[GLES2] fix canvas_item sampler allocation

drivers/gles2/rasterizer_canvas_gles2.cpp

@@ -152,7 +152,7 @@ RasterizerStorageGLES2::Texture *RasterizerCanvasGLES2::_bind_canvas_texture(con
 			state.current_tex = RID();
 			state.current_tex_ptr = NULL;
 
-			glActiveTexture(GL_TEXTURE0);
+			glActiveTexture(GL_TEXTURE0 + storage->config.max_texture_image_units - 1);
 			glBindTexture(GL_TEXTURE_2D, storage->resources.white_tex);
 
 		} else {
@@ -167,7 +167,7 @@ RasterizerStorageGLES2::Texture *RasterizerCanvasGLES2::_bind_canvas_texture(con
 				texture->render_target->used_in_frame = true;
 			}
 
-			glActiveTexture(GL_TEXTURE0);
+			glActiveTexture(GL_TEXTURE0 + storage->config.max_texture_image_units - 1);
 			glBindTexture(GL_TEXTURE_2D, texture->tex_id);
 
 			state.current_tex = p_texture;
@@ -179,7 +179,7 @@ RasterizerStorageGLES2::Texture *RasterizerCanvasGLES2::_bind_canvas_texture(con
 		state.current_tex = RID();
 		state.current_tex_ptr = NULL;
 
-		glActiveTexture(GL_TEXTURE0);
+		glActiveTexture(GL_TEXTURE0 + storage->config.max_texture_image_units - 1);
 		glBindTexture(GL_TEXTURE_2D, storage->resources.white_tex);
 	}
 
@@ -889,7 +889,7 @@ void RasterizerCanvasGLES2::canvas_render_items(Item *p_item_list, int p_z, cons
 
 				for (int i = 0; i < tc; i++) {
 
-					glActiveTexture(GL_TEXTURE2 + i);
+					glActiveTexture(GL_TEXTURE0 + i);
 
 					RasterizerStorageGLES2::Texture *t = storage->texture_owner.getornull(textures[i].second);
 
@@ -1027,8 +1027,8 @@ void RasterizerCanvasGLES2::reset_canvas() {
 	// keeping this for now as there's nothing else that uses texture unit 2
 	// TODO ^
 	if (storage->frame.current_rt) {
-		glActiveTexture(GL_TEXTURE0 + 2);
-		glBindTexture(GL_TEXTURE_2D, storage->frame.current_rt->copy_screen_effect.color);
+		// glActiveTexture(GL_TEXTURE0 + 2);
+		// glBindTexture(GL_TEXTURE_2D, storage->frame.current_rt->copy_screen_effect.color);
 	}
 
 	glBindBuffer(GL_ARRAY_BUFFER, 0);

drivers/gles2/rasterizer_gles2.cpp

@@ -327,7 +327,7 @@ void RasterizerGLES2::set_boot_image(const Ref<Image> &p_image, const Color &p_c
 	screenrect.position += ((Size2(window_w, window_h) - screenrect.size) / 2.0).floor();
 
 	RasterizerStorageGLES2::Texture *t = storage->texture_owner.get(texture);
-	glActiveTexture(GL_TEXTURE0);
+	glActiveTexture(GL_TEXTURE0 + storage->config.max_texture_image_units - 1);
 	glBindTexture(GL_TEXTURE_2D, t->tex_id);
 	canvas->draw_generic_textured_rect(screenrect, Rect2(0, 0, 1, 1));
 	glBindTexture(GL_TEXTURE_2D, 0);
@@ -354,7 +354,7 @@ void RasterizerGLES2::blit_render_target_to_screen(RID p_render_target, const Re
 	canvas->canvas_begin();
 	glDisable(GL_BLEND);
 	glBindFramebuffer(GL_FRAMEBUFFER, RasterizerStorageGLES2::system_fbo);
-	glActiveTexture(GL_TEXTURE0);
+	glActiveTexture(GL_TEXTURE0 + storage->config.max_texture_image_units - 1);
 	glBindTexture(GL_TEXTURE_2D, rt->color);
 
 	// TODO normals

drivers/gles2/rasterizer_storage_gles2.cpp

@@ -1303,6 +1303,10 @@ void RasterizerStorageGLES2::shader_get_param_list(RID p_shader, List<PropertyIn
 				pi.hint = PROPERTY_HINT_RESOURCE_TYPE;
 				pi.hint_string = "CubeMap";
 			} break;
+
+			default: {
+
+			} break;
 		}
 
 		p_param_list->push_back(pi);

drivers/gles2/shader_gles2.cpp

@@ -967,19 +967,7 @@ void ShaderGLES2::use_material(void *p_material) {
 					value.second.write[15].real = 1;
 				} break;
 
-				case ShaderLanguage::TYPE_SAMPLER2D: {
-
-				} break;
-
-				case ShaderLanguage::TYPE_ISAMPLER2D: {
-
-				} break;
-
-				case ShaderLanguage::TYPE_USAMPLER2D: {
-
-				} break;
-
-				case ShaderLanguage::TYPE_SAMPLERCUBE: {
+				default: {
 
 				} break;
 			}

drivers/gles2/shaders/canvas.glsl

@@ -96,9 +96,9 @@ precision mediump float;
 precision mediump int;
 #endif
 
-uniform sampler2D color_texture; // texunit:0
+uniform sampler2D color_texture; // texunit:-1
 uniform highp vec2 color_texpixel_size;
-uniform mediump sampler2D normal_texture; // texunit:1
+uniform mediump sampler2D normal_texture; // texunit:-2
 
 varying mediump vec2 uv_interp;
 varying mediump vec4 color_interp;
@@ -109,7 +109,7 @@ uniform vec4 final_modulate;
 
 #ifdef SCREEN_TEXTURE_USED
 
-uniform sampler2D screen_texture; // texunit:2
+uniform sampler2D screen_texture; // texunit:-3
 
 #endif