Multi-layer rendering support

src/main/kotlin/mods/betterfoliage/render/block/vanilla/Grass.kt

@@ -2,6 +2,7 @@ package mods.betterfoliage.render.block.vanilla
 
 import mods.betterfoliage.BetterFoliage
 import mods.betterfoliage.BetterFoliageMod
+import mods.betterfoliage.chunk.BlockCtx
 import mods.betterfoliage.config.BlockConfig
 import mods.betterfoliage.config.Config
 import mods.betterfoliage.config.isSnow
@@ -9,6 +10,7 @@ import mods.betterfoliage.integration.ShadersModIntegration
 import mods.betterfoliage.model.Color
 import mods.betterfoliage.model.HalfBakedSpecialWrapper
 import mods.betterfoliage.model.HalfBakedWrapperKey
+import mods.betterfoliage.model.SpecialRenderData
 import mods.betterfoliage.model.SpecialRenderModel
 import mods.betterfoliage.model.SpriteSetDelegate
 import mods.betterfoliage.model.buildTufts
@@ -16,7 +18,9 @@ import mods.betterfoliage.model.fullCubeTextured
 import mods.betterfoliage.model.tuftModelSet
 import mods.betterfoliage.model.tuftShapeSet
 import mods.betterfoliage.render.lighting.LightingPreferredFace
+import mods.betterfoliage.render.pipeline.Layers
 import mods.betterfoliage.render.pipeline.RenderCtxBase
+import mods.betterfoliage.render.pipeline.extendLayers
 import mods.betterfoliage.resource.discovery.BakeWrapperManager
 import mods.betterfoliage.resource.discovery.ConfigurableBlockMatcher
 import mods.betterfoliage.resource.discovery.ConfigurableModelDiscovery
@@ -28,12 +32,14 @@ import mods.betterfoliage.util.LazyInvalidatable
 import mods.betterfoliage.util.LazyMapInvalidatable
 import mods.betterfoliage.util.averageColor
 import mods.betterfoliage.util.colorOverride
-import mods.betterfoliage.util.get
+import mods.betterfoliage.util.idxOrNull
 import mods.betterfoliage.util.logColorOverride
 import mods.betterfoliage.util.randomI
+import net.minecraft.client.renderer.RenderType
 import net.minecraft.util.Direction.DOWN
 import net.minecraft.util.Direction.UP
 import net.minecraft.util.ResourceLocation
+import java.util.Random
 
 object StandardGrassDiscovery : ConfigurableModelDiscovery() {
     override val matchClasses: ConfigurableBlockMatcher get() = BlockConfig.grassBlocks
@@ -42,6 +48,7 @@ object StandardGrassDiscovery : ConfigurableModelDiscovery() {
     override fun processModel(ctx: ModelDiscoveryContext, textureMatch: List<ResourceLocation>) {
         ctx.addReplacement(StandardGrassKey(textureMatch[0], null))
         BetterFoliage.blockTypes.grass.add(ctx.blockState)
+        ctx.blockState.block.extendLayers()
     }
 }
 
@@ -60,6 +67,18 @@ data class StandardGrassKey(
     }
 }
 
+class GrassRenderData(
+    val isSnowed: Boolean,
+    val connectedGrassIdx: Int?,
+    val tuftIdx: Int?
+): SpecialRenderData {
+    override fun canRenderInLayer(layer: RenderType) = when {
+        connectedGrassIdx != null && layer == Layers.connectedGrass -> true
+        tuftIdx != null && layer == Layers.tufts -> true
+        else -> false
+    }
+}
+
 class StandardGrassModel(
     wrapped: SpecialRenderModel,
     key: StandardGrassKey
@@ -70,8 +89,8 @@ class StandardGrassModel(
     val fullBlock by grassFullBlockMeshes.delegate(key)
     val tuftLighting = LightingPreferredFace(UP)
 
-    override fun render(ctx: RenderCtxBase, noDecorations: Boolean) {
-        if (!Config.enabled || noDecorations) return super.render(ctx, noDecorations)
+    override fun prepare(ctx: BlockCtx, random: Random): Any {
+        if (!Config.enabled) return Unit
 
         val stateBelow = ctx.state(DOWN)
         val stateAbove = ctx.state(UP)
@@ -81,18 +100,32 @@ class StandardGrassModel(
                 (!isSnowed || Config.connectedGrass.snowEnabled) &&
                 BetterFoliage.blockTypes.run { stateBelow in grass || stateBelow in dirt }
 
-        if (connected) {
-            ctx.renderQuads(if (isSnowed) snowFullBlockMeshes[ctx.random] else fullBlock[ctx.random])
-        } else {
-            super.render(ctx, noDecorations)
-        }
-
-        if (Config.shortGrass.enabled(ctx.random) && Config.shortGrass.grassEnabled && (isAir || isSnowed)) {
-            ctx.vertexLighter = tuftLighting
-            ShadersModIntegration.grass(ctx, Config.shortGrass.shaderWind) {
-                ctx.renderQuads(if (isSnowed) tuftSnowed[ctx.random] else tuftNormal[ctx.random])
+        return GrassRenderData(
+            isSnowed = isSnowed,
+            connectedGrassIdx = random.idxOrNull(if (isSnowed) snowFullBlockMeshes else fullBlock) { connected },
+            tuftIdx = random.idxOrNull(if (isSnowed) tuftSnowed else tuftNormal) {
+                Config.shortGrass.enabled(random) &&
+                        Config.shortGrass.grassEnabled &&
+                        (isAir || isSnowed)
             }
-        }
+        )
+    }
+
+    override fun renderLayer(ctx: RenderCtxBase, data: Any, layer: RenderType) {
+        if (data is GrassRenderData) {
+            if (data.connectedGrassIdx != null) {
+                if (layer == Layers.connectedGrass)
+                    ctx.renderQuads((if (data.isSnowed) snowFullBlockMeshes else fullBlock)[data.connectedGrassIdx])
+            } else {
+                super.renderLayer(ctx, data, layer)
+            }
+            if (data.tuftIdx != null && layer == Layers.tufts) {
+                ctx.vertexLighter = tuftLighting
+                ShadersModIntegration.grass(ctx, Config.shortGrass.shaderWind) {
+                    ctx.renderQuads((if (data.isSnowed) tuftSnowed else tuftNormal)[data.tuftIdx])
+                }
+            }
+        } else super.renderLayer(ctx, data, layer)
     }
 
     companion object {