Revert "Batch GLES2 draw calls"

This reverts commit f55039b194.

The GLES2 batching seems to require more testing and tweaking in order
to actually make the performance better on Android devices. It's been
proved with #21184 that the current implementation has it's drawbacks
therefore I suggest reverting the commit for now.

drivers/gles2/rasterizer_canvas_gles2.h

@@ -50,44 +50,23 @@ public:
 		Color final_modulate;
 
 		float time;
-
-		Size2 texpixel_size;
-	};
-
-	struct Vertex {
-		Vector2 v;
-		Color c;
-		Vector2 uv;
 	};
 
 	struct Data {
 
-		GLuint vertex_buffer;
-		GLuint index_buffer;
+		GLuint canvas_quad_vertices;
+		GLuint polygon_buffer;
+		GLuint polygon_index_buffer;
 
-		uint32_t vertex_buffer_size;
-		uint32_t index_buffer_size;
+		uint32_t polygon_buffer_size;
 
-		int ninepatch_elements[3 * 2 * 9];
+		GLuint ninepatch_vertices;
+		GLuint ninepatch_elements;
 
-		int *mem_index_buffer;
-		uint32_t mem_index_buffer_offset;
-		uint32_t mem_index_buffer_size;
-
-		Vertex *mem_vertex_buffer;
-		uint32_t mem_vertex_buffer_offset;
-		uint32_t mem_vertex_buffer_size;
-
-		GLuint primitive;
-		GLuint texture;
 	} data;
 
 	struct State {
 		Uniforms uniforms;
-		Uniforms prev_uniforms;
-
-		bool tiled;
-
 		bool canvas_texscreen_used;
 		CanvasShaderGLES2 canvas_shader;
 		// CanvasShadowShaderGLES3 canvas_shadow_shader;
@@ -120,16 +99,9 @@ public:
 
 	_FORCE_INLINE_ void _set_texture_rect_mode(bool p_enable, bool p_ninepatch = false);
 
+	_FORCE_INLINE_ void _draw_gui_primitive(int p_points, const Vector2 *p_vertices, const Color *p_colors, const Vector2 *p_uvs);
 	_FORCE_INLINE_ void _draw_polygon(const int *p_indices, int p_index_count, int p_vertex_count, const Vector2 *p_vertices, const Vector2 *p_uvs, const Color *p_colors, bool p_singlecolor);
-
-	_FORCE_INLINE_ void _begin(const GLuint p_primitive);
-	_FORCE_INLINE_ void _prepare(const int p_vertex_count, const int p_index_count);
-	_FORCE_INLINE_ void _commit(const int p_vertex_count, const int p_index_count);
-
-	_FORCE_INLINE_ void _flush();
-	_FORCE_INLINE_ void _draw(const GLuint p_primitive, const int p_vertex_count, const Vertex *p_vertices, const int p_index_count, const int *p_indices);
-
-	_FORCE_INLINE_ void _untile();
+	_FORCE_INLINE_ void _draw_generic(GLuint p_primitive, int p_vertex_count, const Vector2 *p_vertices, const Vector2 *p_uvs, const Color *p_colors, bool p_singlecolor);
 
 	_FORCE_INLINE_ void _canvas_item_render_commands(Item *p_item, Item *current_clip, bool &reclip, RasterizerStorageGLES2::Material *p_material);
 	_FORCE_INLINE_ void _copy_texscreen(const Rect2 &p_rect);
@@ -142,8 +114,8 @@ public:
 	virtual void reset_canvas();
 
 	RasterizerStorageGLES2::Texture *_bind_canvas_texture(const RID &p_texture, const RID &p_normal_map);
-	_FORCE_INLINE_ void _bind_shader(RasterizerStorageGLES2::Material *p_material);
 
+	void _bind_quad_buffer();
 	void draw_generic_textured_rect(const Rect2 &p_rect, const Rect2 &p_src);
 
 	void initialize();

drivers/gles2/rasterizer_gles2.cpp

@@ -345,6 +345,9 @@ void RasterizerGLES2::blit_render_target_to_screen(RID p_render_target, const Re
 	RasterizerStorageGLES2::RenderTarget *rt = storage->render_target_owner.getornull(p_render_target);
 	ERR_FAIL_COND(!rt);
 
