5 files changed, 116 insertions, 46 deletions

diff --git a/src/video_core/regs_rasterizer.h b/src/video_core/regs_rasterizer.h
index 2874fd127..4fef00d76 100644
--- a/src/video_core/regs_rasterizer.h
+++ b/src/video_core/regs_rasterizer.h
@@ -5,10 +5,10 @@
 #pragma once
 
 #include <array>
-
 #include "common/bit_field.h"
 #include "common/common_funcs.h"
 #include "common/common_types.h"
+#include "video_core/pica_types.h"
 
 namespace Pica {
 
@@ -31,7 +31,17 @@ struct RasterizerRegs {
 
     BitField<0, 24, u32> viewport_size_y;
 
-    INSERT_PADDING_WORDS(0x9);
+    INSERT_PADDING_WORDS(0x3);
+
+    BitField<0, 1, u32> clip_enable;
+    BitField<0, 24, u32> clip_coef[4]; // float24
+
+    Math::Vec4<float24> GetClipCoef() const {
+        return {float24::FromRaw(clip_coef[0]), float24::FromRaw(clip_coef[1]),
+                float24::FromRaw(clip_coef[2]), float24::FromRaw(clip_coef[3])};
+    }
+
+    INSERT_PADDING_WORDS(0x1);
 
     BitField<0, 24, u32> viewport_depth_range;      // float24
     BitField<0, 24, u32> viewport_depth_near_plane; // float24
diff --git a/src/video_core/renderer_opengl/gl_rasterizer.cpp b/src/video_core/renderer_opengl/gl_rasterizer.cpp
index aa95ef21d..7b0cd1b66 100644
--- a/src/video_core/renderer_opengl/gl_rasterizer.cpp
+++ b/src/video_core/renderer_opengl/gl_rasterizer.cpp
@@ -169,6 +169,8 @@ RasterizerOpenGL::RasterizerOpenGL() : shader_dirty(true) {
     glTexBuffer(GL_TEXTURE_BUFFER, GL_RGBA32F, proctex_diff_lut_buffer.handle);
 
     // Sync fixed function OpenGL state
+    SyncClipEnabled();
+    SyncClipCoef();
     SyncCullMode();
     SyncBlendEnabled();
     SyncBlendFuncs();
@@ -401,6 +403,18 @@ void RasterizerOpenGL::NotifyPicaRegisterChanged(u32 id) {
         SyncCullMode();
         break;
 
+    // Clipping plane
+    case PICA_REG_INDEX(rasterizer.clip_enable):
+        SyncClipEnabled();
+        break;
+
+    case PICA_REG_INDEX_WORKAROUND(rasterizer.clip_coef[0], 0x48):
+    case PICA_REG_INDEX_WORKAROUND(rasterizer.clip_coef[1], 0x49):
+    case PICA_REG_INDEX_WORKAROUND(rasterizer.clip_coef[2], 0x4a):
+    case PICA_REG_INDEX_WORKAROUND(rasterizer.clip_coef[3], 0x4b):
+        SyncClipCoef();
+        break;
+
     // Depth modifiers
     case PICA_REG_INDEX(rasterizer.viewport_depth_range):
         SyncDepthScale();
@@ -1280,6 +1294,20 @@ void RasterizerOpenGL::SetShader() {
     }
 }
 
+void RasterizerOpenGL::SyncClipEnabled() {
+    state.clip_distance[1] = Pica::g_state.regs.rasterizer.clip_enable != 0;
+}
+
+void RasterizerOpenGL::SyncClipCoef() {
+    const auto raw_clip_coef = Pica::g_state.regs.rasterizer.GetClipCoef();
+    const GLvec4 new_clip_coef = {raw_clip_coef.x.ToFloat32(), raw_clip_coef.y.ToFloat32(),
+                                  raw_clip_coef.z.ToFloat32(), raw_clip_coef.w.ToFloat32()};
+    if (new_clip_coef != uniform_block_data.data.clip_coef) {
+        uniform_block_data.data.clip_coef = new_clip_coef;
+        uniform_block_data.dirty = true;
+    }
+}
+
 void RasterizerOpenGL::SyncCullMode() {
     const auto& regs = Pica::g_state.regs;
 
diff --git a/src/video_core/renderer_opengl/gl_rasterizer.h b/src/video_core/renderer_opengl/gl_rasterizer.h
index 78e218efe..46c62961c 100644
--- a/src/video_core/renderer_opengl/gl_rasterizer.h
+++ b/src/video_core/renderer_opengl/gl_rasterizer.h
@@ -151,14 +151,21 @@ private:
         LightSrc light_src[8];
         alignas(16) GLvec4 const_color[6]; // A vec4 color for each of the six tev stages
         alignas(16) GLvec4 tev_combiner_buffer_color;
+        alignas(16) GLvec4 clip_coef;
     };
 
     static_assert(
-        sizeof(UniformData) == 0x460,
+        sizeof(UniformData) == 0x470,
         "The size of the UniformData structure has changed, update the structure in the shader");
     static_assert(sizeof(UniformData) < 16384,
                   "UniformData structure must be less than 16kb as per the OpenGL spec");
 
