diff --git a/libweston/renderer-gl/gl-renderer-internal.h b/libweston/renderer-gl/gl-renderer-internal.h
index 495b99cad..330355fa4 100644
--- a/libweston/renderer-gl/gl-renderer-internal.h
+++ b/libweston/renderer-gl/gl-renderer-internal.h
@@ -26,6 +26,15 @@
  * SOFTWARE.
  */
 
+/*
+ * GL renderer best practices:
+ *
+ * 1. Texture units
+ *    1. Fixed allocation using the gl_tex_unit enumeration.
+ *    2. Any functions changing the active unit must restore it to 0 before
+ *       return so that other functions can assume a default value.
+ */
+
 #ifndef GL_RENDERER_INTERNAL_H
 #define GL_RENDERER_INTERNAL_H
 
diff --git a/libweston/renderer-gl/gl-renderer.c b/libweston/renderer-gl/gl-renderer.c
index 34f83360f..c6f9262a2 100644
--- a/libweston/renderer-gl/gl-renderer.c
+++ b/libweston/renderer-gl/gl-renderer.c
@@ -574,7 +574,6 @@ gl_fbo_texture_init(struct gl_fbo_texture *fbotex,
 	GLuint shadow_fbo;
 	GLuint shadow_tex;
 
-	glActiveTexture(GL_TEXTURE0);
 	glGenTextures(1, &shadow_tex);
 	glBindTexture(GL_TEXTURE_2D, shadow_tex);
 	glTexImage2D(GL_TEXTURE_2D, 0, internal_format, width, height, 0,
@@ -1834,6 +1833,8 @@ update_wireframe_tex(struct gl_renderer *gr,
 		glTexImage2D(GL_TEXTURE_2D, i, GL_LUMINANCE, new_size, 1, 0,
 			     GL_LUMINANCE, GL_UNSIGNED_BYTE, buffer);
 	free(buffer);
+
+	glActiveTexture(GL_TEXTURE0);
 }
 
 static void
@@ -1986,7 +1987,6 @@ draw_output_borders(struct weston_output *output,
 	weston_matrix_scale(&sconf.projection,
 			    2.0 / fb->width, go->y_flip * 2.0 / fb->height, 1);
 
-	glActiveTexture(GL_TEXTURE0);
 	glEnableVertexAttribArray(SHADER_ATTRIB_LOC_POSITION);
 	glEnableVertexAttribArray(SHADER_ATTRIB_LOC_TEXCOORD);
 
@@ -2547,8 +2547,6 @@ gl_renderer_flush_damage(struct weston_paint_node *pnode)
 
 	data = wl_shm_buffer_get_data(buffer->shm_buffer);
 
-	glActiveTexture(GL_TEXTURE0);
-
 	if (gb->needs_full_upload || quirks->gl_force_full_upload) {
 		wl_shm_buffer_begin_access(buffer->shm_buffer);
 
@@ -2650,8 +2648,6 @@ ensure_textures(struct gl_buffer_state *gb, GLenum target, int num_textures)
 
 	assert(gb->num_textures == 0);
 
-	glActiveTexture(GL_TEXTURE0);
-
 	for (i = 0; i < num_textures; i++) {
 		glGenTextures(1, &gb->textures[i]);
 		glBindTexture(target, gb->textures[i]);
@@ -3458,6 +3454,7 @@ gl_renderer_attach_buffer(struct weston_surface *surface,
 		glBindTexture(target, gb->textures[i]);
 		gr->image_target_texture_2d(target, gb->images[i]);
 	}
+	glActiveTexture(GL_TEXTURE0);
 }
 
 static const struct weston_drm_format_array *
@@ -3710,7 +3707,6 @@ gl_renderer_surface_copy_content(struct weston_surface *surface,
 
 	gl_shader_config_set_input_textures(&sconf, gs);
 
-	glActiveTexture(GL_TEXTURE0);
 	glGenTextures(1, &tex);
 	glBindTexture(GL_TEXTURE_2D, tex);
 	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, cw, ch,
diff --git a/libweston/renderer-gl/gl-shader-config-color-transformation.c b/libweston/renderer-gl/gl-shader-config-color-transformation.c
index 127a0f5af..244276f62 100644
--- a/libweston/renderer-gl/gl-shader-config-color-transformation.c
+++ b/libweston/renderer-gl/gl-shader-config-color-transformation.c
@@ -201,7 +201,6 @@ gl_color_curve_lut_3x1d(struct gl_renderer *gr,
 
 	curve->u.lut_3x1d.fill_in(xform, lut, lut_len);
 
-	glActiveTexture(GL_TEXTURE0);
 	glGenTextures(1, &tex);
 	glBindTexture(GL_TEXTURE_2D, tex);
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
@@ -238,7 +237,6 @@ gl_3d_lut(struct gl_renderer *gr,
 
 	xform->mapping.u.lut3d.fill_in(xform, lut, dim_size);
 
-	glActiveTexture(GL_TEXTURE0);
 	glGenTextures(1, &tex3d);
 	glBindTexture(GL_TEXTURE_3D, tex3d);
 	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
diff --git a/libweston/renderer-gl/gl-shaders.c b/libweston/renderer-gl/gl-shaders.c
index b49b4eaa1..007e107e7 100644
--- a/libweston/renderer-gl/gl-shaders.c
+++ b/libweston/renderer-gl/gl-shaders.c
@@ -767,6 +767,8 @@ gl_shader_load_config(struct gl_shader *shader,
 
 	if (sconf->req.wireframe)
 		glUniform1i(shader->tex_uniform_wireframe, TEX_UNIT_WIREFRAME);
+
+	glActiveTexture(GL_TEXTURE0);
 }
 
 bool