Index: ps/trunk/binaries/data/mods/mod/shaders/effects/canvas2d.xml
===================================================================
--- ps/trunk/binaries/data/mods/mod/shaders/effects/canvas2d.xml	(revision 26215)
+++ ps/trunk/binaries/data/mods/mod/shaders/effects/canvas2d.xml	(revision 26216)
@@ -1,14 +1,18 @@
 <?xml version="1.0" encoding="utf-8"?>
 <effect>
 
-    <technique>
-        <require shaders="arb"/>
-        <pass shader="arb/canvas2d"/>
-    </technique>
+	<technique>
+		<require shaders="arb"/>
+		<pass shader="arb/canvas2d">
+			<blend src="src_alpha" dst="one_minus_src_alpha"/>
+		</pass>
+	</technique>
 
-    <technique>
-        <require shaders="glsl"/>
-        <pass shader="glsl/canvas2d"/>
-    </technique>
+	<technique>
+		<require shaders="glsl"/>
+		<pass shader="glsl/canvas2d">
+			<blend src="src_alpha" dst="one_minus_src_alpha"/>
+		</pass>
+	</technique>
 
 </effect>
Index: ps/trunk/source/graphics/Canvas2D.cpp
===================================================================
--- ps/trunk/source/graphics/Canvas2D.cpp	(revision 26215)
+++ ps/trunk/source/graphics/Canvas2D.cpp	(revision 26216)
@@ -1,200 +1,195 @@
 /* Copyright (C) 2022 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation, either version 2 of the License, or
  * (at your option) any later version.
  *
  * 0 A.D. 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 General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 #include "precompiled.h"
 
 #include "Canvas2D.h"
 
 #include "graphics/Color.h"
 #include "graphics/ShaderManager.h"
 #include "graphics/TextRenderer.h"
 #include "graphics/TextureManager.h"
 #include "gui/GUIMatrix.h"
 #include "maths/Rect.h"
 #include "maths/Vector2D.h"
 #include "ps/CStrInternStatic.h"
 #include "renderer/Renderer.h"
 
 #include <array>
 
 namespace
 {
 
 // Array of 2D elements unrolled into 1D array.
 using PlaneArray2D = std::array<float, 8>;
 
 inline void DrawTextureImpl(const CShaderProgramPtr& shader, CTexturePtr texture,
 	const PlaneArray2D& vertices, PlaneArray2D uvs,
 	const CColor& multiply, const CColor& add, const float grayscaleFactor)
 {
 	shader->BindTexture(str_tex, texture);
 	for (size_t idx = 0; idx < uvs.size(); idx += 2)
 	{
 		if (texture->GetWidth() > 0.0f)
 			uvs[idx + 0] /= texture->GetWidth();
 		if (texture->GetHeight() > 0.0f)
 			uvs[idx + 1] /= texture->GetHeight();
 	}
 
 	shader->Uniform(str_transform, GetDefaultGuiMatrix());
 	shader->Uniform(str_colorAdd, add);
 	shader->Uniform(str_colorMul, multiply);
 	shader->Uniform(str_grayscaleFactor, grayscaleFactor);
 	shader->VertexPointer(2, GL_FLOAT, 0, vertices.data());
 	shader->TexCoordPointer(GL_TEXTURE0, 2, GL_FLOAT, 0, uvs.data());
 	shader->AssertPointersBound();
 
 	glDrawArrays(GL_TRIANGLE_FAN, 0, vertices.size() / 2);
 }
 
 } // anonymous namespace
 
 class CCanvas2D::Impl
 {
 public:
 	void BindTechIfNeeded()
 	{
 		if (Tech)
 			return;
 
-		glEnable(GL_BLEND);
-		glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
-
 		CShaderDefines defines;
 		Tech = g_Renderer.GetShaderManager().LoadEffect(str_canvas2d, defines);
 		ENSURE(Tech);
 		Tech->BeginPass();
 	}
 
 	void UnbindTech()
 	{
 		if (!Tech)
 			return;
 
 		Tech->EndPass();
 		Tech.reset();
-
-		glDisable(GL_BLEND);
 	}
 
 	CShaderTechniquePtr Tech;
 };
 