+    /// Syncs the clip enabled status to match the PICA register
+    void SyncClipEnabled();
+
+    /// Syncs the clip coefficients to match the PICA register
+    void SyncClipCoef();
+
     /// Sets the OpenGL shader in accordance with the current PICA register state
     void SetShader();
 
diff --git a/src/video_core/renderer_opengl/gl_shader_gen.cpp b/src/video_core/renderer_opengl/gl_shader_gen.cpp
index c536e61e1..9fe183944 100644
--- a/src/video_core/renderer_opengl/gl_shader_gen.cpp
+++ b/src/video_core/renderer_opengl/gl_shader_gen.cpp
@@ -25,6 +25,42 @@ using TevStageConfig = TexturingRegs::TevStageConfig;
 
 namespace GLShader {
 
+static const std::string UniformBlockDef = R"(
+#define NUM_TEV_STAGES 6
+#define NUM_LIGHTS 8
+
+struct LightSrc {
+    vec3 specular_0;
+    vec3 specular_1;
+    vec3 diffuse;
+    vec3 ambient;
+    vec3 position;
+    vec3 spot_direction;
+    float dist_atten_bias;
+    float dist_atten_scale;
+};
+
+layout (std140) uniform shader_data {
+    vec2 framebuffer_scale;
+    int alphatest_ref;
+    float depth_scale;
+    float depth_offset;
+    int scissor_x1;
+    int scissor_y1;
+    int scissor_x2;
+    int scissor_y2;
+    vec3 fog_color;
+    vec2 proctex_noise_f;
+    vec2 proctex_noise_a;
+    vec2 proctex_noise_p;
+    vec3 lighting_global_ambient;
+    LightSrc light_src[NUM_LIGHTS];
+    vec4 const_color[NUM_TEV_STAGES];
+    vec4 tev_combiner_buffer_color;
+    vec4 clip_coef;
+};
+)";
+
 PicaShaderConfig PicaShaderConfig::BuildFromRegs(const Pica::Regs& regs) {
     PicaShaderConfig res;
 
@@ -1010,8 +1046,6 @@ std::string GenerateFragmentShader(const PicaShaderConfig& config) {
 
     std::string out = R"(
 #version 330 core
-#define NUM_TEV_STAGES 6
-#define NUM_LIGHTS 8
 
 in vec4 primary_color;
 in vec2 texcoord[3];
@@ -1023,36 +1057,6 @@ in vec4 gl_FragCoord;
 
 out vec4 color;
 
-struct LightSrc {
-    vec3 specular_0;
-    vec3 specular_1;
-    vec3 diffuse;
-    vec3 ambient;
-    vec3 position;
-    vec3 spot_direction;
-    float dist_atten_bias;
-    float dist_atten_scale;
-};
-
-layout (std140) uniform shader_data {
-    vec2 framebuffer_scale;
-    int alphatest_ref;
-    float depth_scale;
-    float depth_offset;
-    int scissor_x1;
-    int scissor_y1;
-    int scissor_x2;
-    int scissor_y2;
-    vec3 fog_color;
-    vec2 proctex_noise_f;
-    vec2 proctex_noise_a;
-    vec2 proctex_noise_p;
-    vec3 lighting_global_ambient;
-    LightSrc light_src[NUM_LIGHTS];
-    vec4 const_color[NUM_TEV_STAGES];
-    vec4 tev_combiner_buffer_color;
-};
-
 uniform sampler2D tex[3];
 uniform samplerBuffer lighting_lut;
 uniform samplerBuffer fog_lut;
@@ -1061,7 +1065,11 @@ uniform samplerBuffer proctex_color_map;
 uniform samplerBuffer proctex_alpha_map;
 uniform samplerBuffer proctex_lut;
 uniform samplerBuffer proctex_diff_lut;
+)";
+
+    out += UniformBlockDef;
 
