gpu: add anisotropic filtering

runelite-client/src/main/java/net/runelite/client/plugins/gpu/GLUtil.java

@@ -31,6 +31,7 @@ class GLUtil
 	private static final int ERR_LEN = 1024;
 
 	private static final int[] buf = new int[1];
+	private static final float[] fbuf = new float[1];
 
 	static int glGetInteger(GL4 gl, int pname)
 	{
@@ -38,6 +39,12 @@ class GLUtil
 		return buf[0];
 	}
 
+	static float glGetFloat(GL4 gl, int pname)
+	{
+		gl.glGetFloatv(pname, fbuf, 0);
+		return fbuf[0];
+	}
+
 	static int glGetShader(GL4 gl, int shader, int pname)
 	{
 		gl.glGetShaderiv(shader, pname, buf, 0);

runelite-client/src/main/java/net/runelite/client/plugins/gpu/GpuPlugin.java

@@ -243,6 +243,7 @@ public class GpuPlugin extends Plugin implements DrawCallbacks
 	private int lastStretchedCanvasWidth;
 	private int lastStretchedCanvasHeight;
 	private AntiAliasingMode lastAntiAliasingMode;
+	private int lastAnisotropicFilteringLevel = -1;
 
 	private int centerX;
 	private int centerY;
@@ -1106,6 +1107,15 @@ public class GpuPlugin extends Plugin implements DrawCallbacks
 			int renderViewportHeight = viewportHeight;
 			int renderViewportWidth = viewportWidth;
 
+			// Setup anisotropic filtering
+			final int anisotropicFilteringLevel = config.anisotropicFilteringLevel();
+
+			if (textureArrayId != -1 && lastAnisotropicFilteringLevel != anisotropicFilteringLevel)
+			{
+				textureManager.setAnisotropicFilteringLevel(textureArrayId, anisotropicFilteringLevel, gl);
+				lastAnisotropicFilteringLevel = anisotropicFilteringLevel;
+			}
+
 			if (client.isStretchedEnabled())
 			{
 				Dimension dim = client.getStretchedDimensions();

runelite-client/src/main/java/net/runelite/client/plugins/gpu/GpuPluginConfig.java

@@ -108,4 +108,19 @@ public interface GpuPluginConfig extends Config
 	{
 		return true;
 	}
+
+	@Range(
+		min = 0,
+		max = 16
+	)
+	@ConfigItem(
+		keyName = "anisotropicFilteringLevel",
+		name = "Anisotropic Filtering",
+		description = "Configures the anisotropic filtering level.",
+		position = 7
+	)
+	default int anisotropicFilteringLevel()
+	{
+		return 0;
+	}
 }

runelite-client/src/main/java/net/runelite/client/plugins/gpu/TextureManager.java

@@ -51,7 +51,7 @@ class TextureManager
 
 		int textureArrayId = GLUtil.glGenTexture(gl);
 		gl.glBindTexture(gl.GL_TEXTURE_2D_ARRAY, textureArrayId);
-		gl.glTexStorage3D(gl.GL_TEXTURE_2D_ARRAY, 1, gl.GL_RGBA8, TEXTURE_SIZE, TEXTURE_SIZE, textures.length);
+		gl.glTexStorage3D(gl.GL_TEXTURE_2D_ARRAY, 8, gl.GL_RGBA8, TEXTURE_SIZE, TEXTURE_SIZE, textures.length);
 
 		gl.glTexParameteri(gl.GL_TEXTURE_2D_ARRAY, gl.GL_TEXTURE_MIN_FILTER, gl.GL_NEAREST);
 		gl.glTexParameteri(gl.GL_TEXTURE_2D_ARRAY, gl.GL_TEXTURE_MAG_FILTER, gl.GL_NEAREST);
@@ -68,11 +68,40 @@ class TextureManager
 
 		gl.glActiveTexture(gl.GL_TEXTURE1);
 		gl.glBindTexture(gl.GL_TEXTURE_2D_ARRAY, textureArrayId);
+		gl.glGenerateMipmap(gl.GL_TEXTURE_2D_ARRAY);
 		gl.glActiveTexture(gl.GL_TEXTURE0);
 
 		return textureArrayId;
 	}
 
+	void setAnisotropicFilteringLevel(int textureArrayId, int level, GL4 gl)
+	{
+		gl.glBindTexture(gl.GL_TEXTURE_2D_ARRAY, textureArrayId);
+
+		//level = 0 means no mipmaps and no anisotropic filtering
+		if (level == 0)
+		{
+			gl.glTexParameteri(gl.GL_TEXTURE_2D_ARRAY, gl.GL_TEXTURE_MIN_FILTER, gl.GL_NEAREST);
+		}
+		//level = 1 means with mipmaps but without anisotropic filtering GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT defaults to 1.0 which is off
+		//level > 1 enables anisotropic filtering. It's up to the vendor what the values mean
+		//Even if anisotropic filtering isn't supported, mipmaps will be enabled with any level >= 1
+		else
+		{
+			// Set on GL_NEAREST_MIPMAP_LINEAR (bilinear filtering with mipmaps) since the pixel nature of the game means that nearest filtering
+			// looks best for objects up close but allows linear filtering to resolve possible aliasing and noise with mipmaps from far away objects.
+			gl.glTexParameteri(gl.GL_TEXTURE_2D_ARRAY, gl.GL_TEXTURE_MIN_FILTER, gl.GL_NEAREST_MIPMAP_LINEAR);
+		}
+
+		if (gl.isExtensionAvailable("GL_EXT_texture_filter_anisotropic"))
+		{
+			final float maxSamples = GLUtil.glGetFloat(gl, gl.GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT);
+			//Clamp from 1 to max GL says it supports.
+			final float anisoLevel = Math.max(1, Math.min(maxSamples, level));
+			gl.glTexParameterf(gl.GL_TEXTURE_2D_ARRAY, gl.GL_TEXTURE_MAX_ANISOTROPY_EXT, anisoLevel);
+		}
+	}
+
 	void freeTextureArray(GL4 gl, int textureArrayId)
 	{
 		GLUtil.glDeleteTexture(gl, textureArrayId);