Create Shader class as a base for vertex and pixel shader

1 files changed, 79 insertions, 0 deletions

diff --git a/include/RenderBackend/OpenGL/Shader.hpp b/include/RenderBackend/OpenGL/Shader.hpp
new file mode 100644
index 0000000..7aecc4e
--- /dev/null
+++ b/include/RenderBackend/OpenGL/Shader.hpp
@@ -0,0 +1,79 @@
+#pragma once
+
+#include "../../DataView.hpp"
+#include "../../utils.hpp"
+#include "../../Result.hpp"
+#include "CommonShader.hpp"
+#include "ShaderVec.hpp"
+#include <string>
+#include <unordered_map>
+#include <vector>
+#include <stdexcept>
+#include <functional>
+
+namespace amalgine {
+    class ShaderTooManyAttributes : public std::runtime_error
+    {
+    public:
+        ShaderTooManyAttributes(i32 maxAttributes);
+    };
+    
+    class ShaderAttributeAlreadyDefined : public std::runtime_error
+    {
+    public:
+        ShaderAttributeAlreadyDefined(const std::string &attributeName);
+    };
+    
+    class ShaderInvalidAttributeName : public std::runtime_error
+    {
+    public:
+        ShaderInvalidAttributeName(const std::string &attributeName);
+    };
+    
+    class ShaderFunctionAlreadyDefined : public std::runtime_error
+    {
+    public:
+        ShaderFunctionAlreadyDefined(const std::string &funcName);
+    };
+    
+    class Shader
+    {
+        DISABLE_COPY(Shader)
+        friend class ShaderProgram;
+    public:
+        Shader();
+        
+        const std::string& getOutputAttributeName(i32 attributeIndex);
+        const std::string& getInputAttributeName(i32 attributeIndex) const;
+        AttributeType getInputAttributeType(i32 attributeIndex) const;
+        ShaderOutputVec4 defineOutputVec4(const std::string &name);
+        ShaderGlobalVec3 defineGlobalVec3(const std::string &name);
+        ShaderInputVec2 defineInputVec2(const std::string &name);
+        i32 defineInputVariable(const std::string &variableName, const char *typeName);
+        
+        void assign(const ShaderOutputVec4 &lhsVariable, const ShaderVec4 &rhsVariable);
+    protected:
+        void writeHeader(const std::string &code);
+        void writeBody(const std::string &code);
+        std::string build() const;
+        
+        /*
+         * Throws ShaderTooManyAttributes if too many attributes are defined for the platform.
+         * Throws ShaderAttributeAlreadyDefined if a attribute with the same name has already been defined.
+         */
+        i32 defineOutputVariable(const std::string &variableName, const char *typeName);
+    protected:
+        std::string header;
+        std::string body;
+        int inputLocationCounter;
+        int outputLocationCounter;
+        // TOOD: Verify if this is correct. This same variable is used for both output and input variables
+        i32 maxAttribs; // Could make this static
+        std::unordered_map<std::string, i32> inputAttributes;
+        std::vector<ShaderAttribute> inputAttributeNames;
+        std::unordered_map<std::string, i32> outputAttributes;
+        std::vector<ShaderAttribute> outputAttributeNames;
+        std::unordered_map<std::string, ShaderGlobalVec> uniforms;
+        bool mainFuncDefined;
+    };
+}