fbo: rename ColorAttachments to TextureAttachments and add depth & st…

…encil support (#229)
littlektframework · Jan 31, 2024 · 8dbd6f7 · 8dbd6f7
1 parent ab8f640
commit 8dbd6f7
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Showing 5 changed files with 49 additions and 27 deletions.
diff --git a/core/src/commonMain/kotlin/com/lehaine/littlekt/graph/node/FrameBufferNode.kt b/core/src/commonMain/kotlin/com/lehaine/littlekt/graph/node/FrameBufferNode.kt
@@ -101,8 +101,8 @@ open class FrameBufferNode : CanvasLayer() {
             fbo = FrameBuffer(
                 width,
                 height,
-                colorAttachments = listOf(
-                    FrameBuffer.ColorAttachment(
+                textureAttachments = listOf(
+                    FrameBuffer.TextureAttachment(
                         minFilter = TexMinFilter.NEAREST,
                         magFilter = TexMagFilter.NEAREST
                     )

diff --git a/core/src/commonMain/kotlin/com/lehaine/littlekt/graphics/FrameBuffer.kt b/core/src/commonMain/kotlin/com/lehaine/littlekt/graphics/FrameBuffer.kt
@@ -3,7 +3,7 @@ package com.lehaine.littlekt.graphics
 import com.lehaine.littlekt.Context
 import com.lehaine.littlekt.Disposable
 import com.lehaine.littlekt.file.createIntBuffer
-import com.lehaine.littlekt.graphics.FrameBuffer.ColorAttachment
+import com.lehaine.littlekt.graphics.FrameBuffer.TextureAttachment
 import com.lehaine.littlekt.graphics.gl.*
 import com.lehaine.littlekt.math.MutableVec4i
 import kotlin.contracts.ExperimentalContracts
@@ -14,7 +14,7 @@ import kotlin.contracts.contract
  * Encapsulates OpenGL frame buffer objects.
  * @param width the width of the framebuffer in pixels
  * @param height the height of the framebuffer in pixels
- * @param colorAttachments the list of [ColorAttachment] to attach to the FrameBuffer.
+ * @param textureAttachments the list of [TextureAttachment] to attach to the FrameBuffer.
  * @param hasDepth whether to attach a depth buffer. Defaults to false.
  * @param hasStencil whether to attach a stencil buffer. Defaults to false.
  * @param hasPackedDepthStencil whether to attach a packed depth/stencil buffer. Defaults to false.
@@ -24,7 +24,7 @@ import kotlin.contracts.contract
 open class FrameBuffer(
     val width: Int,
     val height: Int,
-    val colorAttachments: List<ColorAttachment> = listOf(ColorAttachment()),
+    val textureAttachments: List<TextureAttachment> = listOf(TextureAttachment()),
     val hasDepth: Boolean = false,
     val hasStencil: Boolean = false,
     var hasPackedDepthStencil: Boolean = false,
@@ -55,7 +55,7 @@ open class FrameBuffer(
     ) : this(
         width,
         height,
-        listOf(ColorAttachment(format, minFilter, magFilter, wrap)),
+        listOf(TextureAttachment(format, minFilter, magFilter, wrap)),
         hasDepth,
         hasStencil,
         hasPackedDepthStencil
@@ -67,13 +67,19 @@ open class FrameBuffer(
      * @param minFilter texture min filter
      * @param magFilter texture mag filter
      * @param wrap format for UV texture wrap
+     * @param isDepth `true` if texture depth attachment; `false` otherwise
+     * @param isStencil `true` if texture is a stencil attachment; `false` otherwise
      */
-    class ColorAttachment(
+    data class TextureAttachment(
         val format: Pixmap.Format = Pixmap.Format.RGBA8888,
         val minFilter: TexMinFilter = TexMinFilter.LINEAR,
         val magFilter: TexMagFilter = TexMagFilter.LINEAR,
         val wrap: TexWrap = TexWrap.CLAMP_TO_EDGE,
-    )
+        val isDepth: Boolean = false,
+        val isStencil: Boolean = false,
+    ) {
+        val isColorTexture: Boolean get() = !isDepth && !isStencil
+    }
 
     /**
      * Gets set when the frame buffer is prepared by the application
@@ -139,29 +145,45 @@ open class FrameBuffer(
             }
         }
 
