Render GPU output as OpenGL texture

2 files changed, 54 insertions, 16 deletions

diff --git a/src/main/kotlin/gui/EmulationOutputWindow.kt b/src/main/kotlin/gui/EmulationOutputWindow.kt
index 14fe246..3f57d5a 100644
--- a/src/main/kotlin/gui/EmulationOutputWindow.kt
+++ b/src/main/kotlin/gui/EmulationOutputWindow.kt
@@ -1,15 +1,22 @@
 package gui
 
 import glm_.vec2.Vec2
-import imgui.Cond
-import imgui.ImGui
+import imgui.*
 
-fun paintEmulationOutputWindow() {
+fun paintEmulationOutputWindow(frame: TextureID) {
   with(ImGui) {
-    setNextWindowSize(Vec2(640, 576), Cond.FirstUseEver)
+
+    pushStyleVar(StyleVar.WindowPadding, Vec2(0))
+
+    setNextWindowSize(Vec2(640, 596), Cond.FirstUseEver)
     setNextWindowPos(Vec2(620, 10), Cond.FirstUseEver)
-    begin("Emulation output - 4x scale")
-    text("TODO - actually render something...")
+
+    begin("Emulation output - 4x scale", flags_ =  WindowFlag.NoScrollbar or WindowFlag.NoResize)
+
+      image(frame, Vec2(640,576))
+
     end()
+
+    popStyleVar()
   }
 }
\ No newline at end of file
diff --git a/src/main/kotlin/gui/WindowContainer.kt b/src/main/kotlin/gui/WindowContainer.kt
index 8dcd37b..60dc1e4 100644
--- a/src/main/kotlin/gui/WindowContainer.kt
+++ b/src/main/kotlin/gui/WindowContainer.kt
@@ -1,28 +1,36 @@
 package gui
 
+import GameBoy
 import cpu.Cpu
+import gli_.Texture
+import gli_.gli
+import glm_.vec2.Vec2i
 import glm_.vec4.Vec4
 import gln.checkError
+import gln.texture.glDeleteTexture
+import gln.texture.initTexture2d
+import gpu.TestPatternGpu
 import imgui.Context
 import imgui.ImGui
+import imgui.TextureID
 import imgui.destroy
 import imgui.impl.LwjglGL3
 import org.lwjgl.opengl.GL11
+import org.lwjgl.opengl.GL30
 import uno.glfw.GlfwWindow
 import uno.glfw.glfw
+import java.awt.image.BufferedImage
 import java.io.File
 
 class WindowContainer {
 
-  var cpu: Cpu
+  val gameBoy: GameBoy
 
   init {
     glfw.init("3.2")
-    cpu = Cpu()
-    val file = File("src/main/resources/roms/boot-rom.gb")
-    val rom = file.readBytes()
-    cpu.loadRom(rom)
-    //cpu.run()
+
+    gameBoy = GameBoy(Cpu(), TestPatternGpu())
+    gameBoy.loadRom(File("src/main/resources/roms/boot-rom.gb"))
   }
 
   val window = GlfwWindow(1280, 720, "KGB - KotlinGameBoy").apply {
@@ -53,12 +61,14 @@ class WindowContainer {
 
     LwjglGL3.newFrame()
 
+    val (texture, textureId) = createAndRegisterTexture(gameBoy.gpu.getFrame())
+
     with(ImGui) {
       paintDebugWindow()
-      paintEmulationOutputWindow()
-      paintCpuRegisterWindow(cpu.registers)
-      paintRunControlWindow(cpu)
-      paintRamDumpWindow(cpu.ram)
+      paintCpuRegisterWindow(gameBoy.cpu.registers)
+      paintRunControlWindow(gameBoy.cpu)
+      paintRamDumpWindow(gameBoy.cpu.ram)
+      paintEmulationOutputWindow(textureId)
     }
 
     gln.glViewport(window.framebufferSize)
@@ -68,6 +78,27 @@ class WindowContainer {
     ImGui.render()
     LwjglGL3.renderDrawData(ImGui.drawData!!)
 
+    // TODO - render direct to framebuffer rather than creating and destroying texture each frame
+    disposeTexture(texture, textureId)
+
     checkError("mainLoop")
   }
+
+  private fun createAndRegisterTexture(frame: BufferedImage): Pair<Texture, TextureID> {
+    val texture = gli.createTexture(frame)
+    val textureId = initTexture2d {
+      minFilter = linear
+      magFilter = linear
+      GL30.glPixelStorei(GL30.GL_UNPACK_ROW_LENGTH, 0)
+      image(GL30.GL_RGB, Vec2i(640,576), GL30.GL_RGB, GL30.GL_UNSIGNED_BYTE, texture.data())
+    }
+
+    return Pair(texture, textureId)
+  }
+
+  private fun disposeTexture(texture: Texture, textureID: TextureID) {
+    glDeleteTexture(textureID)
+    texture.dispose()
+  }
+
 }
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