Texel (texture2D) calls in shaders now return pure white instead of pure black when drawing untextured graphics primitives. This prevents the need for separate "passthrough" shaders to be used when drawing graphics primitives vs images.

src/modules/graphics/opengl/OpenGL.cpp

@@ -89,6 +89,24 @@ void initializeContext()
 
 		glGetIntegerv(GL_TEXTURE_BINDING_2D, (GLint *) &textureUnits[0]);
 	}
+
+	// Set the 'default' texture (id 0) as a repeating white pixel.
+	// Otherwise, texture2D inside a shader would return black when drawing graphics primitives,
+	// which would create the need to use different "passthrough" shaders for untextured primitives vs images.
+
+	GLuint curtexture = textureUnits[curTextureUnit];
+	bindTexture(0);
+
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+
+	GLubyte pixel = 255;
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE8, 1, 1, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, &pixel);
+
+	bindTexture(curtexture);
 }
 
 void uninitializeContext()