Configurable World Shader Commands System

assets/test/shaders/demo_7_shader_command.frag.glsl

@@ -0,0 +1,12 @@
+#version 330
+
+in vec2 tex_coord;
+out vec4 frag_color;
+
+uniform float time;
+
+void main() {
+	// PLACEHOLDER: color
+	// PLACEHOLDER: alpha
+	frag_color = vec4(r, g, b, alpha);
+}

assets/test/shaders/demo_7_shader_command.vert.glsl

@@ -0,0 +1,9 @@
+#version 330
+
+in vec2 position;
+out vec2 tex_coord;
+
+void main() {
+	tex_coord = position.xy * 0.5 + 0.5;
+	gl_Position = vec4(position.xy, 0.0, 1.0);
+}

assets/test/shaders/demo_7_snippets/alpha.snippet

@@ -0,0 +1 @@
+float alpha = (sin(time) + 1.0) * 0.5;

assets/test/shaders/demo_7_snippets/color.snippet

@@ -0,0 +1,3 @@
+float r = 0.5 + 0.5 * sin(time);
+float g = 0.5 + 0.5 * sin(time + 2.0);
+float b = 0.5 + 0.5 * sin(time + 4.0);

libopenage/renderer/demo/CMakeLists.txt

@@ -6,6 +6,7 @@ add_sources(libopenage
     demo_4.cpp
     demo_5.cpp
     demo_6.cpp
+    demo_7.cpp
     stresstest_0.cpp
     stresstest_1.cpp
 	tests.cpp

libopenage/renderer/demo/demo_7.cpp

@@ -0,0 +1,85 @@
+// Copyright 2025-2025 the openage authors. See copying.md for legal info.
+
+#include "demo_7.h"
+
+#include "util/path.h"
+
+#include "renderer/demo/util.h"
+#include "renderer/gui/integration/public/gui_application_with_logger.h"
+#include "renderer/opengl/window.h"
+#include "renderer/render_pass.h"
+#include "renderer/render_target.h"
+#include "renderer/resources/mesh_data.h"
+#include "renderer/resources/shader_source.h"
+#include "renderer/shader_program.h"
+#include "renderer/stages/world/shader_template.h"
+
+namespace openage::renderer::tests {
+
+void renderer_demo_7(const util::Path &path) {
+	// Basic setup
+	auto qtapp = std::make_shared<gui::GuiApplicationWithLogger>();
+	window_settings settings;
+	settings.width = 800;
+	settings.height = 600;
+	settings.debug = true;
+
+	opengl::GlWindow window("Shader Commands Demo", settings);
+	auto renderer = window.make_renderer();
+
+	auto shaderdir = path / "assets" / "test" / "shaders";
+
+	// Initialize shader templlalte
+	world::ShaderTemplate frag_template(shaderdir / "demo_7_shader_command.frag.glsl");
+
+	// Load snippets from a snippet directory
+	frag_template.load_snippets(shaderdir / "demo_7_snippets");
+
+	auto vert_shader_file = (shaderdir / "demo_7_shader_command.vert.glsl").open();
+	auto vert_shader_src = resources::ShaderSource(
+		resources::shader_lang_t::glsl,
+		resources::shader_stage_t::vertex,
+		vert_shader_file.read());
+	vert_shader_file.close();
+
+	auto frag_shader_src = resources::ShaderSource(
+		resources::shader_lang_t::glsl,
+		resources::shader_stage_t::fragment,
+		frag_template.generate_source());
+
+	auto shader = renderer->add_shader({vert_shader_src, frag_shader_src});
+
+	// Create a simple quad for rendering
+	auto quad = renderer->add_mesh_geometry(resources::MeshData::make_quad());
+
+	auto uniforms = shader->new_uniform_input("time", 0.0f);
+
+	Renderable display_obj{
+		uniforms,
+		quad,
+		false,
+		false,
+	};
+
+	if (not check_uniform_completeness({display_obj})) {
+		log::log(WARN << "Uniforms not complete.");
+	}
+
+	auto pass = renderer->add_render_pass({display_obj}, renderer->get_display_target());
+
+	// Main loop
+	float time = 0.0f;
+	while (not window.should_close()) {
+		time += 0.016f;
+		uniforms->update("time", time);
+
+		renderer->render(pass);
+		window.update();
+		qtapp->process_events();
+
+		renderer->check_error();
+	}
+	window.close();
+}
+
+} // namespace openage::renderer::tests

libopenage/renderer/demo/demo_7.h

@@ -0,0 +1,22 @@
+// Copyright 2025-2025 the openage authors. See copying.md for legal info.
+
+#pragma once
+
+#include "util/path.h"
+
+namespace openage::renderer::tests {
+
+/**
+ * Demonstrate the shader template system for shader generation.
+ *     - Window creation
+ *     - Create a shader template
+ *     - Load shader snippets (command) from files
+ *     - Generate shader sources from the template
+ *     - Creating a render pass
+ *     - Creating a renderable from a mesh
+ *
+ * @param path Path to the project rootdir.
+ */
+void renderer_demo_7(const util::Path &path);
+
+} // namespace openage::renderer::tests

libopenage/renderer/demo/tests.cpp

@@ -1,4 +1,4 @@
-// Copyright 2015-2024 the openage authors. See copying.md for legal info.
+// Copyright 2015-2025 the openage authors. See copying.md for legal info.
 
