Add clipping, backbuffer, and CanvasGroups to 2D GLES3 renderer

As well as significant consequent cleanup in the RenderTarget, Texture, and Canvas renderer code

3 files changed, 242 insertions, 0 deletions

diff --git a/drivers/gles3/effects/SCsub b/drivers/gles3/effects/SCsub
new file mode 100644
index 0000000000..91e1140b75
--- /dev/null
+++ b/drivers/gles3/effects/SCsub
@@ -0,0 +1,5 @@
+#!/usr/bin/env python
+
+Import("env")
+
+env.add_source_files(env.drivers_sources, "*.cpp")
diff --git a/drivers/gles3/effects/copy_effects.cpp b/drivers/gles3/effects/copy_effects.cpp
new file mode 100644
index 0000000000..c8e6c2b476
--- /dev/null
+++ b/drivers/gles3/effects/copy_effects.cpp
@@ -0,0 +1,164 @@
+/*************************************************************************/
+/*  copy_effects.cpp                                                     */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifdef GLES3_ENABLED
+
+#include "copy_effects.h"
+
+using namespace GLES3;
+
+CopyEffects *CopyEffects::singleton = nullptr;
+
+CopyEffects *CopyEffects::get_singleton() {
+	return singleton;
+}
+
+CopyEffects::CopyEffects() {
+	singleton = this;
+
+	copy.shader.initialize();
+	copy.shader_version = copy.shader.version_create();
+	copy.shader.version_bind_shader(copy.shader_version, CopyShaderGLES3::MODE_DEFAULT);
+
+	{ // Screen Triangle.
+		glGenBuffers(1, &screen_triangle);
+		glBindBuffer(GL_ARRAY_BUFFER, screen_triangle);
+
+		const float qv[6] = {
+			-1.0f,
+			-1.0f,
+			3.0f,
+			-1.0f,
+			-1.0f,
+			3.0f,
+		};
+
+		glBufferData(GL_ARRAY_BUFFER, sizeof(float) * 6, qv, GL_STATIC_DRAW);
+		glBindBuffer(GL_ARRAY_BUFFER, 0); //unbind
+
+		glGenVertexArrays(1, &screen_triangle_array);
+		glBindVertexArray(screen_triangle_array);
+		glBindBuffer(GL_ARRAY_BUFFER, screen_triangle);
+		glVertexAttribPointer(RS::ARRAY_VERTEX, 2, GL_FLOAT, GL_FALSE, sizeof(float) * 2, nullptr);
+		glEnableVertexAttribArray(RS::ARRAY_VERTEX);
+		glBindVertexArray(0);
+		glBindBuffer(GL_ARRAY_BUFFER, 0); //unbind
+	}
+
+	{ // Screen Quad
+
+		glGenBuffers(1, &quad);
+		glBindBuffer(GL_ARRAY_BUFFER, quad);
+
+		const float qv[12] = {
+			-1.0f,
+			-1.0f,
+			1.0f,
+			-1.0f,
+			1.0f,
+			1.0f,
+			-1.0f,
+			-1.0f,
+			1.0f,
+			1.0f,
+			-1.0f,
+			1.0f,
+		};
+
+		glBufferData(GL_ARRAY_BUFFER, sizeof(float) * 12, qv, GL_STATIC_DRAW);
+		glBindBuffer(GL_ARRAY_BUFFER, 0); //unbind
+
+		glGenVertexArrays(1, &quad_array);
+		glBindVertexArray(quad_array);
+		glBindBuffer(GL_ARRAY_BUFFER, quad);
+		glVertexAttribPointer(RS::ARRAY_VERTEX, 2, GL_FLOAT, GL_FALSE, sizeof(float) * 2, nullptr);
+		glEnableVertexAttribArray(RS::ARRAY_VERTEX);
+		glBindVertexArray(0);
+		glBindBuffer(GL_ARRAY_BUFFER, 0); //unbind
+	}
+}
+
+CopyEffects::~CopyEffects() {
+	singleton = nullptr;
+	glDeleteBuffers(1, &screen_triangle);
+	glDeleteVertexArrays(1, &screen_triangle_array);
+	glDeleteBuffers(1, &quad);
+	glDeleteVertexArrays(1, &quad_array);
+}
+
+void CopyEffects::copy_to_rect(const Rect2i &p_rect) {
+	copy.shader.version_bind_shader(copy.shader_version, CopyShaderGLES3::MODE_COPY_SECTION);
+	copy.shader.version_set_uniform(CopyShaderGLES3::COPY_SECTION, p_rect.position.x, p_rect.position.y, p_rect.size.x, p_rect.size.y, copy.shader_version, CopyShaderGLES3::MODE_COPY_SECTION);
+	glBindVertexArray(quad_array);
+	glDrawArrays(GL_TRIANGLES, 0, 6);
+	glBindVertexArray(0);
+}
+
+void CopyEffects::copy_screen() {
+	copy.shader.version_bind_shader(copy.shader_version, CopyShaderGLES3::MODE_DEFAULT);
