Add GPU interface and implementation which returns a test pattern

3 files changed, 71 insertions, 0 deletions

diff --git a/src/main/kotlin/GameBoy.kt b/src/main/kotlin/GameBoy.kt
new file mode 100644
index 0000000..7c8dfdc
--- /dev/null
+++ b/src/main/kotlin/GameBoy.kt
@@ -0,0 +1,10 @@
+import cpu.Cpu
+import gpu.Gpu
+import java.io.File
+
+class GameBoy(val cpu: Cpu, val gpu: Gpu) {
+
+  fun loadRom(file: File) {
+    this.cpu.loadRom(file.readBytes())
+  }
+}
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diff --git a/src/main/kotlin/gpu/Gpu.kt b/src/main/kotlin/gpu/Gpu.kt
new file mode 100644
index 0000000..db95c03
--- /dev/null
+++ b/src/main/kotlin/gpu/Gpu.kt
@@ -0,0 +1,9 @@
+package gpu
+
+import java.awt.Color
+import java.awt.image.BufferedImage
+
+interface Gpu {
+  fun setPixel(x: Int, y: Int, colour: Color)
+  fun getFrame(): BufferedImage
+}
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diff --git a/src/main/kotlin/gpu/TestPatternGpu.kt b/src/main/kotlin/gpu/TestPatternGpu.kt
new file mode 100644
index 0000000..6976426
--- /dev/null
+++ b/src/main/kotlin/gpu/TestPatternGpu.kt
@@ -0,0 +1,52 @@
+package gpu
+
+import java.awt.Color
+import java.awt.image.BufferedImage
+import java.io.File
+import javax.imageio.ImageIO
+
+class TestPatternGpu : Gpu {
+
+  private val SCALING_FACTOR = 4
+
+  private val frame = BufferedImage(160 * SCALING_FACTOR, 144 * SCALING_FACTOR, BufferedImage.TYPE_INT_RGB)
+
+  private var lastColour = Color.BLACK
+
+  override fun setPixel(x: Int, y: Int, colour: Color) {
+    (0 until SCALING_FACTOR).forEach { xOffset ->
+      (0 until SCALING_FACTOR).forEach { yOffset ->
+        frame.setRGB((x * SCALING_FACTOR) + xOffset, (y * SCALING_FACTOR) + yOffset, colour.rgb)
+      }
+    }
+  }
+
+  override fun getFrame(): BufferedImage {
+
+    (0 until 144).forEach { y ->
+
+      if(y % 4 == 0) {
+        swapColour()
+      }
+
+      (0 until 160).forEach { x ->
+
+        if(x % 4 == 0) {
+          swapColour()
+        }
+
+        setPixel(x, y, lastColour)
+      }
+    }
+
+    return frame
+  }
+
+  private fun swapColour() {
+    lastColour = if(lastColour == Color.BLACK) {
+      Color.WHITE
+    } else {
+      Color.BLACK
+    }
+  }
+}
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