/// <summary>
/// Generates the shadow map to be used when rendering this light.
/// </summary>
/// <remarks>If this instance is not to cast shadows the shadow map is cleared.</remarks>
/// <param name="renderSystem">The render system to render with.</param>
/// <param name="shadowMap">The shadow map to render on</param>
protected virtual void GenerateShadowMap(DeferredRenderSystem renderSystem, RenderTarget2D shadowMap)
{
RenderTarget2D intermediateShadowMap = renderSystem.RenderTargets.GetTemporaryRenderTarget(SurfaceFormat.Color); // Intermediate map used for selective sampling
RectangleF lightDrawBounds = this.GetWorldDrawBounds();
renderSystem.GraphicsDevice.SetRenderTarget(shadowMap);
renderSystem.ClearCurrentRenderTarget(Color.White); // Clear the core shadow map
// Only render the shadows if we are to cast them
if (this.CastsShadows)
{
// Render the shadow caused by each object within the lights range
List <SpriteBase> objectList = this.World.GetSpriteObjectsInArea(lightDrawBounds).Where(currObj => (currObj.RenderOptions & SpriteRenderOptions.CastsShadows) != 0).OrderBy(s => s.LayerDepth).ToList();
if (objectList.Count > 0)
{
int lastLayerDepth = 0;
int lastLayerDepthIndex = 0;
bool renderedShadow = false; // This is used so that we don't bother occluding objects if we didn't even render anything
lastLayerDepth = (int)objectList[0].LayerDepth;
for (int objectIndex = 0; objectIndex < objectList.Count; objectIndex++)
{
SpriteBase currObj = objectList[objectIndex];
RectangleF spriteWorldBounds = currObj.SpriteWorldBounds;
// If the object we found doesn't cast shadows (or we're inside it), skip it
if (spriteWorldBounds.Contains(base.Position))
{
continue;
}
this.shadowMapShader.ConfigureShader(renderSystem); // Configure the shader
this.shadowMapShader.GetParameter("viewProjection").SetValue(renderSystem.GameCamera.GetViewProjectionMatrix(renderSystem));
this.shadowMapShader.GetParameter("cameraPosition").SetValue(renderSystem.GameCamera.PixelPosition);
// If we switched light planes remove occlusion from all previous objects
if (lastLayerDepth != (int)currObj.LayerDepth)
{
// Only occlude if we actually rendered something
if (renderedShadow)
{
// Loop through all the objects between the last layer index and the current index
for (int clearObjIndex = lastLayerDepthIndex; clearObjIndex < objectIndex; clearObjIndex++)
{
this.ProcessSpriteDepthTransition(renderSystem, objectList[clearObjIndex]);
}
}
// Save the last values
lastLayerDepth = (int)currObj.LayerDepth;
lastLayerDepthIndex = objectIndex;
renderedShadow = false; // Reset this
}
// Create the shadow map caused by the current sprite
this.shadowMapShader.ApplyPass(0);
// Construct the vertex primitive to mask with
Vector2[] extrema;
if (currObj.SpriteWorldShape != null)
{
extrema = currObj.SpriteWorldShape.GetRelativeExtrema(base.Position); // Get the extrema that cause the shadow
}
else
{
extrema = spriteWorldBounds.GetRelativeExtrema(base.Position); // Get the extrema that cause the shadow
}
Vector2 widthVector = Vector2.Normalize(extrema[0] - base.Position); // Get the vector to the first extrema
Vector2 heightVector = Vector2.Normalize(extrema[1] - base.Position); // Get the vector to the second extrema
VertexPrimitive shadowArea = new VertexPrimitive(PrimitiveType.TriangleStrip, 4);
shadowArea.Add(extrema[0]);
shadowArea.Add(extrema[1]);
// Let's extend the shadow vector until it hits the edge of the draw bounds
shadowArea.Add(lightDrawBounds.CastInternalRay(extrema[0], widthVector));
shadowArea.Add(lightDrawBounds.CastInternalRay(extrema[1], heightVector));
// Let's get the remaining verts that might exist to finish up the rect
List <Vector2> interiorVerts = lightDrawBounds.GetInteriorVertices(base.Position, widthVector, heightVector);
shadowArea.Add(interiorVerts); // Add the interior verts (if any exist)
renderSystem.DirectScreenPaint(shadowArea); // Render the shadow
renderedShadow = true; // We just rendered a shadow; keep track of that
}
// Loop through all the objects between the last layer index and the current index
if (renderedShadow)
{
// Remove the shadows over the LAST shadow plane
for (int clearObjIndex = lastLayerDepthIndex; clearObjIndex < objectList.Count; clearObjIndex++)
{
this.ProcessSpriteDepthTransition(renderSystem, objectList[clearObjIndex]);
}
// Blur the shadow map if enabled
if (!float.IsPositiveInfinity(this.minShadowBlurDistance))
{
renderSystem.GraphicsDevice.SetRenderTarget(intermediateShadowMap); // We need to render to a temp target
// Configure the shader
this.shadowMapShader.ConfigureShader(renderSystem, 1);
// Set parameters
this.shadowMapShader.GetParameter("viewProjection").SetValue(renderSystem.GameCamera.GetViewProjectionMatrix(renderSystem));
this.shadowMapShader.GetParameter("cameraPosition").SetValue(renderSystem.GameCamera.PixelPosition);
this.shadowMapShader.GetParameter("lightPosition").SetValue(base.PixelPosition);
this.shadowMapShader.GetParameter("maxBlurDistance").SetValue(this.World.GetPixelFromWorld(this.maxShadowBlurDistance));
this.shadowMapShader.GetParameter("minBlurDistance").SetValue(this.World.GetPixelFromWorld(this.maxShadowBlurDistance));
this.shadowMapShader.GetParameter("shadowMap").SetValue(shadowMap);
this.shadowMapShader.ApplyPass(0);
renderSystem.DirectScreenPaint(lightDrawBounds); // Render the shadow
renderSystem.GraphicsDevice.SetRenderTarget(shadowMap); // Set the shadow map for final render
// Update shadow map
this.shadowMapShader.GetParameter("shadowMap").SetValue(intermediateShadowMap);
this.shadowMapShader.ApplyPass(0);
renderSystem.DirectScreenPaint(lightDrawBounds); // Render
}
}
}
}
renderSystem.SetRenderTargets(RenderTargetTypes.None, 0); // Resolve the render target
renderSystem.RenderTargets.ReleaseTemporaryRenderTarget(intermediateShadowMap);
}