+    out += R"(
 // Rotate the vector v by the quaternion q
 vec3 quaternion_rotate(vec4 q, vec3 v) {
     return v + 2.0 * cross(q.xyz, cross(q.xyz, v) + q.w * v);
@@ -1197,6 +1205,12 @@ out float texcoord0_w;
 out vec4 normquat;
 out vec3 view;
 
+)";
+
+    out += UniformBlockDef;
+
+    out += R"(
+
 void main() {
     primary_color = vert_color;
     texcoord[0] = vert_texcoord0;
@@ -1207,7 +1221,7 @@ void main() {
     view = vert_view;
     gl_Position = vert_position;
     gl_ClipDistance[0] = -vert_position.z; // fixed PICA clipping plane z <= 0
-    // TODO (wwylele): calculate gl_ClipDistance[1] from user-defined clipping plane
+    gl_ClipDistance[1] = dot(clip_coef, vert_position);
 }
 )";
 
diff --git a/src/video_core/swrasterizer/clipper.cpp b/src/video_core/swrasterizer/clipper.cpp
index cdbc71502..a52129eb7 100644
--- a/src/video_core/swrasterizer/clipper.cpp
+++ b/src/video_core/swrasterizer/clipper.cpp
@@ -31,7 +31,7 @@ public:
         : coeffs(coeffs), bias(bias) {}
 
     bool IsInside(const Vertex& vertex) const {
-        return Math::Dot(vertex.pos + bias, coeffs) <= float24::FromFloat32(0);
+        return Math::Dot(vertex.pos + bias, coeffs) >= float24::FromFloat32(0);
     }
 
     bool IsOutSide(const Vertex& vertex) const {
@@ -116,19 +116,18 @@ void ProcessTriangle(const OutputVertex& v0, const OutputVertex& v1, const Outpu
     static const float24 f0 = float24::FromFloat32(0.0);
     static const float24 f1 = float24::FromFloat32(1.0);
     static const std::array<ClippingEdge, 7> clipping_edges = {{
-        {Math::MakeVec(f1, f0, f0, -f1)},                                           // x = +w
-        {Math::MakeVec(-f1, f0, f0, -f1)},                                          // x = -w
-        {Math::MakeVec(f0, f1, f0, -f1)},                                           // y = +w
-        {Math::MakeVec(f0, -f1, f0, -f1)},                                          // y = -w
-        {Math::MakeVec(f0, f0, f1, f0)},                                            // z =  0
-        {Math::MakeVec(f0, f0, -f1, -f1)},                                          // z = -w
-        {Math::MakeVec(f0, f0, f0, -f1), Math::Vec4<float24>(f0, f0, f0, EPSILON)}, // w = EPSILON
+        {Math::MakeVec(-f1, f0, f0, f1)},                                          // x = +w
+        {Math::MakeVec(f1, f0, f0, f1)},                                           // x = -w
+        {Math::MakeVec(f0, -f1, f0, f1)},                                          // y = +w
+        {Math::MakeVec(f0, f1, f0, f1)},                                           // y = -w
+        {Math::MakeVec(f0, f0, -f1, f0)},                                          // z =  0
+        {Math::MakeVec(f0, f0, f1, f1)},                                           // z = -w
+        {Math::MakeVec(f0, f0, f0, f1), Math::Vec4<float24>(f0, f0, f0, EPSILON)}, // w = EPSILON
     }};
 
     // Simple implementation of the Sutherland-Hodgman clipping algorithm.
     // TODO: Make this less inefficient (currently lots of useless buffering overhead happens here)
-    for (auto edge : clipping_edges) {
-
+    auto Clip = [&](const ClippingEdge& edge) {
         std::swap(input_list, output_list);
         output_list->clear();
 
@@ -147,12 +146,24 @@ void ProcessTriangle(const OutputVertex& v0, const OutputVertex& v1, const Outpu
             }
             reference_vertex = &vertex;
         }
+    };
+
+    for (auto edge : clipping_edges) {
+        Clip(edge);
 
         // Need to have at least a full triangle to continue...
         if (output_list->size() < 3)
             return;
     }
 
+    if (g_state.regs.rasterizer.clip_enable) {
+        ClippingEdge custom_edge{g_state.regs.rasterizer.GetClipCoef()};
+        Clip(custom_edge);
+
+        if (output_list->size() < 3)
+            return;
+    }
+
     InitScreenCoordinates((*output_list)[0]);
     InitScreenCoordinates((*output_list)[1]);