feat: implement multi-layer texture binding

Minecraft.Client/Textures.cpp

@@ -428,7 +428,7 @@ void Textures::bindTextureLayers(ResourceLocation *resource)
 
 	for( int i = 0; i < layers; i++ )
 	{
-		RenderManager.TextureBind(loadTexture(resource->getTexture(i)));
+		RenderManager.TextureBind(i, loadTexture(resource->getTexture(i)));
 	}
 }
 
@@ -1520,3 +1520,4 @@ bool Textures::IsOriginalImage(TEXTURE_NAME texId, const wstring& name)
 	return false;
 }
 
+

Minecraft.Client/Windows64/4JLibs/inc/4J_Render.h

@@ -145,6 +145,7 @@ public:
 	int TextureCreate();
 	void TextureFree(int idx);
 	void TextureBind(int idx);
+	void TextureBind(int layer, int idx);
 	void TextureBindVertex(int idx);
 	void TextureSetTextureLevels(int levels);
 	int  TextureGetTextureLevels();
@@ -300,3 +301,4 @@ const int GL_TRIANGLE_STRIP = C4JRender::PRIMITIVE_TYPE_TRIANGLE_STRIP;
 extern C4JRender RenderManager;
 
 
+

Minecraft.Client/glWrapper.cpp

@@ -3,6 +3,17 @@
 #include "..\Minecraft.World\IntBuffer.h"
 #include "..\Minecraft.World\ByteBuffer.h"
 
+static int g_activeTextureLayer = 0;
+
+static int getTextureLayer(int textureUnit)
+{
+	if (textureUnit == GL_TEXTURE1)
+		return 1;
+	if (textureUnit >= GL_TEXTURE0)
+		return textureUnit - GL_TEXTURE0;
+	return 0;
+}
+
 void glViewport(int x, int y, int w, int h)
 {
 	// We don't really need anything here because minecraft doesn't current do anything other than the default viewport
@@ -139,7 +150,7 @@ void Display::swapBuffers()
 
 void glBindTexture(int target,int texture)
 {
-	RenderManager.TextureBind(texture);
+	RenderManager.TextureBind(g_activeTextureLayer, texture);
 }
 
 void glTexImage2D(int target,int level,int internalformat,int width,int height,int border,int format,int type, ByteBuffer *data)
@@ -190,7 +201,7 @@ void glDisable(int state)
 	switch(state)
 	{
 		case GL_TEXTURE_2D:
-			RenderManager.TextureBind(-1);
+			RenderManager.TextureBind(g_activeTextureLayer, -1);
 			break;
 		case GL_BLEND:
 			RenderManager.StateSetBlendEnable(false);
@@ -391,3 +402,22 @@ void glCullFace(int dir)
 {
 	RenderManager.StateSetFaceCullCW( dir == GL_BACK);
 }
+void glClientActiveTexture(int texture)
+{
+	glActiveTexture(texture);
+}
+
+void glActiveTexture(int texture)
+{
+	int layer = getTextureLayer(texture);
+	if (layer < 0)
+	{
+		layer = 0;
+	}
+	else if (layer > 3)
+	{
+		layer = 3;
+	}
+	g_activeTextureLayer = layer;
+}
+

Minecraft.Client/stubs.cpp

@@ -122,13 +122,6 @@ void glColorMaterial(int,int)
 }
 
 //1.8.2
-void glClientActiveTexture(int)
-{
-}
-
-void glActiveTexture(int)
-{
-}
 
 void glFlush()
 {