is contained in:
petrmohelnik
2019-08-03 20:51:00 +02:00
parent 1c3e934ae9
commit 9330cca1cd
4 changed files with 159 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

84
code/glTF2/glTF2Importer.cpp
View File

@@ -140,10 +140,10 @@ static aiTextureMapMode ConvertWrappingMode(SamplerWrap gltfWrapMode)
}
}
//static void CopyValue(const glTF2::vec3& v, aiColor3D& out)
//{
// out.r = v[0]; out.g = v[1]; out.b = v[2];
//}
static void CopyValue(const glTF2::vec3& v, aiColor3D& out)
{
out.r = v[0]; out.g = v[1]; out.b = v[2];
}
static void CopyValue(const glTF2::vec4& v, aiColor4D& out)
{
@@ -710,6 +710,69 @@ void glTF2Importer::ImportCameras(glTF2::Asset& r)
}
}
void glTF2Importer::ImportLights(glTF2::Asset& r)
{
if (!r.lights.Size())
return;
mScene->mNumLights = r.lights.Size();
mScene->mLights = new aiLight*[r.lights.Size()];
for (size_t i = 0; i < r.lights.Size(); ++i) {
Light& light = r.lights[i];
aiLight* ail = mScene->mLights[i] = new aiLight();
switch (light.type)
{
case Light::Directional:
ail->mType = aiLightSource_DIRECTIONAL; break;
case Light::Point:
ail->mType = aiLightSource_POINT; break;
case Light::Spot:
ail->mType = aiLightSource_SPOT; break;
}
if (ail->mType != aiLightSource_POINT)
{
ail->mDirection = aiVector3D(0.0f, 0.0f, -1.0f);
ail->mUp = aiVector3D(0.0f, 1.0f, 0.0f);
}
vec3 colorWithIntensity = { light.color[0] * light.intensity, light.color[1] * light.intensity, light.color[2] * light.intensity };
CopyValue(colorWithIntensity, ail->mColorAmbient);
CopyValue(colorWithIntensity, ail->mColorDiffuse);
CopyValue(colorWithIntensity, ail->mColorSpecular);
if (ail->mType == aiLightSource_DIRECTIONAL)
{
ail->mAttenuationConstant = 1.0;
ail->mAttenuationLinear = 0.0;
ail->mAttenuationQuadratic = 0.0;
}
else
{
//in PBR attenuation is calculated using inverse square law which can be expressed
//using assimps equation: 1/(att0 + att1 * d + att2 * d*d) with the following parameters
//this is correct equation for the case when range (see
//https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_lights_punctual)
//is not present. When range is not present it is assumed that it is infinite and so numerator is 1.
//When range is present then numerator might be any value in range [0,1] and then assimps equation
//will not suffice. In this case range is added into metadata in ImportNode function
//and its up to implementation to read it when it wants to
ail->mAttenuationConstant = 0.0;
ail->mAttenuationLinear = 0.0;
ail->mAttenuationQuadratic = 1.0;
}
if (ail->mType == aiLightSource_SPOT)
{
ail->mAngleInnerCone = light.innerConeAngle;
ail->mAngleOuterCone = light.outerConeAngle;
}
}
}
static void GetNodeTransform(aiMatrix4x4& matrix, const glTF2::Node& node) {
if (node.matrix.isPresent) {
CopyValue(node.matrix.value, matrix);
@@ -881,6 +944,18 @@ aiNode* ImportNode(aiScene* pScene, glTF2::Asset& r, std::vector<unsigned int>&
pScene->mCameras[node.camera.GetIndex()]->mName = ainode->mName;
}
if (node.light) {
pScene->mLights[node.light.GetIndex()]->mName = ainode->mName;
//range is optional - see https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_lights_punctual
//it is added to meta data of parent node, because there is no other place to put it
if (node.light->range.isPresent)
{
ainode->mMetaData = aiMetadata::Alloc(1);
ainode->mMetaData->Set(0, "PBR_LightRange", node.light->range.value);
}
}
return ainode;
}
@@ -1150,6 +1225,7 @@ void glTF2Importer::InternReadFile(const std::string& pFile, aiScene* pScene, IO
ImportMeshes(asset);
ImportCameras(asset);
ImportLights(asset);
ImportNodes(asset);