render system: polygon offset

src/main/java/de/bixilon/minosoft/gui/rendering/system/base/RenderSystem.kt

@@ -41,6 +41,7 @@ interface RenderSystem {
         depthTest: Boolean = true,
         blending: Boolean = false,
         faceCulling: Boolean = true,
+        polygonOffset: Boolean = false,
         depthMask: Boolean = true,
         sourceRGB: BlendingFunctions = BlendingFunctions.ONE,
         destinationRGB: BlendingFunctions = BlendingFunctions.ONE_MINUS_SOURCE_ALPHA,
@@ -48,15 +49,19 @@ interface RenderSystem {
         destinationAlpha: BlendingFunctions = BlendingFunctions.ZERO,
         depth: DepthFunctions = DepthFunctions.LESS,
         clearColor: RGBColor = Colors.TRANSPARENT,
+        polygonOffsetFactor: Float = 0.0f,
+        polygonOffsetUnit: Float = 0.0f,
     ) {
         setBlendFunction(sourceRGB, destinationRGB, sourceAlpha, destinationAlpha)
         this[RenderingCapabilities.DEPTH_TEST] = depthTest
         this[RenderingCapabilities.BLENDING] = blending
         this[RenderingCapabilities.FACE_CULLING] = faceCulling
+        this[RenderingCapabilities.POLYGON_OFFSET] = polygonOffset
         this.depth = depth
         this.depthMask = depthMask
         this.clearColor = clearColor
         shader = null
+        polygonOffset(polygonOffsetFactor, polygonOffsetUnit)
     }
 
     fun enable(capability: RenderingCapabilities)
@@ -110,4 +115,7 @@ interface RenderSystem {
     fun clear(vararg buffers: IntegratedBufferTypes)
 
     fun getErrors(): List<RenderSystemError>
+
+
+    fun polygonOffset(factor: Float, unit: Float)
 }

src/main/java/de/bixilon/minosoft/gui/rendering/system/base/RenderingCapabilities.kt

@@ -1,6 +1,6 @@
 /*
  * Minosoft
- * Copyright (C) 2021 Moritz Zwerger
+ * Copyright (C) 2020-2022 Moritz Zwerger
  *
  * This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
  *
@@ -17,5 +17,6 @@ enum class RenderingCapabilities {
     DEPTH_TEST,
     BLENDING,
     FACE_CULLING,
+    POLYGON_OFFSET,
     ;
 }

src/main/java/de/bixilon/minosoft/gui/rendering/system/opengl/OpenGLRenderSystem.kt

@@ -289,6 +289,16 @@ class OpenGLRenderSystem(
         return errors
     }
 
+    private var polygonOffsetFactor: Float = 0.0f
+    private var polygonOffsetUnit: Float = 0.0f
+    override fun polygonOffset(factor: Float, unit: Float) {
+        if (this.polygonOffsetFactor != factor || this.polygonOffsetUnit != unit) {
+            glPolygonOffset(factor, unit)
+            this.polygonOffsetFactor = factor
+            this.polygonOffsetUnit = unit
+        }
+    }
+
     companion object {
         private val RenderingCapabilities.gl: Int
             get() {
@@ -296,6 +306,7 @@ class OpenGLRenderSystem(
                     RenderingCapabilities.BLENDING -> GL_BLEND
                     RenderingCapabilities.DEPTH_TEST -> GL_DEPTH_TEST
                     RenderingCapabilities.FACE_CULLING -> GL_CULL_FACE
+                    RenderingCapabilities.POLYGON_OFFSET -> GL_POLYGON_OFFSET_FILL
                     else -> throw IllegalArgumentException("OpenGL does not support capability: $this")
                 }
             }

src/main/java/de/bixilon/minosoft/gui/rendering/world/WorldRenderer.kt

@@ -46,6 +46,7 @@ import de.bixilon.minosoft.gui.rendering.renderer.Renderer
 import de.bixilon.minosoft.gui.rendering.renderer.RendererBuilder
 import de.bixilon.minosoft.gui.rendering.system.base.DepthFunctions
 import de.bixilon.minosoft.gui.rendering.system.base.RenderSystem
+import de.bixilon.minosoft.gui.rendering.system.base.RenderingCapabilities
 import de.bixilon.minosoft.gui.rendering.system.base.phases.OpaqueDrawable
 import de.bixilon.minosoft.gui.rendering.system.base.phases.TranslucentDrawable
 import de.bixilon.minosoft.gui.rendering.system.base.phases.TransparentDrawable
@@ -693,6 +694,8 @@ class WorldRenderer(
         }
 
         renderWindow.renderSystem.depth = DepthFunctions.LESS_OR_EQUAL
+        renderWindow.renderSystem[RenderingCapabilities.POLYGON_OFFSET] = true
+        renderWindow.renderSystem.polygonOffset(-2.5f, -2.5f)
         textShader.use()
         for (mesh in visible.text) {
             mesh.draw()

src/main/java/de/bixilon/minosoft/gui/rendering/world/border/WorldBorderRenderer.kt

@@ -57,10 +57,13 @@ class WorldBorderRenderer(
         renderSystem.reset(
             blending = true,
             sourceRGB = BlendingFunctions.SOURCE_ALPHA,
-            destinationRGB = BlendingFunctions.ONE_MINUS_SOURCE_ALPHA,
+            destinationRGB = BlendingFunctions.ONE,
             sourceAlpha = BlendingFunctions.SOURCE_ALPHA,
             destinationAlpha = BlendingFunctions.DESTINATION_ALPHA,
             faceCulling = false,
+            polygonOffset = true,
+            polygonOffsetFactor = -3.0f,
+            polygonOffsetUnit = -3.0f,
         )
         shader.use()
         textureOffset += 0.01f