From ba97c99f983f52d98d7a7550dfbd505fe3be8f84 Mon Sep 17 00:00:00 2001
From: Bob <ytinasni@gmail.com>
Date: Thu, 11 Nov 2010 18:24:23 +1300
Subject: [PATCH] assign texunits to samplers, instead of (wrongly) using
 unitid==textureid

---
 OpenRA.Renderer.Gl/Shader.cs  | 42 ++++++++++++++++++++++++++++-------
 OpenRA.Renderer.Gl/Texture.cs |  1 -
 2 files changed, 34 insertions(+), 9 deletions(-)

diff --git a/OpenRA.Renderer.Gl/Shader.cs b/OpenRA.Renderer.Gl/Shader.cs
index 59b2ecf2e5..abbcd566de 100644
--- a/OpenRA.Renderer.Gl/Shader.cs
+++ b/OpenRA.Renderer.Gl/Shader.cs
@@ -14,12 +14,15 @@ using OpenRA.FileFormats;
 using OpenRA.FileFormats.Graphics;
 using Tao.OpenGl;
 using System.Text;
+using System.Collections.Generic;
 
 namespace OpenRA.Renderer.Glsl
 {
 	public class Shader : IShader
 	{
 		int program;
+		readonly Dictionary<string, int> samplers = new Dictionary<string, int>();
+
 		public Shader(GraphicsDevice dev, string type)
 		{			
 			// Vertex shader
@@ -60,9 +63,30 @@ namespace OpenRA.Renderer.Glsl
             System.Text.StringBuilder log = new System.Text.StringBuilder(4024);
 			
 			Gl.glGetProgramInfoLog(program,4024,l,log);
-			Console.WriteLine(log.ToString());
-			
 			GraphicsDevice.CheckGlError();
+			Console.WriteLine(log.ToString());
+
+			int numAttribs;
+			Gl.glGetProgramiv( program, Gl.GL_ACTIVE_UNIFORMS, out numAttribs );
+			GraphicsDevice.CheckGlError();
+
+			Gl.glUseProgram(program);
+			GraphicsDevice.CheckGlError();
+
+			int nextTexUnit = 1;
+			for( int i = 0 ; i < numAttribs ; i++ )
+			{
+				int uLen, uSize, uType;
+				var sb = new StringBuilder(4096);
+				Gl.glGetActiveUniform( program, i, 4096, out uLen, out uSize, out uType, sb );
+				GraphicsDevice.CheckGlError();
+				if( uType == Gl.GL_SAMPLER_2D )
+				{
+					samplers.Add( sb.ToString(), nextTexUnit );
+					Gl.glUniform1i( i, nextTexUnit );
+					++nextTexUnit;
+				}
+			}
 		}
 
 		public void Render(Action a)
@@ -74,17 +98,19 @@ namespace OpenRA.Renderer.Glsl
 		}
 
 		public void SetValue(string name, ITexture t)
-		{			
+		{
+			if( t == null ) return;
 			Gl.glUseProgram(program);
 			GraphicsDevice.CheckGlError();
 			var texture = (Texture)t;
-			int param = Gl.glGetUniformLocation(program, name);
-			GraphicsDevice.CheckGlError();
-			
-			if (texture != null && param >= 0)
+			int texUnit;
+			if( samplers.TryGetValue( name, out texUnit ) )
 			{
-				Gl.glUniform1i(param, texture.texture);
+				Gl.glActiveTexture( Gl.GL_TEXTURE0 + texUnit );
 				GraphicsDevice.CheckGlError();
+				Gl.glBindTexture( Gl.GL_TEXTURE_2D, texture.texture );
+				GraphicsDevice.CheckGlError();
+				Gl.glActiveTexture( Gl.GL_TEXTURE0 );
 			}
 		}
 		
diff --git a/OpenRA.Renderer.Gl/Texture.cs b/OpenRA.Renderer.Gl/Texture.cs
index 47c430169c..6c6f1a517f 100644
--- a/OpenRA.Renderer.Gl/Texture.cs
+++ b/OpenRA.Renderer.Gl/Texture.cs
@@ -36,7 +36,6 @@ namespace OpenRA.Renderer.Glsl
 
 		void PrepareTexture()
 		{
-			Gl.glActiveTexture(Gl.GL_TEXTURE0 + texture);
 			GraphicsDevice.CheckGlError();
 			Gl.glBindTexture(Gl.GL_TEXTURE_2D, texture);
 			GraphicsDevice.CheckGlError();