Improve performance of Shader:send when the Shader is not active.

It now defers uploading the uniforms to the program object until the shader becomes active again, instead of activating the shader program and deactivating it each time Shader:send is called.

--HG--
branch : minor

src/modules/graphics/opengl/Shader.cpp

@@ -548,13 +548,19 @@ void Shader::attach(bool temporary)
 
 		if (!temporary)
 		{
-			// make sure all sent textures are properly bound to their respective texture units
-			// note: list potentially contains texture ids of deleted/invalid textures!
+			// Make sure all textures are properly bound to their respective
+			// texture units.
 			for (int i = 1; i < (int) textureUnits.size(); ++i)
 			{
 				if (textureUnits[i].active)
 					gl.bindTextureToUnit(textureUnits[i].texture, i, false);
 			}
+
+			// send any pending uniforms to the shader program.
+			for (const auto &p : pendingUniformUpdates)
+				updateUniform(p.first, p.second);
+
+			pendingUniformUpdates.clear();
 		}
 	}
 }
@@ -587,11 +593,15 @@ const Shader::UniformInfo *Shader::getUniformInfo(const std::string &name) const
 
 void Shader::updateUniform(const UniformInfo *info, int count, bool internalUpdate)
 {
+	if (current != this)
+	{
+		pendingUniformUpdates.push_back(std::make_pair(info, count));
+		return;
+	}
+
 	if (!internalUpdate)
 		flushStreamDraws();
 
-	TemporaryAttacher attacher(this, !internalUpdate);
-
 	int location = info->location;
 	UniformType type = info->baseType;
 
@@ -682,7 +692,9 @@ void Shader::sendTextures(const UniformInfo *info, Texture **textures, int count
 	if (info->baseType != UNIFORM_SAMPLER)
 		return;
 
-	if (!internalUpdate)
+	bool shaderactive = current == this;
+
+	if (!internalUpdate && shaderactive)
 		flushStreamDraws();
 
 	count = std::min(count, info->count);
@@ -721,14 +733,17 @@ void Shader::sendTextures(const UniformInfo *info, Texture **textures, int count
 		{
 			GLuint gltex = (GLuint) textures[i]->getHandle();
 
-			gl.bindTextureToUnit(gltex, texunit, false);
+			if (shaderactive)
+				gl.bindTextureToUnit(gltex, texunit, false);
 
-			// store texture id so it can be re-bound to the proper texture unit later
+			// Store texture id so it can be re-bound to the texture unit later.
 			textureUnits[texunit].texture = gltex;
 		}
 		else
 		{
-			gl.bindTextureToUnit((GLuint) 0, texunit, false);
+			if (shaderactive)
+				gl.bindTextureToUnit((GLuint) 0, texunit, false);
+
 			textureUnits[texunit].texture = 0;
 			textureUnits[texunit].active = false;
 		}
@@ -812,7 +827,8 @@ void Shader::setVideoTextures(GLuint ytexture, GLuint cbtexture, GLuint crtextur
 		{
 			// Store texture id so it can be re-bound later.
 			textureUnits[videoTextureUnits[i]].texture = textures[i];
-			gl.bindTextureToUnit(textures[i], videoTextureUnits[i], false);
+			if (current == this)
+				gl.bindTextureToUnit(textures[i], videoTextureUnits[i], false);
 		}
 	}
 }
@@ -824,7 +840,7 @@ void Shader::checkSetScreenParams()
 	auto gfx = Module::getInstance<Graphics>(Module::M_GRAPHICS);
 	bool canvasActive = gfx->isCanvasActive();
 
-	if (view == lastViewport && canvasWasActive == canvasActive)
+	if ((view == lastViewport && canvasWasActive == canvasActive) || current != this)
 		return;
 
 	// In the shader, we do pixcoord.y = gl_FragCoord.y * params.z + params.w.
@@ -850,12 +866,8 @@ void Shader::checkSetScreenParams()
 	}
 
 	GLint location = builtinUniforms[BUILTIN_SCREEN_SIZE];
-
 	if (location >= 0)
-	{
-		TemporaryAttacher attacher(this, true);
 		glUniform4fv(location, 1, params);
-	}
 
 	canvasWasActive = canvasActive;
 	lastViewport = view;
@@ -863,22 +875,21 @@ void Shader::checkSetScreenParams()
 
 void Shader::checkSetPointSize(float size)
 {
-	if (size == lastPointSize)
+	if (size == lastPointSize || current != this)
 		return;
 
 	GLint location = builtinUniforms[BUILTIN_POINT_SIZE];
-
 	if (location >= 0)
-	{
-		TemporaryAttacher attacher(this, true);
 		glUniform1f(location, size);
-	}
 
 	lastPointSize = size;
 }
 
 void Shader::checkSetBuiltinUniforms()
 {
+	if (current != this)
+		return;
+
 	checkSetScreenParams();
 
 	// We use a more efficient method for sending transformation matrices to
@@ -888,10 +899,9 @@ void Shader::checkSetBuiltinUniforms()
 		checkSetPointSize(gl.getPointSize());
 
 		auto gfx = Module::getInstance<graphics::Graphics>(Module::M_GRAPHICS);
-		const Matrix4 &curproj = gfx->getProjection();
 
+		const Matrix4 &curproj = gfx->getProjection();
 		const Matrix4 &curxform = gfx->getTransform();
-		TemporaryAttacher attacher(this, true);
 
 		bool tpmatrixneedsupdate = false;
 

src/modules/graphics/opengl/Shader.h

@@ -243,6 +243,8 @@ private:
 	// Texture unit pool for setting images
 	std::vector<TextureUnit> textureUnits;
 
+	std::vector<std::pair<const UniformInfo *, int>> pendingUniformUpdates;
+
 	bool canvasWasActive;
 	Rect lastViewport;