+	glBindVertexArray(screen_triangle_array);
+	glDrawArrays(GL_TRIANGLES, 0, 3);
+	glBindVertexArray(0);
+}
+
+void CopyEffects::bilinear_blur(GLuint p_source_texture, int p_mipmap_count, const Rect2i &p_region) {
+	GLuint framebuffers[2];
+	glGenFramebuffers(2, framebuffers);
+	glBindFramebuffer(GL_READ_FRAMEBUFFER, framebuffers[0]);
+	glFramebufferTexture2D(GL_READ_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, p_source_texture, 0);
+
+	Rect2i source_region = p_region;
+	Rect2i dest_region = p_region;
+	for (int i = 1; i < p_mipmap_count; i++) {
+		dest_region.position.x >>= 1;
+		dest_region.position.y >>= 1;
+		dest_region.size.x = MAX(1, dest_region.size.x >> 1);
+		dest_region.size.y = MAX(1, dest_region.size.y >> 1);
+		glBindFramebuffer(GL_DRAW_FRAMEBUFFER, framebuffers[i % 2]);
+		glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, p_source_texture, i);
+		glBlitFramebuffer(source_region.position.x, source_region.position.y, source_region.size.x, source_region.size.y,
+				dest_region.position.x, dest_region.position.y, dest_region.size.x, dest_region.size.y, GL_COLOR_BUFFER_BIT, GL_LINEAR);
+		glBindFramebuffer(GL_READ_FRAMEBUFFER, framebuffers[i % 2]);
+		source_region = dest_region;
+	}
+	glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
+	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
+	glDeleteFramebuffers(2, framebuffers);
+}
+
+void CopyEffects::set_color(const Color &p_color, const Rect2i &p_region) {
+	copy.shader.version_bind_shader(copy.shader_version, CopyShaderGLES3::MODE_SIMPLE_COLOR);
+	copy.shader.version_set_uniform(CopyShaderGLES3::COPY_SECTION, p_region.position.x, p_region.position.y, p_region.size.x, p_region.size.y, copy.shader_version, CopyShaderGLES3::MODE_SIMPLE_COLOR);
+	copy.shader.version_set_uniform(CopyShaderGLES3::COLOR_IN, p_color, copy.shader_version, CopyShaderGLES3::MODE_SIMPLE_COLOR);
+	glBindVertexArray(quad_array);
+	glDrawArrays(GL_TRIANGLES, 0, 6);
+	glBindVertexArray(0);
+}
+#endif // GLES3_ENABLED
diff --git a/drivers/gles3/effects/copy_effects.h b/drivers/gles3/effects/copy_effects.h
new file mode 100644
index 0000000000..1cf1ac9404
--- /dev/null
+++ b/drivers/gles3/effects/copy_effects.h
@@ -0,0 +1,73 @@
+/*************************************************************************/
+/*  copy_effects.h                                                       */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef COPY_GL_H
+#define COPY_GL_H
+
+#ifdef GLES3_ENABLED
+
+#include "../shaders/copy.glsl.gen.h"
+
+namespace GLES3 {
+
+class CopyEffects {
+private:
+	struct Copy {
+		CopyShaderGLES3 shader;
+		RID shader_version;
+	} copy;
+
+	static CopyEffects *singleton;
+
+	// Use for full-screen effects. Slightly more efficient than screen_quad as this eliminates pixel overdraw along the diagonal.
+	GLuint screen_triangle = 0;
+	GLuint screen_triangle_array = 0;
+
+	// Use for rect-based effects.
+	GLuint quad = 0;
+	GLuint quad_array = 0;
+
+public:
+	static CopyEffects *get_singleton();
+
+	CopyEffects();
+	~CopyEffects();
+
+	// These functions assume that a framebuffer and texture are bound already. They only manage the shader, uniforms, and vertex array.
+	void copy_to_rect(const Rect2i &p_rect);
+	void copy_screen();
+	void bilinear_blur(GLuint p_source_texture, int p_mipmap_count, const Rect2i &p_region);
+	void set_color(const Color &p_color, const Rect2i &p_region);
+};
+
+} //namespace GLES3
+
+#endif // GLES3_ENABLED
+#endif // !COPY_GL_H