featurea game engine minimalism demonstration

game.kt

@file:Dependency("featurea:app:1.0")
@file:Dependency("featurea:graphics:1.0")
@file:Dependency("featurea:input:1.0")
@file:Dependency("featurea:pbr:1.0")

package game

import featurea.app.*
import featurea.graphics.*
import featurea.input.*
import featurea.pbr.*
import featurea.runtime.*
import featurea.utils.Color.orangeColor

val artifact = Artifact {
    include(featurea.graphics.artifact)
    include(featurea.input.artifact)
}

fun bootstrap(init: Runnable) = runApplication(include = game.artifact, init)

fun main() = bootstrap {
    val app: Application = import()
    val gl: Opengl = import()
    val graphics: Graphics = import()
    val loader: Loader = import()

    app.delegate = ApplicationDelegate {
        init {
            loader.load(marioPng)
            loader.load(pbrShader)
            loader.load(simpleShader)
            loader.load(sponzaGlb)
            loader.load(quadIndices)
            loader.load(quadVertices)
        }
        update {
            graphics.clear(orangeColor)

            // mario.png
            graphics.drawImage(marioPng, x = 30, y = 30, width = 100, height = 100)

            // simple.shader
            gl.useProgram(simpleShader)
            gl.useBuffer(quadVertices)
            gl.uniforms["time"] = app.time
            gl.drawTriangles(quadIndices)

            // sponza.glb
            gl.useProgram(pbrShader)
            gl.drawModel(sponzaGlb)
        }
    }
}

/*content*/

const val marioPng = "https://images.com/mario.png"
const val sponzaGlb ="https://models.com/sponza.glb"

val quadVertices: VertexBuffer = VertexBuffer(
    -1.0f,  1.0f,
    -1.0f, -1.0f,
     1.0f, -1.0f,
     1.0f,  1.0f,
)

val quadIndices: IndexBuffer = IndexBuffer(
    0, 1, 2,
    1, 2, 3,
)

const val simpleShader: Program = Program("""

#shader vertex(vec2 position)

void main() {
    outPosition = vec4(position, 0.0, 1.0)
}

#shader pixel

float time;

void main() {
    outColor = vec4(0.2, sin(totalTime) * 0.5 + 0.5, 0.8, 1.0);
}

""")