From f53dbafdae6b6ca8ab718d2299437df469441389 Mon Sep 17 00:00:00 2001
From: tfarley <tfarleygithub@gmail.com>
Date: Sun, 3 Jan 2016 15:46:54 -0800
Subject: [PATCH] hwrasterizer: Use depth offset

---
 src/video_core/renderer_opengl/gl_rasterizer.cpp | 16 ++++++++++++++++
 src/video_core/renderer_opengl/gl_rasterizer.h   |  6 +++++-
 src/video_core/renderer_opengl/gl_shader_gen.cpp |  4 +++-
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/src/video_core/renderer_opengl/gl_rasterizer.cpp b/src/video_core/renderer_opengl/gl_rasterizer.cpp
index 092351dcee..291ef737d7 100644
--- a/src/video_core/renderer_opengl/gl_rasterizer.cpp
+++ b/src/video_core/renderer_opengl/gl_rasterizer.cpp
@@ -126,6 +126,7 @@ void RasterizerOpenGL::InitObjects() {
 
 void RasterizerOpenGL::Reset() {
     SyncCullMode();
+    SyncDepthModifiers();
     SyncBlendEnabled();
     SyncBlendFuncs();
     SyncBlendColor();
@@ -194,6 +195,12 @@ void RasterizerOpenGL::NotifyPicaRegisterChanged(u32 id) {
         SyncCullMode();
         break;
 
+    // Depth modifiers
+    case PICA_REG_INDEX(viewport_depth_range):
+    case PICA_REG_INDEX(viewport_depth_far_plane):
+        SyncDepthModifiers();
+        break;
+
     // Blending
     case PICA_REG_INDEX(output_merger.alphablend_enable):
         SyncBlendEnabled();
@@ -602,6 +609,15 @@ void RasterizerOpenGL::SyncCullMode() {
     }
 }
 
+void RasterizerOpenGL::SyncDepthModifiers() {
+    float depth_scale = -Pica::float24::FromRawFloat24(Pica::g_state.regs.viewport_depth_range).ToFloat32();
+    float depth_offset = Pica::float24::FromRawFloat24(Pica::g_state.regs.viewport_depth_far_plane).ToFloat32() / 2.0f;
+
+    // TODO: Implement scale modifier
+    uniform_block_data.data.depth_offset = depth_offset;
+    uniform_block_data.dirty = true;
+}
+
 void RasterizerOpenGL::SyncBlendEnabled() {
     state.blend.enabled = (Pica::g_state.regs.output_merger.alphablend_enable == 1);
 }
diff --git a/src/video_core/renderer_opengl/gl_rasterizer.h b/src/video_core/renderer_opengl/gl_rasterizer.h
index 92b1f812e8..c8a2d8f163 100644
--- a/src/video_core/renderer_opengl/gl_rasterizer.h
+++ b/src/video_core/renderer_opengl/gl_rasterizer.h
@@ -197,7 +197,8 @@ private:
         std::array<GLfloat, 4> const_color[6];
         std::array<GLfloat, 4> tev_combiner_buffer_color;
         GLint alphatest_ref;
-        INSERT_PADDING_BYTES(12);
+        GLfloat depth_offset;
+        INSERT_PADDING_BYTES(8);
     };
 
     static_assert(sizeof(UniformData) == 0x80, "The size of the UniformData structure has changed, update the structure in the shader");
@@ -218,6 +219,9 @@ private:
     /// Syncs the cull mode to match the PICA register
     void SyncCullMode();
 
+    /// Syncs the depth scale and offset to match the PICA registers
+    void SyncDepthModifiers();
+
     /// Syncs the blend enabled status to match the PICA register
     void SyncBlendEnabled();
 
diff --git a/src/video_core/renderer_opengl/gl_shader_gen.cpp b/src/video_core/renderer_opengl/gl_shader_gen.cpp
index 38de5d469c..22022f7f4f 100644
--- a/src/video_core/renderer_opengl/gl_shader_gen.cpp
+++ b/src/video_core/renderer_opengl/gl_shader_gen.cpp
@@ -334,6 +334,7 @@ layout (std140) uniform shader_data {
     vec4 const_color[NUM_TEV_STAGES];
     vec4 tev_combiner_buffer_color;
     int alphatest_ref;
+    float depth_offset;
 };
 
 uniform sampler2D tex[3];
@@ -360,7 +361,8 @@ void main() {
         out += ") discard;\n";
     }
 
-    out += "color = last_tex_env_out;\n}";
+    out += "color = last_tex_env_out;\n";
+    out += "gl_FragDepth = gl_FragCoord.z + depth_offset;\n}";
 
     return out;
 }