[WIP] major rewrite, grass and leaves working already

src/main/kotlin/mods/betterfoliage/render/lighting/VanillaVertexLighter.kt

@@ -0,0 +1,133 @@
+package mods.betterfoliage.render.lighting
+
+import mods.betterfoliage.render.old.HalfBakedQuad
+import mods.betterfoliage.util.Double3
+import mods.betterfoliage.util.EPSILON
+import mods.betterfoliage.util.minBy
+import net.minecraft.client.renderer.color.BlockColors
+import net.minecraft.util.Direction
+import net.minecraft.util.Direction.*
+import net.minecraft.util.Direction.Axis
+import net.minecraftforge.client.model.pipeline.LightUtil
+import kotlin.math.abs
+
+class VanillaQuadLighting {
+    val packedLight = IntArray(4)
+    val colorMultiplier = FloatArray(4)
+    val tint = FloatArray(3)
+
+    val calc = VanillaAoCalculator()
+    lateinit var blockColors: BlockColors
+
+    fun updateBlockTint(tintIndex: Int) {
+        if (tintIndex == -1) {
+            tint[0] = 1.0f; tint[1] = 1.0f; tint[2] = 1.0f
+        } else {
+            val state = calc.world.getBlockState(calc.blockPos)
+            blockColors.getColor(state, calc.world, calc.blockPos, tintIndex).let { blockTint ->
+                tint[0] = (blockTint shr 16 and 255).toFloat() / 255.0f
+                tint[1] = (blockTint shr 8 and 255).toFloat() / 255.0f
+                tint[2] = (blockTint and 255).toFloat() / 255.0f
+            }
+        }
+    }
+
+    fun applyDiffuseLighting(face: Direction) {
+        val factor = LightUtil.diffuseLight(face)
+        tint[0] *= factor; tint[1] *= factor; tint[2] *= factor
+    }
+}
+
+abstract class VanillaVertexLighter {
+    abstract fun updateLightmapAndColor(quad: HalfBakedQuad, lighting: VanillaQuadLighting)
+
+    inline fun VanillaQuadLighting.updateWithCornerAo(quad: HalfBakedQuad, func: (Double3)->Int?) {
+        quad.raw.verts.forEachIndexed { idx, vertex ->
+            func(vertex.xyz)?.let {
+                packedLight[idx] = calc.aoData[it].packedLight
+                colorMultiplier[idx] = calc.aoData[it].colorMultiplier
+            }
+        }
+    }
+}
+
+object VanillaFullBlockLighting : VanillaVertexLighter() {
+    override fun updateLightmapAndColor(quad: HalfBakedQuad, lighting: VanillaQuadLighting) {
+        // TODO bounds checking
+        val face = quad.raw.face()
+        lighting.calc.fillLightData(face, true)
+        lighting.updateWithCornerAo(quad) { nearestCornerOnFace(it, face) }
+        lighting.updateBlockTint(quad.baked.tintIndex)
+        if (quad.baked.shouldApplyDiffuseLighting()) lighting.applyDiffuseLighting(face)
+    }
+}
+
+object RoundLeafLighting : VanillaVertexLighter() {
+    override fun updateLightmapAndColor(quad: HalfBakedQuad, lighting: VanillaQuadLighting) {
+        val angles = getAngles45(quad)?.let { normalFaces ->
+            lighting.calc.fillLightData(normalFaces.first)
+            lighting.calc.fillLightData(normalFaces.second)
+            if (normalFaces.first != UP && normalFaces.second != UP) lighting.calc.fillLightData(UP)
+            lighting.updateWithCornerAo(quad) { vertex ->
+                val isUp = vertex.y > 0.5f
+                val cornerUndir = AoSideHelper.getCornerUndir(vertex.x, vertex.y, vertex.z)
+                val preferredFace = if (isUp) UP else normalFaces.minBy { faceDistance(it, vertex) }
+                AoSideHelper.boxCornersDirFromUndir[preferredFace.ordinal][cornerUndir]
+            }
+            lighting.updateBlockTint(quad.baked.tintIndex)
+        }
+    }
+}
+
+class LightingPreferredFace(val face: Direction) : VanillaVertexLighter() {
+    override fun updateLightmapAndColor(quad: HalfBakedQuad, lighting: VanillaQuadLighting) {
+        lighting.calc.fillLightData(face)
+        lighting.updateWithCornerAo(quad) { nearestCornerOnFace(it, face) }
+        lighting.updateBlockTint(quad.baked.tintIndex)
+    }
+}
+
+/**
+ * Return the directed box corner index for the corner nearest the given vertex,
+ * which is on the given face. May return null if the vertex is closest to
+ * one of the opposite 4 corners
+ */
+fun nearestCornerOnFace(pos: Double3, face: Direction): Int? {
+    val cornerUndir = AoSideHelper.getCornerUndir(pos.x, pos.y, pos.z)
+    return AoSideHelper.boxCornersDirFromUndir[face.ordinal][cornerUndir]
+}
+
+/**
+ * If the quad normal approximately bisects 2 axes at a 45 degree angle,
+ * and is approximately perpendicular to the third, returns the 2 directions
+ * the quad normal points towards.
+ * Returns null otherwise.
+ */
+fun getAngles45(quad: HalfBakedQuad): Pair<Direction, Direction>? {
+    val normal = quad.raw.normal
+    // one of the components must be close to zero
+    val zeroAxis = when {
+        abs(normal.x) < EPSILON -> Axis.X
+        abs(normal.y) < EPSILON -> Axis.Y
+        abs(normal.z) < EPSILON -> Axis.Z
+        else -> return null
+    }
+    // the other two must be of similar magnitude
+    val diff = when(zeroAxis) {
+        Axis.X -> abs(abs(normal.y) - abs(normal.z))
+        Axis.Y -> abs(abs(normal.x) - abs(normal.z))
+        Axis.Z -> abs(abs(normal.x) - abs(normal.y))
+    }
+    if (diff > EPSILON) return null
+    return when(zeroAxis) {
+        Axis.X -> Pair(if (normal.y > 0.0f) UP else DOWN, if (normal.z > 0.0f) SOUTH else NORTH)
+        Axis.Y -> Pair(if (normal.x > 0.0f) EAST else WEST, if (normal.z > 0.0f) SOUTH else NORTH)
+        Axis.Z -> Pair(if (normal.x > 0.0f) EAST else WEST, if (normal.y > 0.0f) UP else DOWN)
+    }
+}
+
+fun faceDistance(face: Direction, pos: Double3) = when(face) {
+    WEST -> pos.x; EAST -> 1.0 - pos.x
+    DOWN -> pos.y; UP -> 1.0 - pos.y
+    NORTH -> pos.z; SOUTH -> 1.0 - pos.z
+}