+	canvas->state.canvas_shader.set_conditional(CanvasShaderGLES2::USE_TEXTURE_RECT, true);
+	canvas->state.canvas_shader.set_conditional(CanvasShaderGLES2::USE_UV_ATTRIBUTE, false);
+
 	canvas->state.canvas_shader.set_custom_shader(0);
 	canvas->state.canvas_shader.bind();
 
@@ -356,7 +359,7 @@ void RasterizerGLES2::blit_render_target_to_screen(RID p_render_target, const Re
 
 	// TODO normals
 
-	canvas->draw_generic_textured_rect(p_screen_rect, Rect2(0, 1, 1, -1));
+	canvas->draw_generic_textured_rect(p_screen_rect, Rect2(0, 0, 1, -1));
 
 	glBindTexture(GL_TEXTURE_2D, 0);
 	canvas->canvas_end();

drivers/gles2/rasterizer_storage_gles2.h

@@ -252,7 +252,7 @@ public:
 		int mipmaps;
 
 		bool active;
-		GLuint tex_id;
+		GLenum tex_id;
 
 		uint16_t stored_cube_sides;
 
@@ -429,8 +429,6 @@ public:
 			bool uses_screen_texture;
 			bool uses_screen_uv;
 			bool uses_time;
-			bool uses_modelview_matrix;
-			bool uses_vertex;
 
 		} canvas_item;
 

drivers/gles2/shader_gles2.cpp

@@ -122,11 +122,13 @@ GLint ShaderGLES2::get_uniform_location(int p_index) const {
 }
 
 bool ShaderGLES2::bind() {
-	if (!is_dirty())
-		return false;
 
-	conditional_version = new_conditional_version;
-	version = get_current_version();
+	if (active != this || !version || new_conditional_version.key != conditional_version.key) {
+		conditional_version = new_conditional_version;
+		version = get_current_version();
+	} else {
+		return false;
+	}
 
 	ERR_FAIL_COND_V(!version, false);
 
@@ -1107,7 +1109,3 @@ ShaderGLES2::ShaderGLES2() {
 ShaderGLES2::~ShaderGLES2() {
 	finish();
 }
-
-bool ShaderGLES2::is_dirty() const {
-	return active != this || !version || new_conditional_version.key != conditional_version.key;
-}

drivers/gles2/shader_gles2.h

@@ -208,7 +208,6 @@ public:
 	GLint get_uniform_location(int p_index) const;
 
 	static _FORCE_INLINE_ ShaderGLES2 *get_active() { return active; }
-	bool is_dirty() const;
 	bool bind();
 	void unbind();
 	void bind_uniforms();

drivers/gles2/shaders/canvas.glsl

@@ -20,6 +20,13 @@ varying vec4 color_interp;
 
 uniform highp vec2 color_texpixel_size;
 
+#ifdef USE_TEXTURE_RECT
+
+uniform vec4 dst_rect;
+uniform vec4 src_rect;
+
+#endif
+
 uniform highp float time;
 
 VERTEX_SHADER_GLOBALS
@@ -37,9 +44,35 @@ void main() {
 
 	vec4 color = color_attrib;
 
+#ifdef USE_TEXTURE_RECT
+
+	if (dst_rect.z < 0.0) { // Transpose is encoded as negative dst_rect.z
+		uv_interp = src_rect.xy + abs(src_rect.zw) * vertex.yx;
+	} else {
+		uv_interp = src_rect.xy + abs(src_rect.zw) * vertex;
+	}
+
+	vec4 outvec = vec4(0.0, 0.0, 0.0, 1.0);
+
+	// This is what is done in the GLES 3 bindings and should
+	// take care of flipped rects.
+	//
+	// But it doesn't.
+	// I don't know why, will need to investigate further.
+
+	outvec.xy = dst_rect.xy + abs(dst_rect.zw) * select(vertex, vec2(1.0, 1.0) - vertex, lessThan(src_rect.zw, vec2(0.0, 0.0)));
+
+	// outvec.xy = dst_rect.xy + abs(dst_rect.zw) * vertex;
+#else
 	vec4 outvec = vec4(vertex.xy, 0.0, 1.0);
 
+#ifdef USE_UV_ATTRIBUTE
 	uv_interp = uv_attrib;
+#else
+	uv_interp = vertex.xy;
+#endif
+
+#endif
 
 {
         vec2 src_vtx=outvec.xy;