ref: buffer orphaning over mapping

Author: emyfops

common/src/main/kotlin/com/lambda/graphics/buffer/IBuffer.kt

@@ -144,16 +144,35 @@ interface IBuffer {
         return null
     }
 
+    /**
+     * Allocates a region of memory for the buffer
+     * This function handles the buffer binding
+     *
+     * @param data The data to put in the new allocated buffer
+     */
+    fun allocate(data: ByteBuffer): Throwable? {
+        // FixMe: If access contains any of GL_MAP_PERSISTENT_BIT or GL_MAP_COHERENT_BIT and the buffer was not initialized using glBufferStorage, glMapBufferRange will fail
+        if (!bufferValid(target))
+            return IllegalArgumentException("Target is not valid. Refer to the table in the documentation")
+
+        if (!bufferUsageValid(usage))
+            return IllegalArgumentException("Buffer usage is invalid")
+
+        bind()
+        glBufferData(target, data, usage)
+        bind(0)
+
+        return null
+    }
+
     /**
      * Grows the backing buffers
-     * This function should not be called frequently
+     * This function handles the buffer binding
      *
      * @param size The size of the new buffer
      */
-    fun grow(size: Long): Throwable? {
-        if (
-            size < 0
-        ) return IllegalArgumentException("Invalid size parameter: $size")
+    fun allocate(size: Long): Throwable? {
+        if (size < 0) return IllegalArgumentException("Invalid size parameter: $size")
 
         // FixMe: If access contains any of GL_MAP_PERSISTENT_BIT or GL_MAP_COHERENT_BIT and the buffer was not initialized using glBufferStorage, glMapBufferRange will fail
         if (!bufferValid(target))
@@ -162,16 +181,9 @@ interface IBuffer {
         if (!bufferUsageValid(usage))
             return IllegalArgumentException("Buffer usage is invalid")
 
-        bufferIds.forEach { bufferId ->
-            // Orphan the buffer and allocate a new one
-            bind(bufferId)
-
-            // Only resize if the new size is bigger than the bound buffer capacity
-            if (size > glGetBufferParameteri(target, GL_BUFFER_SIZE))
-                glBufferData(target, size, usage)
-
-            bind(0) // Don't forget to unbind to avoid accidental buffer modification
-        }
+        bind()
+        glBufferData(target, size, usage)
+        bind(0)
 
         return null
     }
@@ -202,14 +214,7 @@ interface IBuffer {
 
         if (
             offset + size > glGetBufferParameteri(target, GL_BUFFER_SIZE)
-        ) return IllegalArgumentException(
-            "Out of bound mapping: $offset + $size > ${
-                glGetBufferParameteri(
-                    target,
-                    GL_BUFFER_SIZE
-                )
-            }"
-        )
+        ) return IllegalArgumentException("Out of bound mapping: $offset + $size > ${glGetBufferParameteri(target, GL_BUFFER_SIZE)}")
 
         if (
             glGetBufferParameteri(target, GL_BUFFER_MAPPED)
@@ -222,11 +227,11 @@ interface IBuffer {
         ) return IllegalArgumentException("Neither GL_MAP_READ_BIT nor GL_MAP_WRITE_BIT is set")
 
         if (
-            access and GL_MAP_READ_BIT != 0 &&
+            access and GL_MAP_READ_BIT != 0         &&
             (access and GL_MAP_INVALIDATE_RANGE_BIT == 0 ||
-                    access and GL_MAP_INVALIDATE_BUFFER_BIT == 0 ||
-                    access and GL_MAP_UNSYNCHRONIZED_BIT == 0
-                    )
+            access and GL_MAP_INVALIDATE_BUFFER_BIT == 0 ||
+            access and GL_MAP_UNSYNCHRONIZED_BIT    == 0
+            )
         ) return IllegalArgumentException("GL_MAP_READ_BIT is set and any of GL_MAP_INVALIDATE_RANGE_BIT, GL_MAP_INVALIDATE_BUFFER_BIT or GL_MAP_UNSYNCHRONIZED_BIT is set.")
 
         // Map the buffer into the client's memory

common/src/main/kotlin/com/lambda/graphics/buffer/VertexPipeline.kt

@@ -138,8 +138,6 @@ class VertexPipeline(
         val newVertices = byteBuffer(newSize)
         Memory.copy(address(vertices), address(newVertices), offset)
 
-        vbo.grow(newSize.toLong())
-
         vertices = newVertices
         verticesPointer = address(vertices)
         verticesPosition = verticesPointer + offset
@@ -154,8 +152,6 @@ class VertexPipeline(
 
         Memory.copy(address(indices), address(newIndices), indicesCount * 4L)
 
-        ebo.grow(newSize.toLong())
-
         indices = newIndices
         indicesPointer = address(indices)
     }

common/src/main/kotlin/com/lambda/graphics/buffer/pixel/PixelBuffer.kt

@@ -122,7 +122,7 @@ class PixelBuffer(
         glBindTexture(GL_TEXTURE_2D, 0)
 
