Main.kt

import kCore.*
import kEnums.KeyboardKey
import kEnums.MouseButton
import kShapes.drawRectangle
import kShapes.drawRectangleRec
import kShapes.drawRectangleV
import kText.drawFPS
import kText.drawText
import kTextures.drawTexture
import kTextures.loadTexture
import kTextures.unloadTexture
import kTypes.*
import kaylib.*
import kotlinx.cinterop.*
import kotlin.random.Random
import kotlin.random.nextInt

const val SCREEN_WIDTH: Int = 1920
const val SCREEN_HEIGHT: Int = 1080
class Bunny(var position: Vector2, var speed: Vector2)

var MAX_BUNNIES = 500000
var MAX_BATCH_ELEMENTS = 8192

fun main() {
    // Initialization
    //--------------------------------------------------------------------------------------
    initWindow(SCREEN_WIDTH, SCREEN_HEIGHT, "raylib [textures] example - bunnymark")

    // Load bunny texture
    val texBunny = loadTexture("resources/wabbit_alpha.png")
    val bunnies = arrayOfNulls<Bunny>(MAX_BUNNIES)
    for (i in 0 until MAX_BUNNIES) {
        bunnies[i] = Bunny(kVector2(0F, 0F), kVector2(0F, 0F))
    }
    var bunniesCount = 0 // Bunnies counter
    setTargetFPS(60)
    //--------------------------------------------------------------------------------------

    // Main game loop
    while (!windowShouldClose) // Detect window close button or ESC key
    {
        // Update
        //----------------------------------------------------------------------------------
        if (isMouseButtonDown(MouseButton.LEFT)) {
            // Create more bunnies
            for (i in 0..99) {
                if (bunniesCount < MAX_BUNNIES) {
                    bunnies[bunniesCount]!!.position = getMousePosition()
                    bunnies[bunniesCount]!!.speed.x = (Random.nextInt(-250, 250) / 60.0f)
                    bunnies[bunniesCount]!!.speed.y = (Random.nextInt(-250, 250) / 60.0f)
                    bunniesCount++
                }
            }
        }

        // Update bunnies
        for (i in 0 until bunniesCount) {
            bunnies[i]!!.position.x += bunnies[i]!!.speed.x
            bunnies[i]!!.position.y += bunnies[i]!!.speed.y
            if (bunnies[i]!!.position.x + texBunny.width / 2.0 > SCREEN_WIDTH ||
                bunnies[i]!!.position.x + texBunny.width / 2.0 < 0
            ) {
                bunnies[i]!!.speed.x *= -1f
            }
            if (bunnies[i]!!.position.y + texBunny.height / 2.0 > SCREEN_HEIGHT ||
                bunnies[i]!!.position.y + texBunny.height / 2.0 - 40 < 0
            ) {
                bunnies[i]!!.speed.y *= -1f
            }
        }
        //----------------------------------------------------------------------------------

        // Draw
        //----------------------------------------------------------------------------------
        beginDrawing()
        clearBackground(rayWhite)
        for (i in 0 until bunniesCount) {
            // NOTE: When internal batch buffer limit is reached (MAX_BATCH_ELEMENTS),
            // a draw call is launched and buffer starts being filled again;
            // before issuing a draw call, updated vertex data from internal CPU buffer is send to GPU...
            // Process of sending data is costly and it could happen that GPU data has not been completely
            // processed for drawing while new data is tried to be sent (updating current in-use buffers)
            // it could generates a stall and consequently a frame drop, limiting the number of drawn bunnies
            drawTexture(
                texBunny,
                bunnies[i]!!.position.x.toInt(),
                bunnies[i]!!.position.y.toInt(),
                rayWhite
            )

        }
        drawRectangle(0, 0, SCREEN_WIDTH, 40, black)
        drawText("bunnies: $bunniesCount", 120, 10, 20, green)
        drawText("batched draw calls: " + 1 + bunniesCount / MAX_BATCH_ELEMENTS, 320, 10, 20, maroon)
        drawFPS(10, 10)
        endDrawing()
        //----------------------------------------------------------------------------------
    }

    // De-Initialization
    //--------------------------------------------------------------------------------------
    unloadTexture(texBunny) // Unload bunny texture
    closeWindow() // Close window and OpenGL context
    //--------------------------------------------------------------------------------------
}