diff --git a/include/PICA/gpu.hpp b/include/PICA/gpu.hpp
index 501fe37f..5c9580b7 100644
--- a/include/PICA/gpu.hpp
+++ b/include/PICA/gpu.hpp
@@ -65,7 +65,11 @@ class GPU {
 
 	std::array<AttribInfo, maxAttribCount> attributeInfo; // Info for each of the 12 attributes
 	u32 totalAttribCount = 0; // Number of vertex attributes to send to VS
-	u32 fixedAttribMask = 0;
+	u32 fixedAttribMask = 0; // Which attributes are fixed?
+	
+	u32 fixedAttribIndex = 0; // Which fixed attribute are we writing to ([0, 12] range)
+	u32 fixedAttribCount = 0; // How many attribute components have we written? When we get to 4 the attr will actually get submitted
+	std::array<u32, 3> fixedAttrBuff; // Buffer to hold fixed attributes in until they get submitted
 
 public:
 	GPU(Memory& mem);
diff --git a/include/PICA/regs.hpp b/include/PICA/regs.hpp
index 6e1067f6..eacafcc9 100644
--- a/include/PICA/regs.hpp
+++ b/include/PICA/regs.hpp
@@ -41,6 +41,12 @@ namespace PICAInternalRegs {
 		AttribInfoStart = Attrib0Offset,
 		AttribInfoEnd = Attrib11Config2,
 
+		// Fixed attribute registers
+		FixedAttribIndex = 0x232,
+		FixedAttribData0 = 0x233,
+		FixedAttribData1 = 0x234,
+		FixedAttribData2 = 0x235,
+
 		// Vertex shader registers
 		VertexShaderTransferEnd = 0x2BF,
 		VertexShaderTransferIndex = 0x2CB,
diff --git a/include/PICA/shader.hpp b/include/PICA/shader.hpp
index a51e4bed..8a876a95 100644
--- a/include/PICA/shader.hpp
+++ b/include/PICA/shader.hpp
@@ -6,6 +6,11 @@
 #include "opengl.hpp"
 #include "PICA/float_types.hpp"
 
+enum class ShaderType {
+	Vertex, Geometry
+};
+
+template <ShaderType type>
 class PICAShader {
 	int bufferIndex; // Index of the next instruction to overwrite
 	using f24 = Floats::f24;
@@ -19,7 +24,8 @@ public:
 	std::array<u32, 4> intUniforms;
 	std::array<vec4f, 8> floatUniforms;
 
-	std::array<vec4f, 16> attributes;
+	std::array<vec4f, 16> fixedAttributes; // Fixed vertex attributes
+	std::array<vec4f, 16> attributes; // Attributes past to the shader
 	std::array<vec4f, 16> outputs;
 
 	void reset() {
diff --git a/include/PICA/shader_unit.hpp b/include/PICA/shader_unit.hpp
index 3fa59bfa..b1e7e3f2 100644
--- a/include/PICA/shader_unit.hpp
+++ b/include/PICA/shader_unit.hpp
@@ -4,8 +4,8 @@
 class ShaderUnit {
 
 public:
-	PICAShader vs; // Vertex shader
-	PICAShader gs; // Geometry shader
+	PICAShader<ShaderType::Vertex> vs; // Vertex shader
+	PICAShader<ShaderType::Geometry> gs; // Geometry shader
 
 	void reset();
 };
\ No newline at end of file
diff --git a/src/core/PICA/gpu.cpp b/src/core/PICA/gpu.cpp
index 840b6317..f8cd60ef 100644
--- a/src/core/PICA/gpu.cpp
+++ b/src/core/PICA/gpu.cpp
@@ -7,8 +7,18 @@ using namespace Floats;
 
 GPU::GPU(Memory& mem) : mem(mem) {
 	vram = new u8[vramSize];
+}
+
+void GPU::reset() {
+	regs.fill(0);
+	shaderUnit.reset();
+	std::memset(vram, 0, vramSize);
+
 	totalAttribCount = 0;
 	fixedAttribMask = 0;
+	fixedAttribIndex = 0;
+	fixedAttribCount = 0;
+	fixedAttrBuff.fill(0);
 
 	for (auto& e : attributeInfo) {
 		e.offset = 0;
@@ -16,12 +26,7 @@ GPU::GPU(Memory& mem) : mem(mem) {
 		e.config1 = 0;
 		e.config2 = 0;
 	}
-}
 
-void GPU::reset() {
-	regs.fill(0);
-	shaderUnit.reset();
-	std::memset(vram, 0, vramSize);
 	// TODO: Reset blending, texturing, etc here
 }
 
diff --git a/src/core/PICA/regs.cpp b/src/core/PICA/regs.cpp
index 0c72935c..b8ab7417 100644
--- a/src/core/PICA/regs.cpp
+++ b/src/core/PICA/regs.cpp
@@ -1,6 +1,8 @@
 #include "PICA/gpu.hpp"
 #include "PICA/regs.hpp"
 
+using namespace Floats;
+
 u32 GPU::readReg(u32 address) {
 	printf("Ignoring read from GPU register %08X\n", address);
 	return 0;
@@ -52,6 +54,34 @@ void GPU::writeInternalReg(u32 index, u32 value, u32 mask) {
 			fixedAttribMask = (value >> 16) & 0xfff; // Determines which vertex attributes are fixed for all vertices
 			break;
 
+		case FixedAttribIndex:
+			fixedAttribCount = 0;
+			fixedAttribIndex = value & 0xf;
+
+			if (fixedAttribIndex == 0xf) Helpers::panic("[PICA] Immediate mode vertex submission");
+			break;
+
+		case FixedAttribData0: case FixedAttribData1: case FixedAttribData2:
+			if (fixedAttribIndex >= 12) Helpers::panic("[PICA] Tried to write to fixed attribute %d", fixedAttribIndex);
+
+			fixedAttrBuff[fixedAttribCount++] = value;
+			if (fixedAttribCount == 3) {
+				fixedAttribCount = 0;
+
+				vec4f& attr = shaderUnit.vs.fixedAttributes[fixedAttribIndex];
+				// These are stored in the reverse order anyone would expect them to be in
+				attr.x() = f24::fromRaw(fixedAttrBuff[2] & 0xffffff);
+				attr.y() = f24::fromRaw(((fixedAttrBuff[1] & 0xffff) << 8) | (fixedAttrBuff[2] >> 24));
+				attr.z() = f24::fromRaw(((fixedAttrBuff[0] & 0xff) << 16) | (fixedAttrBuff[1] >> 16));
+				attr.w() = f24::fromRaw(fixedAttrBuff[0] >> 8);
+
+				printf("r: %f g: %f b: %f a: %f\n", (double)attr.r().toFloat32(), (double)attr.g().toFloat32(), (double)attr.b().toFloat32(), (double)attr.a().toFloat32());
+
+				fixedAttribIndex++;
+			}
+
+			break;
+
 		case VertexShaderTransferEnd:
 			if (value != 0) shaderUnit.vs.finalize();
 			break;