         // Fill the buffers with null data to allocate the memory spaces
-        grow(size)
+        allocate(size)
     }
 
     companion object {

common/src/main/kotlin/com/lambda/graphics/buffer/vertex/ElementBuffer.kt

@@ -35,18 +35,7 @@ class ElementBuffer(mode: VertexMode) : IBuffer {
     override fun upload(
         data: ByteBuffer,
         offset: Long,
-    ): Throwable? {
-        // Bind the buffer
-        bind()
-
-        // Map the buffer into the client's memory
-        val error = map(offset, data.limit().toLong(), data::putTo)
-
-        // Unbind
-        bind(0)
-
-        return error
-    }
+    ): Throwable? = allocate(data)
 
     override fun bind(id: Int) {
         if (id != 0) prevIbo = lastIbo
@@ -56,8 +45,7 @@ class ElementBuffer(mode: VertexMode) : IBuffer {
     }
 
     init {
-        // Fill the buffer with null data
-        grow(mode.indicesCount * 2L.kibibyte)
+        allocate(mode.indicesCount * 2L.kibibyte)
     }
 
     companion object {

common/src/main/kotlin/com/lambda/graphics/buffer/vertex/VertexArray.kt

@@ -41,7 +41,7 @@ class VertexArray : IBuffer {
         offset: Long,
     ): Throwable? = throw UnsupportedOperationException("Data cannot be uploaded to a vertex array object")
 
-    override fun grow(size: Long) = throw UnsupportedOperationException("Cannot grow a vertex array object")
+    override fun allocate(size: Long) = throw UnsupportedOperationException("Cannot grow a vertex array object")
 
     override fun bind(id: Int) {
         glBindVertexArray(id); BufferRenderer.currentVertexBuffer = null

common/src/main/kotlin/com/lambda/graphics/buffer/vertex/VertexBuffer.kt

@@ -29,34 +29,19 @@ class VertexBuffer(
     mode: VertexMode,
     attributes: VertexAttrib.Group,
 ) : IBuffer {
-    override val buffers: Int = 2
+    override val buffers: Int = 1
     override val usage: Int = GL_DYNAMIC_DRAW
     override val target: Int = GL_ARRAY_BUFFER
     override val access: Int = GL_MAP_WRITE_BIT
     override var index = 0
-    override val bufferIds = IntArray(buffers).apply { glGenBuffers(this) }
+    override val bufferIds = intArrayOf(glGenBuffers())
 
-    override fun upload(data: ByteBuffer, offset: Long): Throwable? {
-        // Bind the buffer
-        bind()
-
-        // Update the buffer data
-        val error = map(offset, data.limit().toLong(), data::putTo)
-
-        // We need to swap the index because our memory mapping requires
-        // synchronization between the GPU and CPU
-        // The GL_MAP_COHERENT bit tells OpenGL to synchronize the transfer
-        // to the buffer
-        swap()
-
-        // Unbind
-        bind(0)
-
-        return error
-    }
+    override fun upload(
+        data: ByteBuffer,
+        offset: Long,
+    ): Throwable? = allocate(data)
 
     init {
-        // Fill the buffer with null data
-        grow(attributes.stride * mode.indicesCount * 1L.kibibyte)
+        allocate(attributes.stride * mode.indicesCount * 1L.kibibyte)
     }
 }

common/src/main/kotlin/com/lambda/util/extension/Other.kt

@@ -17,6 +17,25 @@
 
 package com.lambda.util.extension
 
+import kotlin.contracts.ExperimentalContracts
+import kotlin.contracts.InvocationKind
+import kotlin.contracts.contract
+
+/**
+ * Executes the given block only if the object receiver is null
+ * Opposite of `Any?.let {}`
+ */
+@OptIn(ExperimentalContracts::class)
+inline fun <T> T?.ifNull(block: () -> Unit): T? {
+    contract {
+        callsInPlace(block, InvocationKind.AT_MOST_ONCE)
+    }
+
+    if (this == null) block()
+
+    return this
+}
+
 val Class<*>.isObject: Boolean
     get() = declaredFields.any { it.name == "INSTANCE" }
 

common/src/main/kotlin/com/lambda/util/math/MathUtils.kt

@@ -80,19 +80,7 @@ object MathUtils {
         return nextDouble(min, max)
     }
 
-    /**
-     * @return The smallest power of two that is greater than or equal to the input integer.
-     */
-    fun Int.ceilToPOT(): Int {
-        var i = this
-        i--
-        i = i or (i shr 1)
-        i = i or (i shr 2)
-        i = i or (i shr 4)
-        i = i or (i shr 8)
-        i = i or (i shr 16)
-        return ++i
-    }
+    fun Int.nextPowerOf2() = 2f.pow(ceil(log2(toFloat()))).toInt()
 
     inline val Int.sq: Int get() = this * this
 }