diff --git a/src/modules/graphics/Shader.cpp b/src/modules/graphics/Shader.cpp
index d4751f475..ed67ef263 100644
--- a/src/modules/graphics/Shader.cpp
+++ b/src/modules/graphics/Shader.cpp
@@ -174,12 +174,24 @@ void Shader::attachDefault()
 	current = nullptr;
 }
 
+TextureType Shader::getMainTextureType() const
+{
+	const UniformInfo *info = getUniformInfo(BUILTIN_TEXTURE_MAIN);
+	return info != nullptr ? info->textureType : TEXTURE_MAX_ENUM;
+}
+
 void Shader::checkMainTextureType(TextureType textype) const
 {
 	const UniformInfo *info = getUniformInfo(BUILTIN_TEXTURE_MAIN);
 
 	if (info != nullptr && info->textureType != TEXTURE_MAX_ENUM && info->textureType != textype)
-		throw love::Exception("Texture's type must match the type of the shader's main texture.");
+	{
+		const char *textypestr = "unknown";
+		const char *shadertextypestr = "unknown";
+		Texture::getConstant(textype, textypestr);
+		Texture::getConstant(info->textureType, shadertextypestr);
+		throw love::Exception("Texture's type (%s) must match the type of the shader's main texture type (%s).", textypestr, shadertextypestr);
+	}
 }
 
 bool Shader::validate(Graphics *gfx, bool gles, const ShaderSource &source, bool checkWithDefaults, std::string &err)
diff --git a/src/modules/graphics/Shader.h b/src/modules/graphics/Shader.h
index 1589ec5ff..37905eeae 100644
--- a/src/modules/graphics/Shader.h
+++ b/src/modules/graphics/Shader.h
@@ -176,6 +176,7 @@ public:
 	 **/
 	virtual void setVideoTextures(Texture *ytexture, Texture *cbtexture, Texture *crtexture) = 0;
 
+	TextureType getMainTextureType() const;
 	void checkMainTextureType(TextureType textype) const;
 
 	virtual ptrdiff_t getHandle() const = 0;
diff --git a/src/modules/graphics/opengl/Mesh.cpp b/src/modules/graphics/opengl/Mesh.cpp
index 76fc2eb75..9173ebdcd 100644
--- a/src/modules/graphics/opengl/Mesh.cpp
+++ b/src/modules/graphics/opengl/Mesh.cpp
@@ -134,10 +134,7 @@ void Mesh::drawInstanced(love::graphics::Graphics *gfx, const love::Matrix4 &m,
 
 	gl.useVertexAttribArrays(enabledattribs, instancedattribs);
 
-	if (texture.get())
-		gl.bindTextureToUnit(texture, 0, false);
-	else
-		gl.bindTextureToUnit(TEXTURE_2D, gl.getDefaultTexture(TEXTURE_2D), 0, false);
+	gl.bindTextureToUnit(texture, 0, false);
 
 	Graphics::TempTransform transform(gfx, m);
 
diff --git a/src/modules/graphics/opengl/OpenGL.cpp b/src/modules/graphics/opengl/OpenGL.cpp
index 26bc61a2d..553ede222 100644
--- a/src/modules/graphics/opengl/OpenGL.cpp
+++ b/src/modules/graphics/opengl/OpenGL.cpp
@@ -867,8 +867,25 @@ void OpenGL::bindTextureToUnit(TextureType target, GLuint texture, int textureun
 
 void OpenGL::bindTextureToUnit(Texture *texture, int textureunit, bool restoreprev)
 {
-	GLuint handle = texture != nullptr ? (GLuint) texture->getHandle() : getDefaultTexture(TEXTURE_2D);
-	TextureType textype = texture != nullptr ? texture->getTextureType() : TEXTURE_2D;
+	TextureType textype = TEXTURE_2D;
+	GLuint handle = 0;
+
+	if (texture != nullptr)
+	{
+		textype = texture->getTextureType();
+		handle = (GLuint) texture->getHandle();
+	}
+	else
+	{
+		if (textureunit == 0 && Shader::current != nullptr)
+		{
+			TextureType shadertex = Shader::current->getMainTextureType();
+			if (shadertex != TEXTURE_MAX_ENUM)
+				textype = shadertex;
+		}
+
+		handle = getDefaultTexture(textype);
+	}
 
 	bindTextureToUnit(textype, handle, textureunit, restoreprev);
 }
diff --git a/src/modules/graphics/wrap_Graphics.lua b/src/modules/graphics/wrap_Graphics.lua
index b42408960..fb2594ddf 100644
--- a/src/modules/graphics/wrap_Graphics.lua
+++ b/src/modules/graphics/wrap_Graphics.lua
@@ -262,15 +262,11 @@ void main() {
 	love_PixelColor = effect(VaryingColor, MainTex, VaryingTexCoord.st, love_PixelCoord);
 }]],
 
