From e5727e7e2a5e1ae96c9cf9e72519111eb3e67243 Mon Sep 17 00:00:00 2001
From: dariosamo <dariosamo@gmail.com>
Date: Sun, 21 Jun 2015 14:09:41 -0300
Subject: [PATCH] GL4 Translator: ADDs/MULs/SUBs changed to XZ instead of XY.
 Basic implementation of loops for FLOW_CONTROL.

---
 src/xenia/gpu/gl4/gl4_shader_translator.cc | 55 ++++++++++++++++++++--
 src/xenia/gpu/gl4/gl4_shader_translator.h  |  2 +
 2 files changed, 54 insertions(+), 3 deletions(-)

diff --git a/src/xenia/gpu/gl4/gl4_shader_translator.cc b/src/xenia/gpu/gl4/gl4_shader_translator.cc
index 91ee56766..1cbd15c9e 100644
--- a/src/xenia/gpu/gl4/gl4_shader_translator.cc
+++ b/src/xenia/gpu/gl4/gl4_shader_translator.cc
@@ -105,6 +105,17 @@ std::string GL4ShaderTranslator::TranslateVertexShader(
   for (uint32_t n = 0; n <= temp_regs; n++) {
     Append("  vec4 r%d = state.float_consts[%d];\n", n, n);
   }
+
+#if FLOW_CONTROL
+  // Add temporary integer registers for loops that we may use.
+  // Each loop uses an address, counter, and constant
+  // TODO: Implement only for the used loops in the shader
+  for (uint32_t n = 0; n < 32; n++) {
+    Append("  int i%d_cnt = 0;\n", n);
+    Append("  int i%d_addr = 0;\n", n);
+  }
+#endif
+
   Append("  vec4 t;\n");
   Append("  vec4 pv;\n");   // Previous Vector result.
   Append("  float ps;\n");  // Previous Scalar result (used for RETAIN_PREV).
@@ -197,8 +208,14 @@ void GL4ShaderTranslator::AppendSrcReg(const instr_alu_t& op, uint32_t num,
       Append("abs(");
     }
     Append("state.float_consts[");
+#if FLOW_CONTROL
+    // NOTE(dariosamo): Some games don't seem to take into account the relative a0
+    // offset even when they should due to const_slot being a different value.
+    if (op.const_0_rel_abs || op.const_1_rel_abs) {
+#else
     if ((const_slot == 0 && op.const_0_rel_abs) ||
         (const_slot == 1 && op.const_1_rel_abs)) {
+#endif
       if (op.relative_addr) {
         assert_true(num < 256);
         Append("a0 + %u", is_pixel_shader() ? num + 256 : num);
@@ -783,7 +800,7 @@ bool GL4ShaderTranslator::TranslateALU_ADDs(const instr_alu_t& alu) {
   AppendScalarOpSrcReg(alu, 3);
   Append(".x + ");
   AppendScalarOpSrcReg(alu, 3);
-  Append(".y");
+  Append(".z");
   EndAppendScalarOp(alu);
   return true;
 }
@@ -801,7 +818,7 @@ bool GL4ShaderTranslator::TranslateALU_MULs(const instr_alu_t& alu) {
   AppendScalarOpSrcReg(alu, 3);
   Append(".x * ");
   AppendScalarOpSrcReg(alu, 3);
-  Append(".y");
+  Append(".z");
   EndAppendScalarOp(alu);
   return true;
 }
@@ -1027,7 +1044,7 @@ bool GL4ShaderTranslator::TranslateALU_SUBs(const instr_alu_t& alu) {
   AppendScalarOpSrcReg(alu, 3);
   Append(".x - ");
   AppendScalarOpSrcReg(alu, 3);
-  Append(".y");
+  Append(".z");
   EndAppendScalarOp(alu);
   return true;
 }
@@ -1457,6 +1474,12 @@ bool GL4ShaderTranslator::TranslateBlocks(GL4Shader* shader) {
     } else if (cfa.opc == COND_JMP) {
       TranslateJmp(cfa.jmp_call);
     }
+#if FLOW_CONTROL
+    else if (cfa.opc == LOOP_START) {
+      TranslateLoopStart(cfa.loop);
+    }
+#endif  // FLOW_CONTROL
+
     if (cfb.opc == ALLOC) {
       // ?
     } else if (cfb.is_exec()) {
@@ -1471,6 +1494,12 @@ bool GL4ShaderTranslator::TranslateBlocks(GL4Shader* shader) {
     } else if (cfb.opc == COND_JMP) {
       TranslateJmp(cfb.jmp_call);
     }
+#if FLOW_CONTROL
+    else if (cfb.opc == LOOP_END) {
+      TranslateLoopEnd(cfb.loop);
+    }
+#endif
+
     if (cfa.opc == EXEC_END || cfb.opc == EXEC_END) {
       break;
     }
@@ -1654,6 +1683,26 @@ bool GL4ShaderTranslator::TranslateJmp(const ucode::instr_cf_jmp_call_t& cf) {
   return true;
 }
 
+bool GL4ShaderTranslator::TranslateLoopStart(const ucode::instr_cf_loop_t& cf) {
+  Append("  // %s", cf_instructions[cf.opc].name);
+  Append(" ADDR(0x%x) LOOP ID(%d)", cf.address, cf.loop_id);
+  if (cf.address_mode == ABSOLUTE_ADDR) {
+    Append(" ABSOLUTE_ADDR");
+  }
+  Append("\n");
+  Append(" i%d_addr = pc;\n", cf.loop_id);
+  Append(" i%d_cnt = 0;\n", cf.loop_id);
+  return true;
+}
+
+bool GL4ShaderTranslator::TranslateLoopEnd(const ucode::instr_cf_loop_t& cf) {
+  Append("  // %s", cf_instructions[cf.opc].name);
+  Append(" ADDR(0x%x) LOOP ID(%d)\n", cf.address, cf.loop_id);
+  Append(" i%d_cnt = i%d_cnt + 1;\n", cf.loop_id, cf.loop_id);
+  Append(" pc = (i%d_cnt < state.loop_consts[%d]) ? i%d_addr : pc;\n", cf.loop_id, cf.loop_id, cf.loop_id);
+  return true;
+}
+
 bool GL4ShaderTranslator::TranslateVertexFetch(const instr_fetch_vtx_t* vtx,
                                                int sync) {
   static const struct {
diff --git a/src/xenia/gpu/gl4/gl4_shader_translator.h b/src/xenia/gpu/gl4/gl4_shader_translator.h
index 17eedd148..5e0a8d490 100644
--- a/src/xenia/gpu/gl4/gl4_shader_translator.h
+++ b/src/xenia/gpu/gl4/gl4_shader_translator.h
@@ -156,6 +156,8 @@ class GL4ShaderTranslator {
   bool TranslateBlocks(GL4Shader* shader);
   bool TranslateExec(const ucode::instr_cf_exec_t& cf);
   bool TranslateJmp(const ucode::instr_cf_jmp_call_t& cf);
+  bool TranslateLoopStart(const ucode::instr_cf_loop_t& cf);
+  bool TranslateLoopEnd(const ucode::instr_cf_loop_t& cf);
   bool TranslateVertexFetch(const ucode::instr_fetch_vtx_t* vtx, int sync);
   bool TranslateTextureFetch(const ucode::instr_fetch_tex_t* tex, int sync);
 };