void UPaperSpriteThumbnailRenderer::DrawFrame(class UPaperSprite* Sprite, int32 X, int32 Y, uint32 Width, uint32 Height, FRenderTarget*, FCanvas* Canvas, FBoxSphereBounds* OverrideRenderBounds)
{
const UTexture2D* SourceTexture = nullptr;
if (Sprite != nullptr)
{
SourceTexture = Sprite->GetBakedTexture() ? Sprite->GetBakedTexture() : Sprite->GetSourceTexture();
}
if (SourceTexture != nullptr)
{
const bool bUseTranslucentBlend = SourceTexture->HasAlphaChannel();
// Draw the grid behind the sprite
if (bUseTranslucentBlend)
{
DrawGrid(X, Y, Width, Height, Canvas);
}
// Draw the sprite itself
// Use the baked render data, so we don't have to care about rotations and possibly
// other sprites overlapping in source, UV region, etc.
const TArray<FVector4>& BakedRenderData = Sprite->BakedRenderData;
TArray<FVector2D> CanvasPositions;
TArray<FVector2D> CanvasUVs;
for (int Vertex = 0; Vertex < BakedRenderData.Num(); ++Vertex)
{
new (CanvasPositions) FVector2D(BakedRenderData[Vertex].X, BakedRenderData[Vertex].Y);
new (CanvasUVs) FVector2D(BakedRenderData[Vertex].Z, BakedRenderData[Vertex].W);
}
// Determine the bounds to use
FBoxSphereBounds* RenderBounds = OverrideRenderBounds;
FBoxSphereBounds FrameBounds;
if (RenderBounds == nullptr)
{
FrameBounds = Sprite->GetRenderBounds();
RenderBounds = &FrameBounds;
}
const FVector MinPoint3D = RenderBounds->GetBoxExtrema(0);
const FVector MaxPoint3D = RenderBounds->GetBoxExtrema(1);
const FVector2D MinPoint(FVector::DotProduct(MinPoint3D, PaperAxisX), FVector::DotProduct(MinPoint3D, PaperAxisY));
const FVector2D MaxPoint(FVector::DotProduct(MaxPoint3D, PaperAxisX), FVector::DotProduct(MaxPoint3D, PaperAxisY));
const float UnscaledWidth = MaxPoint.X - MinPoint.X;
const float UnscaledHeight = MaxPoint.Y - MinPoint.Y;
const FVector2D Origin(X + Width * 0.5f, Y + Height * 0.5f);
const bool bIsWider = (UnscaledWidth > 0.0f) && (UnscaledHeight > 0.0f) && (UnscaledWidth > UnscaledHeight);
const float ScaleFactor = bIsWider ? (Width / UnscaledWidth) : (Height / UnscaledHeight);
// Scale and recenter
const FVector2D CanvasPositionCenter = (MaxPoint + MinPoint) * 0.5f;
for (int Vertex = 0; Vertex < CanvasPositions.Num(); ++Vertex)
{
CanvasPositions[Vertex] = (CanvasPositions[Vertex] - CanvasPositionCenter) * ScaleFactor + Origin;
CanvasPositions[Vertex].Y = Height - CanvasPositions[Vertex].Y;
}
// Draw triangles
if ((CanvasPositions.Num() > 0) && (SourceTexture->Resource != nullptr))
{
TArray<FCanvasUVTri> Triangles;
const FLinearColor SpriteColor(FLinearColor::White);
for (int Vertex = 0; Vertex < CanvasPositions.Num(); Vertex += 3)
{
FCanvasUVTri* Triangle = new (Triangles) FCanvasUVTri();
Triangle->V0_Pos = CanvasPositions[Vertex + 0]; Triangle->V0_UV = CanvasUVs[Vertex + 0]; Triangle->V0_Color = SpriteColor;
Triangle->V1_Pos = CanvasPositions[Vertex + 1]; Triangle->V1_UV = CanvasUVs[Vertex + 1]; Triangle->V1_Color = SpriteColor;
Triangle->V2_Pos = CanvasPositions[Vertex + 2]; Triangle->V2_UV = CanvasUVs[Vertex + 2]; Triangle->V2_Color = SpriteColor;
}
FCanvasTriangleItem CanvasTriangle(Triangles, SourceTexture->Resource);
CanvasTriangle.BlendMode = bUseTranslucentBlend ? ESimpleElementBlendMode::SE_BLEND_Translucent : ESimpleElementBlendMode::SE_BLEND_Opaque;
Canvas->DrawItem(CanvasTriangle);
}
}
else
{
// Fallback for a bogus sprite
DrawGrid(X, Y, Width, Height, Canvas);
}
}