-	MAIN_MULTI_CANVAS = [[
-uniform sampler2D MainTex;
-varying mediump vec4 VaryingTexCoord;
-varying mediump vec4 VaryingColor;
-
-void effects(vec4 vcolor, Image tex, vec2 texcoord, vec2 pixcoord);
+	MAIN_CUSTOM = [[
+void effect();
 
 void main() {
-	effects(VaryingColor, MainTex, VaryingTexCoord.st, love_PixelCoord);
+	effect();
 }]],
 }
 
@@ -279,7 +275,7 @@ local function getLanguageTarget(code)
 	return (code:match("^%s*#pragma language (%w+)")) or "glsl1"
 end
 
-local function createShaderStageCode(stage, code, lang, gles, glsl1on3, gammacorrect, multicanvas)
+local function createShaderStageCode(stage, code, lang, gles, glsl1on3, gammacorrect, custom)
 	stage = stage:upper()
 	local lines = {
 		GLSL.VERSION[lang][gles],
@@ -291,7 +287,7 @@ local function createShaderStageCode(stage, code, lang, gles, glsl1on3, gammacor
 		GLSL.UNIFORMS,
 		GLSL.FUNCTIONS,
 		GLSL[stage].FUNCTIONS,
-		multicanvas and GLSL[stage].MAIN_MULTI_CANVAS or GLSL[stage].MAIN,
+		custom and GLSL[stage].MAIN_CUSTOM or GLSL[stage].MAIN,
 		(lang == "glsl3" or gles) and "#line 1" or "#line 0",
 		code,
 	}
@@ -305,8 +301,8 @@ end
 local function isPixelCode(code)
 	if code:match("vec4%s+effect%s*%(") then
 		return true
-	elseif code:match("void%s+effects%s*%(") then
-		-- function for rendering to multiple canvases simultaneously
+	elseif code:match("void%s+effect%s*%(") then
+		-- custom effect function
 		return true, true
 	else
 		return false
@@ -315,17 +311,17 @@ end
 
 function love.graphics._shaderCodeToGLSL(gles, arg1, arg2)
 	local vertexcode, pixelcode
-	local is_multicanvas = false -- whether pixel code has "effects" function instead of "effect"
+	local is_custompixel = false -- whether pixel code has "effects" function instead of "effect"
 
 	if arg1 then
 		if isVertexCode(arg1) then
 			vertexcode = arg1 -- first arg contains vertex shader code
 		end
 
-		local ispixel, isMultiCanvas = isPixelCode(arg1)
+		local ispixel, isCustomPixel = isPixelCode(arg1)
 		if ispixel then
 			pixelcode = arg1 -- first arg contains pixel shader code
-			is_multicanvas = isMultiCanvas
+			is_custompixel = isCustomPixel
 		end
 	end
 	
@@ -334,10 +330,10 @@ function love.graphics._shaderCodeToGLSL(gles, arg1, arg2)
 			vertexcode = arg2 -- second arg contains vertex shader code
 		end
 
-		local ispixel, isMultiCanvas = isPixelCode(arg2)
+		local ispixel, isCustomPixel = isPixelCode(arg2)
 		if ispixel then
 			pixelcode = arg2 -- second arg contains pixel shader code
-			is_multicanvas = isMultiCanvas
+			is_custompixel = isCustomPixel
 		end
 	end
 
@@ -368,7 +364,7 @@ function love.graphics._shaderCodeToGLSL(gles, arg1, arg2)
 		vertexcode = createShaderStageCode("VERTEX", vertexcode, lang, gles, glsl1on3, gammacorrect)
 	end
 	if pixelcode then
-		pixelcode = createShaderStageCode("PIXEL", pixelcode, lang, gles, glsl1on3, gammacorrect, is_multicanvas)
+		pixelcode = createShaderStageCode("PIXEL", pixelcode, lang, gles, glsl1on3, gammacorrect, is_custompixel)
 	end
 
 	return vertexcode, pixelcode