-        colorAttachments.forEachIndexed { i, colorAttachment ->
+        textureAttachments.forEachIndexed { i, attachment ->
             _textures += Texture(
                 GLTextureData(
                     width,
                     height,
                     0,
-                    colorAttachment.format.glFormat,
-                    colorAttachment.format.glFormat,
-                    colorAttachment.format.glType
+                    attachment.format.glFormat,
+                    attachment.format.glFormat,
+                    attachment.format.glType
                 )
             ).apply {
-                minFilter = colorAttachment.minFilter
-                magFilter = colorAttachment.magFilter
-                uWrap = colorAttachment.wrap
-                vWrap = colorAttachment.wrap
+                minFilter = attachment.minFilter
+                magFilter = attachment.magFilter
+                uWrap = attachment.wrap
+                vWrap = attachment.wrap
             }.also { texture ->
                 texture.prepare(context) // preparing the texture will also bind it
-                gl.frameBufferTexture2D(
-                    FrameBufferRenderBufferAttachment.COLOR_ATTACHMENT(i),
-                    texture.glTexture
-                        ?: throw RuntimeException("FrameBuffer failed on attempting to add color attachment($i)!"),
-                    0
-                )
+                if (attachment.isColorTexture) {
+                    gl.frameBufferTexture2D(
+                        FrameBufferRenderBufferAttachment.COLOR_ATTACHMENT(i),
+                        texture.glTexture
+                            ?: throw RuntimeException("FrameBuffer failed on attempting to add color attachment($i)!"),
+                        0
+                    )
+                } else if (attachment.isDepth) {
+                    gl.frameBufferTexture2D(
+                        FrameBufferRenderBufferAttachment.DEPTH_ATTACHMENT,
+                        texture.glTexture
+                            ?: throw RuntimeException("FrameBuffer failed on attempting to add depth attachment!"),
+                        0
+                    )
+                } else if (attachment.isStencil) {
+                    gl.frameBufferTexture2D(
+                        FrameBufferRenderBufferAttachment.STENCIL_ATTACHMENT,
+                        texture.glTexture
+                            ?: throw RuntimeException("FrameBuffer failed on attempting to add stencil attachment!"),
+                        0
+                    )
+                }
             }
         }
 

diff --git a/samples/src/commonMain/kotlin/com/lehaine/littlekt/samples/FBOMultiTargetTest.kt b/samples/src/commonMain/kotlin/com/lehaine/littlekt/samples/FBOMultiTargetTest.kt
@@ -47,8 +47,8 @@ class FBOMultiTargetTest(context: Context) : ContextListener(context) {
             240,
             135,
             listOf(
-                FrameBuffer.ColorAttachment(minFilter = TexMinFilter.NEAREST, magFilter = TexMagFilter.NEAREST),
-                FrameBuffer.ColorAttachment(minFilter = TexMinFilter.NEAREST, magFilter = TexMagFilter.NEAREST)
+                FrameBuffer.TextureAttachment(minFilter = TexMinFilter.NEAREST, magFilter = TexMagFilter.NEAREST),
+                FrameBuffer.TextureAttachment(minFilter = TexMinFilter.NEAREST, magFilter = TexMagFilter.NEAREST)
             )
         ).also {
             it.prepare(context)

diff --git a/samples/src/commonMain/kotlin/com/lehaine/littlekt/samples/FBOTest.kt b/samples/src/commonMain/kotlin/com/lehaine/littlekt/samples/FBOTest.kt
@@ -35,7 +35,7 @@ class FBOTest(context: Context) : ContextListener(context) {
         val fbo = FrameBuffer(
             240,
             135,
-            listOf(FrameBuffer.ColorAttachment(minFilter = TexMinFilter.NEAREST, magFilter = TexMagFilter.NEAREST))
+            listOf(FrameBuffer.TextureAttachment(minFilter = TexMinFilter.NEAREST, magFilter = TexMagFilter.NEAREST))
         ).also {
             it.prepare(context)
         }

diff --git a/samples/src/commonMain/kotlin/com/lehaine/littlekt/samples/PixelSmoothCameraTest.kt b/samples/src/commonMain/kotlin/com/lehaine/littlekt/samples/PixelSmoothCameraTest.kt
@@ -56,7 +56,7 @@ class PixelSmoothCameraTest(context: Context) : ContextListener(context) {
         var fbo = FrameBuffer(
             1,
             1,
-            listOf(FrameBuffer.ColorAttachment(minFilter = TexMinFilter.NEAREST, magFilter = TexMagFilter.NEAREST))
+            listOf(FrameBuffer.TextureAttachment(minFilter = TexMinFilter.NEAREST, magFilter = TexMagFilter.NEAREST))
         ).also {
             it.prepare(this)
         }
@@ -76,7 +76,7 @@ class PixelSmoothCameraTest(context: Context) : ContextListener(context) {
             fbo = FrameBuffer(
                 pxWidth.nextPowerOfTwo,
                 pxHeight.nextPowerOfTwo,
-                listOf(FrameBuffer.ColorAttachment(minFilter = TexMinFilter.NEAREST, magFilter = TexMagFilter.NEAREST))
+                listOf(FrameBuffer.TextureAttachment(minFilter = TexMinFilter.NEAREST, magFilter = TexMagFilter.NEAREST))
             ).also {
                 it.prepare(this)
             }