From cd9114bfd0ea23fcf6ea9f38621099113352e9c6 Mon Sep 17 00:00:00 2001
From: Henrik Hautakoski <henrik.hautakoski@gmail.com>
Date: Sun, 18 Sep 2022 12:26:01 +0200
Subject: [PATCH] Adding Spectre/GfxDriver/ShaderProgram base class.

---
 include/Spectre/GfxDriver/ShaderProgram.h | 77 +++++++++++++++++++++++
 source/GfxDriver/ShaderProgram.cpp        | 69 ++++++++++++++++++++
 2 files changed, 146 insertions(+)
 create mode 100644 include/Spectre/GfxDriver/ShaderProgram.h
 create mode 100644 source/GfxDriver/ShaderProgram.cpp

diff --git a/include/Spectre/GfxDriver/ShaderProgram.h b/include/Spectre/GfxDriver/ShaderProgram.h
new file mode 100644
index 0000000..872e137
--- /dev/null
+++ b/include/Spectre/GfxDriver/ShaderProgram.h
@@ -0,0 +1,77 @@
+
+#ifndef SPECTRE_GFXDRIVER_SHADERPROGRAM_H
+#define SPECTRE_GFXDRIVER_SHADERPROGRAM_H
+
+#include <Spectre/Math/Matrix4.h>
+#include <Spectre/Math/Color.h>
+
+namespace sp {
+
+enum ShaderType {
+	Vertex,
+	Fragment
+};
+
+class ShaderProgram
+{
+public:
+	virtual ~ShaderProgram();
+
+	// Load a shader program from file.
+	virtual bool loadFromFile(const std::string& filename);
+
+	// Load a shader from file.
+	virtual bool loadFromFile(const std::string& filename, ShaderType type);
+
+	// Load a shader from memory.
+	virtual bool loadFromMemory(const std::string& source, ShaderType type) = 0;
+
+	// Link the program.
+	virtual bool link() = 0;
+
+	// Returns true if the program was linked successfully
+	virtual bool isLinked() const;
+
+	// Enable this shader
+	// All shader operations after this call will affect this shader.
+	virtual void enable() const = 0;
+
+	// Disable this shader
+	// Operations will no longer affect this shader after this call.
+	virtual void disable() const = 0;
+
+	// Get the last shader error.
+	virtual std::string getLastError() const;
+
+	// ---------------------
+	// Variables.
+	// ---------------------
+	// TODO: Move this to a ShaderParameter class
+
+	virtual bool setMVPMatrix(const Matrix4f& matrix) = 0;
+
+	// ---------------------
+	//  General Variables.
+	// ---------------------
+
+	virtual bool setAttribute(const std::string& name, float value) const = 0;
+
+	virtual bool setAttribute(const std::string& name, const Matrix4f& matrix) const = 0;
+
+	virtual bool setUniform(const std::string& name, const Matrix4f& matrix) const = 0;
+
+	virtual bool setUniform(const std::string& name, const Color& color) const = 0;
+
+
+protected:
+
+	std::string m_extension;
+
+	mutable std::string m_error;
+
+	bool m_linked;
+};
+
+} // namespace sp
+
+#endif /* SECTRE_GRAPHICS_SHADERPROGRAM_H */ 
diff --git a/source/GfxDriver/ShaderProgram.cpp b/source/GfxDriver/ShaderProgram.cpp
new file mode 100644
index 0000000..61ed11a
--- /dev/null
+++ b/source/GfxDriver/ShaderProgram.cpp
@@ -0,0 +1,69 @@
+
+#include <Spectre/System/Path.h>
+#include <Spectre/System/File.h>
+#include <Spectre/GfxDriver/ShaderProgram.h>
+#include <string>
+
+namespace sp 
+{
+
+ShaderProgram::~ShaderProgram()
+{
+}
+
+bool ShaderProgram::loadFromFile(const std::string& filename)
+{
+    std::string extension = Path::getExtension(filename);
+
+	// Meta file. load real shaders.
+	if (extension == "shader." + m_extension) {
+
+		// FIXME: This is ugly :)
+		std::string base_name = filename.substr(0, filename.length() - extension.length());
+
+		// vert and frag are not optional. they must exist.
+		return	loadFromFile(base_name + "vert." + m_extension, ShaderType::Vertex) &&
+			loadFromFile(base_name + "frag." + m_extension, ShaderType::Fragment);
+
+	} else if (extension == "vert." + m_extension) {
+		return loadFromFile(filename, ShaderType::Vertex);
+	} else if (extension == "frag." + m_extension) {
+		return loadFromFile(filename, ShaderType::Fragment);
+	}
+
+	m_error = "Invalid file extension: " + extension;
+
+	return false;
+}
+
+bool ShaderProgram::loadFromFile(const std::string& filename, ShaderType type)
+{
+	std::string src;
+	File file;
+
+	if (!file.open(filename)) {
+		m_error = "Can't open file: " + filename;
+		return false;
+	}
+
+	// Load file into memory.
+	if (!file.read(src)) {
+		m_error = "Could not read file: " + filename;
+		return false;
+	}
+
+	return loadFromMemory(src, type);
+}
+
+
+bool  ShaderProgram::isLinked() const
+{
+    return m_linked;
+}
+
+std::string ShaderProgram::getLastError() const
+{
+    return m_error;
+}
+
+} // namespace sp
\ No newline at end of file