for SH-3352: Create pixel shader to accumulate frame-to-frame absolute pixel differences

indra/newview/app_settings/shaders/class1/interface/twotexturecompareF.glsl

@@ -0,0 +1,42 @@
+/** 
+ * @file twotexturecompareF.glsl
+ *
+ * $LicenseInfo:firstyear=2007&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2007, Linden Research, Inc.
+ * 
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * 
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+
+#ifdef DEFINE_GL_FRAGCOLOR
+out vec4 frag_color;
+#else
+#define frag_color gl_FragColor
+#endif
+
+uniform sampler2D tex0;
+uniform sampler2D tex1;
+
+VARYING vec2 vary_texcoord0;
+VARYING vec2 vary_texcoord1;
+
+void main() 
+{
+	frag_color = texture2D(tex0, vary_texcoord0.xy) - texture2D(tex1, vary_texcoord0.xy);
+	frag_color[3] = 1.f;
+}

indra/newview/app_settings/shaders/class1/interface/twotexturecompareV.glsl

@@ -0,0 +1,41 @@
+/** 
+ * @file twotexturecompareV.glsl
+ *
+ * $LicenseInfo:firstyear=2007&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2007, Linden Research, Inc.
+ * 
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * 
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+ 
+uniform mat4 modelview_projection_matrix;
+
+ATTRIBUTE vec3 position;
+ATTRIBUTE vec2 texcoord0;
+ATTRIBUTE vec2 texcoord1;
+
+VARYING vec2 vary_texcoord0;
+VARYING vec2 vary_texcoord1;
+
+void main()
+{
+	gl_Position = modelview_projection_matrix * vec4(position.xyz, 1.0);
+	vary_texcoord0 = texcoord0;
+	vary_texcoord1 = texcoord1;
+}
+

indra/newview/llviewershadermgr.cpp

@@ -78,6 +78,7 @@ LLGLSLShader	gGlowCombineProgram;
 LLGLSLShader	gSplatTextureRectProgram;
 LLGLSLShader	gGlowCombineFXAAProgram;
 LLGLSLShader	gTwoTextureAddProgram;
+LLGLSLShader	gTwoTextureCompareProgram;
 LLGLSLShader	gOneTextureNoColorProgram;
 LLGLSLShader	gDebugProgram;
 LLGLSLShader	gClipProgram;
@@ -672,6 +673,7 @@ void LLViewerShaderMgr::unloadShaders()
 	gSplatTextureRectProgram.unload();
 	gGlowCombineFXAAProgram.unload();
 	gTwoTextureAddProgram.unload();
+	gTwoTextureCompareProgram.unload();
 	gOneTextureNoColorProgram.unload();
 	gSolidColorProgram.unload();
 
@@ -2706,6 +2708,22 @@ BOOL LLViewerShaderMgr::loadShadersInterface()
 		}
 	}
 
+	if (success)
+	{
+		gTwoTextureCompareProgram.mName = "Two Texture Compare Shader";
+		gTwoTextureCompareProgram.mShaderFiles.clear();
+		gTwoTextureCompareProgram.mShaderFiles.push_back(make_pair("interface/twotexturecompareV.glsl", GL_VERTEX_SHADER_ARB));
+		gTwoTextureCompareProgram.mShaderFiles.push_back(make_pair("interface/twotexturecompareF.glsl", GL_FRAGMENT_SHADER_ARB));
+		gTwoTextureCompareProgram.mShaderLevel = mVertexShaderLevel[SHADER_INTERFACE];
+		success = gTwoTextureCompareProgram.createShader(NULL, NULL);
+		if (success)
+		{
+			gTwoTextureCompareProgram.bind();
+			gTwoTextureCompareProgram.uniform1i("tex0", 0);
+			gTwoTextureCompareProgram.uniform1i("tex1", 1);
+		}
+	}
+
 	if (success)
 	{
 		gOneTextureNoColorProgram.mName = "One Texture No Color Shader";

indra/newview/llviewershadermgr.h

@@ -233,6 +233,8 @@ extern LLGLSLShader			gAlphaMaskProgram;
 
 //output tex0[tc0] + tex1[tc1]
 extern LLGLSLShader			gTwoTextureAddProgram;
+//output tex0[tc0] - tex1[tc1]
+extern LLGLSLShader			gTwoTextureCompareProgram;
 						
 extern LLGLSLShader			gOneTextureNoColorProgram;