 CCanvas2D::CCanvas2D() : m(std::make_unique<Impl>())
 {
 
 }
 
 CCanvas2D::~CCanvas2D()
 {
 	Flush();
 }
 
 void CCanvas2D::DrawLine(const std::vector<CVector2D>& points, const float width, const CColor& color)
 {
 	m->BindTechIfNeeded();
 
 	std::vector<float> vertices;
 	std::vector<float> uvs(points.size() * 2, 0.0f);
 	vertices.reserve(points.size() * 2);
 	for (const CVector2D& point : points)
 	{
 		vertices.emplace_back(point.X);
 		vertices.emplace_back(point.Y);
 	}
 
 	CShaderProgramPtr shader = m->Tech->GetShader();
 	shader->BindTexture(str_tex, g_Renderer.GetTextureManager().GetTransparentTexture());
 	shader->Uniform(str_transform, GetDefaultGuiMatrix());
 	shader->Uniform(str_colorAdd, color);
 	shader->Uniform(str_colorMul, CColor(0.0f, 0.0f, 0.0f, 0.0f));
 	shader->Uniform(str_grayscaleFactor, 0.0f);
 	shader->VertexPointer(2, GL_FLOAT, 0, vertices.data());
 	shader->TexCoordPointer(GL_TEXTURE0, 2, GL_FLOAT, 0, uvs.data());
 	shader->AssertPointersBound();
 
 #if !CONFIG2_GLES
 	glEnable(GL_LINE_SMOOTH);
 #endif
 	glLineWidth(width);
 	glDrawArrays(GL_LINE_STRIP, 0, vertices.size() / 2);
 	glLineWidth(1.0f);
 #if !CONFIG2_GLES
 	glDisable(GL_LINE_SMOOTH);
 #endif
 }
 
 void CCanvas2D::DrawRect(const CRect& rect, const CColor& color)
 {
 	const PlaneArray2D uvs = {
 		0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f
 	};
 	const PlaneArray2D vertices = {
 		rect.left, rect.bottom,
 		rect.right, rect.bottom,
 		rect.right, rect.top,
 		rect.left, rect.top
 	};
 
 	m->BindTechIfNeeded();
 	DrawTextureImpl(
 		m->Tech->GetShader(), g_Renderer.GetTextureManager().GetTransparentTexture(),
 		vertices, uvs, CColor(0.0f, 0.0f, 0.0f, 0.0f), color, 0.0f);
 }
 
 void CCanvas2D::DrawTexture(CTexturePtr texture, const CRect& destination)
 {
 	DrawTexture(texture,
 		destination, CRect(0, 0, texture->GetWidth(), texture->GetHeight()),
 		CColor(1.0f, 1.0f, 1.0f, 1.0f), CColor(0.0f, 0.0f, 0.0f, 0.0f), 0.0f);
 }
 
 void CCanvas2D::DrawTexture(
 	CTexturePtr texture, const CRect& destination, const CRect& source,
 	const CColor& multiply, const CColor& add, const float grayscaleFactor)
 {
 	const PlaneArray2D uvs = {
 		source.left, source.bottom,
 		source.right, source.bottom,
 		source.right, source.top,
 		source.left, source.top
 	};
 	const PlaneArray2D vertices = {
 		destination.left, destination.bottom,
 		destination.right, destination.bottom,
 		destination.right, destination.top,
 		destination.left, destination.top
 	};
 
 	m->BindTechIfNeeded();
 	DrawTextureImpl(m->Tech->GetShader(), texture, vertices, uvs, multiply, add, grayscaleFactor);
 }
 
 void CCanvas2D::DrawText(CTextRenderer& textRenderer)
 {
 	m->BindTechIfNeeded();
 
 	CShaderProgramPtr shader = m->Tech->GetShader();
 	shader->Uniform(str_grayscaleFactor, 0.0f);
 
 	textRenderer.Render(shader, GetDefaultGuiMatrix());
 }
 
 void CCanvas2D::Flush()
 {
 	m->UnbindTech();
 }