 #include "tests.h"
 
@@ -12,6 +12,7 @@
 #include "renderer/demo/demo_4.h"
 #include "renderer/demo/demo_5.h"
 #include "renderer/demo/demo_6.h"
+#include "renderer/demo/demo_7.h"
 #include "renderer/demo/stresstest_0.h"
 #include "renderer/demo/stresstest_1.h"
 
@@ -47,6 +48,10 @@ void renderer_demo(int demo_id, const util::Path &path) {
 		renderer_demo_6(path);
 		break;
 
+	case 7:
+		renderer_demo_7(path);
+		break;
+
 	default:
 		log::log(MSG(err) << "Unknown renderer demo requested: " << demo_id << ".");
 		break;

libopenage/renderer/stages/world/CMakeLists.txt

@@ -2,4 +2,5 @@ add_sources(libopenage
 	object.cpp
 	render_entity.cpp
 	render_stage.cpp
+	shader_template.cpp
 )

libopenage/renderer/stages/world/shader_template.cpp

@@ -0,0 +1,65 @@
+// Copyright 2024-2025 the openage authors. See copying.md for legal info.
+
+#include "shader_template.h"
+
+#include <cstring>
+
+#include "error/error.h"
+#include "log/log.h"
+
+namespace openage::renderer::world {
+
+ShaderTemplate::ShaderTemplate(const util::Path &template_path) {
+	auto file = template_path.open();
+	this->template_code = file.read();
+	file.close();
+}
+
+void ShaderTemplate::load_snippets(const util::Path &snippet_path) {
+	// load config here
+	util::Path snippet_path_copy = snippet_path;
+	for (const auto &entry : snippet_path_copy.iterdir()) {
+		if (entry.get_name().ends_with(".snippet")) {
+			add_snippet(entry);
+		}
+	}
+}
+
+void ShaderTemplate::add_snippet(const util::Path &snippet_path) {
+	std::string file_name = snippet_path.get_name();
+	std::string name = file_name.substr(0, file_name.find_last_of('.'));
+	auto file = snippet_path.open();
+	std::string content = file.read();
+	file.close();
+
+	snippets[name] = content;
+}
+
+std::string ShaderTemplate::generate_source() const {
+	std::string result = template_code;
+
+	// Process each placeholder
+	for (const auto &[name, snippet_code] : snippets) {
+		std::string placeholder = "// PLACEHOLDER: " + name;
+		size_t pos = result.find(placeholder);
+
+		if (pos != std::string::npos) {
+			result.replace(pos, placeholder.length(), snippet_code);
+		}
+		else {
+			log::log(WARN << "Placeholder not found in template: " << name);
+		}
+	}
+
+	// Check if all placeholders were replaced
+	size_t placeholder_pos = result.find("// PLACEHOLDER:");
+	if (placeholder_pos != std::string::npos) {
+		size_t line_end = result.find('\n', placeholder_pos);
+		std::string missing = result.substr(placeholder_pos,
+		                                    line_end - placeholder_pos);
+		throw Error(MSG(err) << "Missing snippet for placeholder: " << missing);
+	}
+
+	return result;
+}
+} // namespace openage::renderer::world

libopenage/renderer/stages/world/shader_template.h

@@ -0,0 +1,62 @@
+// Copyright 2024-2025 the openage authors. See copying.md for legal info.
+
+#pragma once
+
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "util/path.h"
+
+namespace openage {
+namespace renderer {
+namespace world {
+
+/**
+ * Manages shader templates and their code snippets.
+ * Allows loading configurable shader commands and generating
+ * complete shader source code.
+ */
+class ShaderTemplate {
+public:
+	/**
+	 * Create a shader template from source code of shader.
+	 *
+	 * @param template_path Path to the template file.
+	 */
+	explicit ShaderTemplate(const util::Path &template_path);
+
+	/**
+	 * Load all snippets from a JSON config file.
+	 *
+	 * @param config_path Path to JSON config file.
+	 * @param base_path Base path for resolving relative snippet paths.
+	 */
+	void load_snippets(const util::Path &snippet_path);
+
+	/**
+	 * Add a single code snippet to snippets map.
+	 *
+	 * @param name Snippet identifier.
+	 * @param snippet_path Path to the snippet file.
+	 */
+	void add_snippet(const util::Path &snippet_path);
+
+	/**
+	 * Generate final shader source code with all snippets inserted.
+	 *
+	 * @return Complete shader code.
+	 * @throws Error if any required placeholders are missing snippets.
+	 */
+	std::string generate_source() const;
+
+private:
+	// Original template code with placeholders
+	std::string template_code;
+	// Mapping of placeholder IDs to their code snippets
+	std::map<std::string, std::string> snippets;
+};
+} // namespace world
+} // namespace renderer
+} // namespace openage