From 057aa57422e520c1f3bd54bbd8bf071d749d0fd4 Mon Sep 17 00:00:00 2001
From: wheremyfoodat <gponiris2004@gmail.com>
Date: Fri, 23 Sep 2022 02:43:51 +0300
Subject: [PATCH] [PICA] Start implementing shader interpreter

---
 CMakeLists.txt                       |  4 +++-
 include/PICA/shader.hpp              |  9 +++++++--
 include/PICA/shader_unit.hpp         |  5 +++--
 src/core/PICA/gpu.cpp                |  6 +++++-
 src/core/PICA/shader_interpreter.cpp | 14 ++++++++++++++
 5 files changed, 32 insertions(+), 6 deletions(-)
 create mode 100644 src/core/PICA/shader_interpreter.cpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index e084e7e0..3f0d30c8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -54,7 +54,9 @@ set(SERVICE_SOURCE_FILES src/core/services/service_manager.cpp src/core/services
                          src/core/services/fs.cpp src/core/services/gsp_gpu.cpp src/core/services/gsp_lcd.cpp
                          src/core/services/ndm.cpp
 )
-set(PICA_SOURCE_FILES src/core/PICA/gpu.cpp src/core/PICA/regs.cpp src/core/PICA/shader_unit.cpp)
+set(PICA_SOURCE_FILES src/core/PICA/gpu.cpp src/core/PICA/regs.cpp src/core/PICA/shader_unit.cpp
+                      src/core/PICA/shader_interpreter.cpp
+)
 
 set(HEADER_FILES include/emulator.hpp include/helpers.hpp include/opengl.hpp include/termcolor.hpp
                  include/cpu.hpp include/cpu_dynarmic.hpp include/memory.hpp include/kernel/kernel.hpp
diff --git a/include/PICA/shader.hpp b/include/PICA/shader.hpp
index 8a876a95..e521b057 100644
--- a/include/PICA/shader.hpp
+++ b/include/PICA/shader.hpp
@@ -10,12 +10,13 @@ enum class ShaderType {
 	Vertex, Geometry
 };
 
-template <ShaderType type>
 class PICAShader {
-	int bufferIndex; // Index of the next instruction to overwrite
 	using f24 = Floats::f24;
 	using vec4f = OpenGL::Vector<f24, 4>;
 
+	int bufferIndex; // Index of the next instruction to overwrite for shader uploads
+	ShaderType type;
+
 public:
 	std::array<u32, 512> loadedShader; // Currently loaded & active shader
 	std::array<u32, 512> bufferedShader; // Shader to be transferred when the SH_CODETRANSFER_END reg gets written to
@@ -28,6 +29,8 @@ public:
 	std::array<vec4f, 16> attributes; // Attributes past to the shader
 	std::array<vec4f, 16> outputs;
 
+	PICAShader(ShaderType type) : type(type) {}
+
 	void reset() {
 		loadedShader.fill(0);
 		bufferedShader.fill(0);
@@ -55,4 +58,6 @@ public:
 		bufferedShader[bufferIndex++] = word;
 		bufferIndex &= 511;
 	}
+
+	void run();
 };
\ No newline at end of file
diff --git a/include/PICA/shader_unit.hpp b/include/PICA/shader_unit.hpp
index b1e7e3f2..d8d93160 100644
--- a/include/PICA/shader_unit.hpp
+++ b/include/PICA/shader_unit.hpp
@@ -4,8 +4,9 @@
 class ShaderUnit {
 
 public:
-	PICAShader<ShaderType::Vertex> vs; // Vertex shader
-	PICAShader<ShaderType::Geometry> gs; // Geometry shader
+	PICAShader vs; // Vertex shader
+	PICAShader gs; // Geometry shader
 
+	ShaderUnit() : vs(ShaderType::Vertex), gs(ShaderType::Geometry) {}
 	void reset();
 };
\ No newline at end of file
diff --git a/src/core/PICA/gpu.cpp b/src/core/PICA/gpu.cpp
index f8cd60ef..80733b55 100644
--- a/src/core/PICA/gpu.cpp
+++ b/src/core/PICA/gpu.cpp
@@ -71,7 +71,9 @@ void GPU::drawArrays() {
 		for (int attrCount = 0; attrCount < totalAttribCount; attrCount++) {
 			// Check if attribute is fixed or not
 			if (fixedAttribMask & (1 << attrCount)) { // Fixed attribute
-
+				vec4f& fixedAttr = shaderUnit.vs.fixedAttributes[attrCount]; // TODO: Is this how it works?
+				vec4f& inputAttr = shaderUnit.vs.attributes[attrCount];
+				std::memcpy(&inputAttr, &fixedAttr, sizeof(vec4f)); // Copy fixed attr to input attr
 			} else { // Non-fixed attribute
 				auto& attr = attributeInfo[attrCount]; // Get information for this attribute
 				u64 attrCfg = attr.getConfigFull(); // Get config1 | (config2 << 32)
@@ -113,5 +115,7 @@ void GPU::drawArrays() {
 				printf("Attribute %d, type: %d, component count: %d\n", attrCount, attribType, componentCount);
 			}
 		}
+
+		shaderUnit.vs.run(); // Run vertex shader for vertex
 	}
 }
\ No newline at end of file
diff --git a/src/core/PICA/shader_interpreter.cpp b/src/core/PICA/shader_interpreter.cpp
new file mode 100644
index 00000000..f1ca0601
--- /dev/null
+++ b/src/core/PICA/shader_interpreter.cpp
@@ -0,0 +1,14 @@
+#include "PICA/shader.hpp"
+
+void PICAShader::run() {
+	u32 pc = 0; // Program counter
+
+	while (true) {
+		const u32 instruction = loadedShader[pc++];
+		const u32 opcode = instruction >> 26; // Top 6 bits are the opcode
+
+		switch (opcode) {
+			default:Helpers::panic("Unimplemented PICA instruction %08X (Opcode = %02X)", instruction, opcode);
+		}
+	}
+}
\ No newline at end of file