From c048221f866052fe4c3762bb321d0ed6827ed459 Mon Sep 17 00:00:00 2001
From: fincs <fincs.alt1@gmail.com>
Date: Sat, 5 Dec 2015 13:28:41 +0100
Subject: [PATCH] Add shaderProgramSetGshMode() for configuring geoshader mode

---
 libctru/include/3ds/gpu/shaderProgram.h | 17 +++++++++++++++++
 libctru/source/gpu/shaderProgram.c      | 22 +++++++++++++++++++---
 2 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/libctru/include/3ds/gpu/shaderProgram.h b/libctru/include/3ds/gpu/shaderProgram.h
index 70d2457..90f1692 100644
--- a/libctru/include/3ds/gpu/shaderProgram.h
+++ b/libctru/include/3ds/gpu/shaderProgram.h
@@ -33,8 +33,18 @@ typedef struct
 	shaderInstance_s* geometryShader; ///< Geometry shader.
 	u32 geoShaderInputPermutation[2]; ///< Geometry shader input permutation.
 	u8 geoShaderInputStride;          ///< Geometry shader input stride.
+	u8 geoShaderMode;                 ///< Geometry shader operation mode.
 }shaderProgram_s;
 
+/// Geometry shader operation modes.
+typedef enum
+{
+	GSH_NORMAL                    = 0, ///< Normal operation.
+	GSH_PARTICLE                  = 1, ///< Particle system.
+	GSH_SUBDIVISION_LOOP          = 2, ///< Loop subdivision surface.
+	GSH_SUBDIVISION_CATMULL_CLARK = 3, ///< Catmull-Clark subdivision surface.
+} geoShaderMode;
+
 /**
  * @brief Initializes a shader instance.
  * @param si Shader instance to initialize.
@@ -105,6 +115,13 @@ Result shaderProgramSetGsh(shaderProgram_s* sp, DVLE_s* dvle, u8 stride);
  */
 Result shaderProgramSetGshInputPermutation(shaderProgram_s* sp, u64 permutation);
 
+/**
+ * @brief Configures the operation mode of the geometry shader of a shader program.
+ * @param sp Shader program to use.
+ * @param mode Operation mode to use.
+ */
+Result shaderProgramSetGshMode(shaderProgram_s* sp, geoShaderMode mode);
+
 /**
  * @brief Configures the shader units to use the specified shader program.
  * @param sp Shader program to use.
diff --git a/libctru/source/gpu/shaderProgram.c b/libctru/source/gpu/shaderProgram.c
index a891dcb..8b2c34e 100644
--- a/libctru/source/gpu/shaderProgram.c
+++ b/libctru/source/gpu/shaderProgram.c
@@ -168,6 +168,7 @@ Result shaderProgramSetGsh(shaderProgram_s* sp, DVLE_s* dvle, u8 stride)
 	sp->geoShaderInputPermutation[0] = 0x76543210;
 	sp->geoShaderInputPermutation[1] = 0xFEDCBA98;
 	sp->geoShaderInputStride = stride;
+	sp->geoShaderMode = GSH_NORMAL;
 
 	return shaderInstanceInit(sp->geometryShader, dvle);
 }
@@ -181,6 +182,14 @@ Result shaderProgramSetGshInputPermutation(shaderProgram_s* sp, u64 permutation)
 	return 0;
 }
 
+Result shaderProgramSetGshMode(shaderProgram_s* sp, geoShaderMode mode)
+{
+	if(!sp || !sp->geometryShader)return -1;
+
+	sp->geoShaderMode = mode & 3;
+	return 0;
+}
+
 Result shaderProgramConfigure(shaderProgram_s* sp, bool sendVshCode, bool sendGshCode)
 {
 	if(!sp)return -1;
@@ -212,8 +221,15 @@ Result shaderProgramConfigure(shaderProgram_s* sp, bool sendVshCode, bool sendGs
 	GPUCMD_AddWrite(GPUREG_VSH_OUTMAP_TOTAL1, vshDvle->outmapData[0]-1); // ?
 	GPUCMD_AddWrite(GPUREG_VSH_OUTMAP_TOTAL2, vshDvle->outmapData[0]-1); // ?
 
-	GPUCMD_AddMaskedWrite(GPUREG_GEOSTAGE_CONFIG, 0x8, 0x00000000); // ?
-	GPUCMD_AddWrite(GPUREG_GSH_MISC0, 0x00000000); // ?
+	bool subdivision = sp->geoShaderMode >= GSH_SUBDIVISION_LOOP;
+	GPUCMD_AddMaskedWrite(GPUREG_GEOSTAGE_CONFIG, 0x8, subdivision ? 0x80000000 : 0); // Enable or disable subdivision
+	u32 gshMisc = 0;
+	if (subdivision)
+		gshMisc = 1;
+	else if (sp->geoShaderMode == GSH_PARTICLE)
+		gshMisc = 0x01004302;
+	GPUCMD_AddWrite(GPUREG_GSH_MISC0, gshMisc);
+	GPUCMD_AddWrite(GPUREG_GSH_MISC1, sp->geoShaderMode);
 
 	if(!sp->geometryShader)
 	{
@@ -237,7 +253,7 @@ Result shaderProgramConfigure(shaderProgram_s* sp, bool sendVshCode, bool sendGs
 		GPU_SetShaderOutmap((u32*)gshDvle->outmapData);
 
 		//GSH input attributes stuff
-		GPUCMD_AddWrite(GPUREG_GSH_INPUTBUFFER_CONFIG, 0x08000000|(sp->geoShaderInputStride-1));
+		GPUCMD_AddWrite(GPUREG_GSH_INPUTBUFFER_CONFIG, 0x08000000|(sp->geoShaderInputStride-1)|(subdivision?0x100:0));
 		GPUCMD_AddIncrementalWrites(GPUREG_GSH_ATTRIBUTES_PERMUTATION_LOW, sp->geoShaderInputPermutation, 2);
 
 		GPUCMD_AddWrite(GPUREG_SH_OUTATTR_MODE, gshDvle->outmapMode);