[WIP] start 1.15 port

reorganize packages to match Fabric version
use util classes from Fabric version

src/main/kotlin/mods/betterfoliage/integration/ShadersModIntegration.kt

@@ -0,0 +1,66 @@
+package mods.betterfoliage.integration
+
+import mods.betterfoliage.BetterFoliage
+import mods.betterfoliage.config.BlockConfig
+import mods.betterfoliage.texture.LeafRegistry
+import mods.octarinecore.*
+import mods.betterfoliage.render.old.CombinedContext
+import mods.betterfoliage.util.allAvailable
+import mods.betterfoliage.util.get
+import net.minecraft.block.BlockRenderType
+import net.minecraft.block.BlockRenderType.MODEL
+import net.minecraft.block.BlockState
+import net.minecraft.block.Blocks
+import net.minecraft.util.math.BlockPos
+import net.minecraft.world.ILightReader
+import org.apache.logging.log4j.Level.INFO
+
+/**
+ * Integration for ShadersMod.
+ */
+object ShadersModIntegration {
+
+    @JvmStatic val isAvailable = allAvailable(SVertexBuilder, SVertexBuilder.pushState, SVertexBuilder.popState, BlockAliases.getAliasBlockId)
+
+    val defaultLeaves = Blocks.OAK_LEAVES.defaultState
+    val defaultGrass = Blocks.GRASS.defaultState
+
+    /**
+     * Called from transformed ShadersMod code.
+     * @see mods.betterfoliage.loader.BetterFoliageTransformer
+     */
+    @JvmStatic fun getBlockStateOverride(state: BlockState, world: ILightReader, pos: BlockPos): BlockState {
+        if (LeafRegistry[state, world, pos] != null) return defaultLeaves
+        if (BlockConfig.crops.matchesClass(state.block)) return defaultGrass
+        return state
+    }
+
+    init {
+        BetterFoliage.log(INFO, "ShadersMod integration is ${if (isAvailable) "enabled" else "disabled" }")
+    }
+
+    inline fun renderAs(ctx: CombinedContext, renderType: BlockRenderType, enabled: Boolean = true, func: ()->Unit) =
+        renderAs(ctx, ctx.state, renderType, enabled, func)
+
+    /** Quads rendered inside this block will use the given block entity data in shader programs. */
+    inline fun renderAs(ctx: CombinedContext, state: BlockState, renderType: BlockRenderType, enabled: Boolean = true, func: ()->Unit) {
+        if (isAvailable && enabled) {
+            val buffer = ctx.renderCtx.renderBuffer
+            val aliasBlockId = BlockAliases.getAliasBlockId.invokeStatic(state)
+            val sVertexBuilder = buffer[BufferBuilder_sVertexBuilder]
+            SVertexBuilder.pushState.invoke(sVertexBuilder, aliasBlockId)
+            func()
+            SVertexBuilder.popState.invoke(sVertexBuilder)
+        } else {
+            func()
+        }
+    }
+
+    /** Quads rendered inside this block will behave as tallgrass blocks in shader programs. */
+    inline fun grass(ctx: CombinedContext, enabled: Boolean = true, func: ()->Unit) =
+        renderAs(ctx, defaultGrass, MODEL, enabled, func)
+
+    /** Quads rendered inside this block will behave as leaf blocks in shader programs. */
+    inline fun leaves(ctx: CombinedContext, enabled: Boolean = true, func: ()->Unit) =
+        renderAs(ctx, defaultLeaves, MODEL, enabled, func)
+}